Effect of rare earth and alloying elements on the thermal conductivity of austenitic medium manganese steel

The influence of different contents of Cr, Mo, and rare earth element(RE) additives on the thermal conductivity of austenitic medium manganese steel was studied and discussed. The results show that the addition of Cr in medium manganese steel can improved the ordering of C–Mn atomic clusters, so as to improve the steel's thermal conductivity. However, Cr will lead to precipitation of a great deal of carbides in medium manganese steel when its content is greater than 4wt%. These carbides would aggregate around the grain boundary, and as a result, the thermal conductivity is decreased. By the addition of Mo whose content is about 2wt%, spherical carbides will be formed, thus improving the thermal conductivity of the medium manganese steel. The interaction between rare earth elements and alloying elements will raise both the thermal conductivity and the wear-resisting property of medium manganese steel.

Heavy Metal Control in Domestic Rubbish by Source Screening and Suitability of Nutrient Elements as Turfgrass Medium

This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgrass medium. Heavy metals in domestic rubbish were controlled by source screening before composting. The study consisted of a control with garden soil. The contents of main mineral elements and heavy metals in rubbish compost and control were determined by the method of ICP-AES. The results showed that heavy metal concentrations in rubbish were lower than those in garden soil, and little difference occurred between rubbish and garden soil in main mineral element concentrations. Based on this, it was concluded that rubbish compost was favorable for using as turfgrass medium and heavy metal control in rubbish by source screening was effective.

Membrane finite element method for simulating fluid flow in porous medium

A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous finite element theory, and can be easily coupled with the normal Galerkin finite element method. Based on the saturated seepage equation, the element coefficient matrix of the membrane element method is derived, and a geometric transform relation for the membrane element between a global coordinate system and a local coordinate system is obtained. A method for the determination of the fluid flux conductivity of the membrane element is presented. This method provides a basis for determining discontinuous parameters in discontinuous finite element theory. An anti-seepage problem regarding the foundation of a building is analyzed by coupling the membrane finite element method with the normal Galerkin finite element method. The analysis results demonstrate the utility and superiority of the membrane finite element method in fluid flow analysis of a porous medium.

MEDIUM-RANGE OSCILLATION OF METEOROLOGICAL ELEMENTS AT GREAT WALL STATION,ANTARCTICA

A method of multi-spectral analysis is used to study the spectral characteristics of surface and upper-level meteorological elements over the Great Wall Station (62°12'S, 58°57'W), Antarctica and their phasecorrelation, propagation of mean oscillation at 500hPa level in the Southern Hemisphere and their corresponding synoptic sense. the results are summed up as follows: 1. Over the sub-Antatctic zone, as in the Northern Hemisphere there generally exist quasi-weekly oscillation and quasi-biweekly oscillation. In different seasons the oscillations of meteorological elements are different: in winter season quasi-biweekly oscillation is dominant, while in summer season quasi-weekly oscillation is dominant. 2. From the Earth's surface to the lower stratosphere there is a distinct quasi-weekly oscillation at each isobaric surface, but the most intense oscillation appears at 200-300hPa, and the oscillations of height and temperature are propagated downward. 3. Both in winter and summer seasons the quasi-biweekly oscillation are propagated from west to east, and the mean velocity of its propagation is about 7-17 longtitude / day. 4. The quasi-biweekly oscillation and the quasi-weekly oscillation over the sub - Antarctic zone are closely related to the activity and intensity variation of polar vortex at 500hPa, while at 1000hPa they reflect an interaction between the circumpolar depression and the sub-tropical high. The quasi-biweekly oscillation may be a reflection of inherent oscillation of the polar vortex, where as the quasi-weekly oscillation is a result of forced oscillation by external disturbance.A large number of calculations and analysis made reveals the features of medium-range oscillation over the sub-Antarctic zone. The results are of significance for understanding the behaviour of synoptic dynamics and making the weather forecast.This work is supported by National Committee for Antarctic Research.

An explicit finite element method for dynamic analysis in three-medium coupling system and its application

In this paper, an explicit finite element method to analyze the dynamic responses of three-medium coupled systems with any terrain is developed on the basis of the numerical simulation of the continuous conditions on the bounda-ries among fluid saturated porous medium, elastic single-phase medium and ideal fluid medium. This method is a very effective one with the characteristic of high calculating speed and small memory needed because the formulae for this explicit finite element method have the characteristic of decoupling, and which does not need to solve sys-tem of linear equations. The method is applied to analyze the dynamic response of a reservoir with considering the dynamic interactions among water, dam, sediment and basement rock. The vertical displacement at the top point of the dam is calculated and some conclusions are given.

Numerical simulation of influences of the earth medium's lateral heterogeneity on co- and post-seismic deformation

Many studies revealed that the Earth medium＇s lateral heterogeneity can cause considerable effects on the co- and post-seismic deformation field. In this study, the threedimensional finite element numerical method are adopted to quantify the effects of lateral heterogeneity caused by material parameters and fault dip angle on the co- and postseismic deformation in the near- and far-field. Our results show that： 1） the medium＇s lateral heterogeneity does affect the co-seismic deformation, with the effects increasing with the medium＇s lateral heterogeneity caused by material parameters; 2） the Lame parameters play a more dominant role than density in the effects caused by lateral heterogeneity; 3） when a fault＇s dip angle is smaller than 90, the effects of the medium＇s lateral heterogeneity on the hanging wall are greater than on the footwall; 4） the impact of lateral heterogeneity caused by the viscosity coefficient on the post-seismic deformation can affect a large area, including the near- and far-field.

An RKDG finite element method for the one-dimensional inviscid compressible gas dynamics equations in a Lagrangian coordinate

In this paper,Runge-Kutta Discontinuous Galerkin（RKDG） finite element method is presented to solve the onedimensional inviscid compressible gas dynamic equations in a Lagrangian coordinate.The equations are discretized by the DG method in space and the temporal discretization is accomplished by the total variation diminishing Runge-Kutta method.A limiter based on the characteristic field decomposition is applied to maintain stability and non-oscillatory property of the RKDG method.For multi-medium fluid simulation,the two cells adjacent to the interface are treated differently from other cells.At first,a linear Riemann solver is applied to calculate the numerical ？ux at the interface.Numerical examples show that there is some oscillation in the vicinity of the interface.Then a nonlinear Riemann solver based on the characteristic formulation of the equation and the discontinuity relations is adopted to calculate the numerical ？ux at the interface,which suppresses the oscillation successfully.Several single-medium and multi-medium fluid examples are given to demonstrate the reliability and efficiency of the algorithm.

农田土壤有效态中量微量元素的时空变化特征研究

基于2019年的耕地地力调查监测点,分析农田土壤有效态中量微量元素含量及区域分布特征,结合分级标准和缺素临界值,揭示当前土壤中量微量元素丰缺状况;并对1983年、2004年的土壤的中微量元素有效态含量进行分析。结果表明:现阶段上海市奉贤地区农田土壤有效态中量微量元素养分中Av-S含量为20—30 mg∕kg,Av-Si>300 mg∕kg,Av-Cu 4—6 mg∕kg,Av-Zn 2—3 mg∕kg,Av-Fe 100—150 mg∕kg,Av-Mn 30—40 mg∕kg,Av-B 0.75—1 mg∕kg,Av-Mo 0.1—0.15 mg∕kg,平均含量依次为20.04 mg∕kg、390.92 mg∕kg、4.31 mg∕kg、2.42 mg∕kg、131.08 mg∕kg、34.74 mg∕kg、0.95 mg∕kg和0.13 mg∕kg,分别处于土壤养分分级标准(5级)的第3、1、3、2、2、2、2、3级。这8种中微量元素变异系数均为中等变异强度,以Av-Fe(90.39%)最大。在1983年、2004年、2019年三个时间上,除Av-Mo含量整体变化较为平稳,缺素现象在不断加剧(目前缺素面积达73.68%)外,其余中微量元素在整体上有不同程度的增减,无缺素现象或缺素面积在减少。中量元素Av-S和Av-Si含量变化为一降一升,两者均在果园中高于其他土地利用方式;微量元素Av-Cu、Av-Fe、Av-Mn总体含量比较丰富,无低于临界值田块,在空间分布上为条状或斑状分布,呈自西往东逐渐减少格局,其菜地中的含量要低于粮田和果园;Av-Zn和Av-B含量在年际间不断提高,菜地中的含量普遍较高,区域分布上呈现相反趋势,Av-Zn为中部高东西部低,而Av-B为东西部高于中部。同时土壤多个微量元素间存在较高的相关性,Av-Cu、Av-Zn、Av-Fe、Av-Mn间表现出正相关性,它们也受土壤SOM和pH影响较大,其中Av-Cu受SOM、Av-Mn受pH作用最明显。研究结果可为本区不同土地利用方式及区域分布的土壤养分管理和中微肥合理搭配提供依据。

咖啡土壤的中量和微量元素含量与咖啡豆杯测品质的相关性分析

[目的]探索土壤中的中量和微量元素含量及其与咖啡豆杯测品质之间的相关性。[方法]通过对普洱市5个县(区)10个咖啡种植园土壤中的中量和微量元素有效含量进行检测分析。[结果]土壤pH为3.77~5.28,为酸性,土壤交换性钙、交换性镁、有效硼、有效钼含量为低水平,土壤有效锌、有效铜含量处于中水平,土壤有效铁、有效锰含量处于高水平;有效硫含量样点间差异较大,6个处于较低水平,4个含量较高;有效铜和有效锰之间相关性达到显著水平,交换性钙和交换性镁之间呈极显著相关;大部分杯测品质指标之间差异呈显著或极显著相关;土壤交换性钙、交换性镁、土壤有效硫、铁、锰、硼、硼、钼、铜与咖啡豆杯测品质的相关性均不显著。

Modeling and Simulation of High Frequency Electromagnetics Wave Propagation on Vivaldi Antenna Using Finite Element Method

The simulation of the electromagnetic wave propagation plays an important role in predicting the performance of wireless transmission and communication systems. This research paper performs a numerical simulation using the finite element method (FEM) to study electromagnetic propagation through both conductive and dielectric media. The simulations are made using the COMSOL Multiphysics software which notably implements the finite element method. The microwave is produced by a Vivaldi antenna at the respective frequencies of 2.6 and 5 GHz and the propagation equation is formulated from Maxwell’s equations. The results obtained show that in the air, strong electric fields are observed in the slot and the micro-strip line for the two frequencies, they are even greater when the wave propagates in the glass and very weak for the copper. The 3D evolutions of the wave in air and glass present comparable values at equal frequencies, the curves being more regular in air (dielectric). The radiation patterns produced for air and glass are directional, with a large main lobe, which is narrower at 5 GHz. For copper, the wave propagation is quite uniform in space, and the radiation patterns show two main lobes with a much larger size at 2.6 GHz than at 5 GHz. The propagation medium would therefore influence the range of values of the gain of the antenna.

不同配方基肥对温郁金产量及其营养元素含量的影响

本试验研究了基肥氮磷钾不同比例配施对温郁金产量与品质的影响,为提高温郁金产量及品质提供科学依据。本研究采用大田试验,设置4个不同的施肥配方,各处理基肥用量均为750 kg·hm^(-2)。结果表明,在氮磷钾总用量相等的前提下,基施配方肥2的温郁金产量最高,与常规施肥比较,温郁金地下部分根茎、块根分别增产11.3%、17.9%。配方肥1和3相较常规施肥也提高了温郁金的产量,但统计上无显著差异。与常规施肥相比,配方肥处理提高了温郁金中氮和磷含量。同时,基施配方肥还可以提高根茎、块根中Ca、Mg及微量元素Zn、B等含量。综上,基肥施用配方肥2既能提高温郁金产量,又能提高根茎、块根中的大量元素及中微量元素含量,具有较好的推广应用价值。

我国主要粮食产区土壤有效态钙镁硫的变化特征及其对作物产量的影响

中量元素钙、镁、硫对农业生产的作用日益突出,研究土壤有效态钙镁硫的变化特征及其对作物产量的影响,可为全国和区域尺度耕地土壤中量元素管理和合理施肥提供理论依据。基于覆盖全国697个耕地质量监测点的监测数据,对比分析2016和2021年全国及六大粮食产区(东北区、华北区、西北区、西南区、长江流域和华南区)的土壤有效态钙镁硫含量的变化特征及其对主要粮食作物产量的影响。与2016年相比,2021年697个监测点的土壤交换性钙和交换性镁平均含量变化不显著,有效硫平均含量显著下降了27.3%,全国交换性钙、交换性镁和有效硫主要与土壤pH和有机质(OM)相关。六大粮食产区土壤有效态钙镁硫含量的年际变化特征有所不同。与2016年相比,2021年东北区交换性钙和镁含量分别显著增加了25.5%和52.4%,主要与pH相关;有效硫含量显著下降了47.8%,主要与速效钾相关。华北区交换性钙含量显著下降了11.8%,主要与pH相关。西北区交换性钙、镁和有效硫含量分别显著下降了64.0%、54.0%和30.4%,钙主要与总钾相关,镁主要与全磷相关,硫与土壤其他理化性质不存在显著相关。西南区有效硫含量显著下降了30.0%,主要与pH和OM相关。长江流域交换性镁和有效硫含量分别显著下降了52.0%和15.7%,主要与pH和OM相关。华南区3种有效态中量元素含量变化不显著,三者主要与pH和OM相关。在全国尺度下,水稻产量与土壤交换性钙和镁含量呈显著正相关,玉米产量与交换性镁和有效硫含量呈显著正相关,小麦产量则与3种中量元素不存在显著相关性;当pH≤7.0时,小麦产量与交换性钙和镁含量呈显著正相关,当pH>7.0时则不存在显著相关性;无论土壤呈酸性还是碱性,小麦产量均与有效硫含量不存在显著相关性。综上,2016—2021年的5年间,我国耕地土壤交换性钙、镁含量变化不显著,有效硫含量显著降低,这些中量元素主要与土壤pH和OM相关。六大粮食产区中量元素含量变化特征和影响因素及其对主要粮食作物产量的影响存在较大差异,针对性施用中量元素肥料有助于提升区域粮食产量。

Boundary element analysis for elastic and elastoplastic problems of 2D orthotropic media with stress concentration

Both the orthotropy and the stress concentration are common issues in modem structural engineering. This paper introduces the boundary element method （BEM） into the elastic and elastoplastic analyses for 2D orthotropic media with stress concentration. The discretized boundary element formulations are established, and the stress formulae as well as the fundamental solutions are derived in matrix notations. The numerical procedures are proposed to analyze both elastic and elastoplastic problems of 2D orthotropic me- dia with stress concentration. To obtain more precise stress values with fewer elements, the quadratic isoparametric element formulation is adopted in the boundary discretization and numerical procedures. Numerical examples show that there are significant stress concentrations and different elastoplastic behaviors in some orthotropic media, and some of the computational results are compared with other solutions. Good agreements are also observed, which demonstrates the efficiency and reliability of the present BEM in the stress concentration analysis for orthotropic media.

普洱市茶园土壤pH、有机质和中微量养分分析及肥力综合评价

【目的】采用土壤肥力综合评价指数法对普洱市茶园土壤pH、有机质和中微量元素含量进行综合评价,为普洱市茶园土壤养分管理和茶叶品质提升提供科学指导。【方法】采集普洱市4个典型茶叶种植区的40个茶园土壤样品,测定土壤pH、有机质及中微量元素(钙、镁、铁、锰、铜、锌)有效含量,采用隶属度函数模型计算土壤肥力综合指数,综合评价普洱市茶园土壤养分特征和肥力质量。【结果】普洱市茶园土壤总体呈酸性,pH为4.0~5.8,平均值为4.8。土壤有机质、有效钙、有效镁、有效铁、有效锰、有效铜和有效锌含量为4.9~41.6 g/kg、87.7~2351.9 mg/kg、56.9~272.2 mg/kg、40.3~107.3 mg/kg、2.8~64.8 mg/kg、0.3~2.9 mg/kg和0.5~5.2 mg/kg,平均值为23.4 g/kg、853.8 mg/kg、134.5 mg/kg、77.8 mg/kg、38.3 mg/kg、1.2 mg/kg和2.7 mg/kg,平均含量均达适宜水平,但不同茶园空间分布差异较大。其中,95.0%茶园表层土壤有机质含量、55.0%茶园土壤有效钙含量、62.5%茶园土壤有效镁含量达适宜及以上水平,95.0%以上茶园土壤的微量元素有效铁、有效锰、有效铜和有效锌含量适宜茶树生长。茶园土壤肥力综合指数为0.59~1.00,平均值为0.83,土壤营养状况总体较好。土壤肥力综合指数与有机质、有效镁、有效锰、有效铜和有效锌含量呈极显著正相关(P<0.01)。【结论】普洱市茶园土壤pH、有机质含量适宜高产优质茶树种植,针对土壤有效钙和有效镁等中量元素含量不足,铁、锰、铜、锌等微量元素含量过高及养分空间分布不均衡现状,需进行优化施肥和科学精准施肥,适当控制微量元素投入,加强茶园土壤测土配方工作,以维持普洱市茶园的高产优质生产。

Research of Inorganic Heat Transfer Element Starting Proprerty

This article studies the wall temperature distribution of inorganic heat transfer element in different working conditions by experiments, and analyzes the impact of inclination angle, heating power, different kinds of cooling medium and different inlet temperature of cooling medium on the starting property of inorganic heat transfer element.

金属网格-透明导电氧化物复合型透明电极的瑞利分析和仿真

以氧化铟锡(indium tin oxide,ITO)为代表的透明导电氧化物(transparent conducting oxide,TCO)在当前光电器件中的重要性日益增长.通过在TCO中引入金属网格构成复合电极,可以在保持良好透明性的前提下有效提升电学性能,同时降低对铟的需求量,并为可穿戴设备所需的柔性电极提供可能方案.对此类电极的电学性能分析,如复合电极方阻随金属网格结构参数的变化,可为电极设计与制备提供基本的出发点,但相关理论尚十分缺乏.本文针对典型的方孔方格型金属网格-TCO复合电极,分别展开基于瑞利模型和基于有限元仿真的电学性能分析.结果表明,孔型近似导致的金属通道显著畸变是复合电极的电学计算中瑞利模型在中高开口率下失效的主要原因.据此,我们采用格型修正,通过提升瑞利模型中的原胞外边界对称性来改善金属通道的畸变.与电极仿真的对比表明,修正后瑞利模型的适用范围明显扩大,其结果可与实验数据很好地拟合,为此类复合透明电极的电学数据分析与结构设计提供了简洁高效的理论工具.

中微量元素对水稻产量和品质的影响研究进展

中微量元素作为水稻生长发育所必需的营养元素,是多种酶系统的构成要素和激活剂,同时还参与光合作用、呼吸作用、激素合成及抗逆等一系列重要生理过程,对水稻生长及产量和品质的形成起着重要作用。因此,综述了对水稻具有显著作用的镁、锌、硒、铁元素的吸收、积累和代谢途径,以及它们对水稻产量和品质的影响,并深入分析了中微量元素在水稻生产中所面临的挑战,探讨了中微量元素在未来可持续发展农业中的必要性以及研究方向,旨在为通过合理施用中微量元素实现水稻高产和优质提供理论依据。

减化增施有机肥和新型肥料对辣椒农艺性状及产量的影响

为观测新型肥料与常规肥料不同配施方案在辣椒生长和产量上的作用,选用菌肥(地康宝)、有机硅钙镁肥和土壤调理剂(蓝海半岛)3种新型肥料,设计了9个肥料配施方案进行试验研究。结果表明,随着有机肥增施和复合肥减施,产量呈先升后降的趋势,在T2[机肥2 000 kg·(667 m^(2))^(-1)+复合肥40 kg·(667 m^(2))^(-1)]时最高,较对照总施肥量提高30.77%,增产25.25%,但肥料利用率(PFP)较对照下降4.25%;新型肥料处理相较于对照均增加了地下部分干物质含量,其中T6[有机肥1 500 kg·(667 m^(2))^(-1)+复合肥60 kg·(667 m^(2))^(-1)+有机硅钙镁肥60 kg·(667 m^(2))^(-1)]有明显增产效果,产量和偏生产力(PFP)分别比对照高43.81%和38.61%,较T2总施肥量减少20.59%,增产14.82%,PFP提高44.76%;T5处理地康宝菌肥能提高PFP,但与对照差异不显著;通过不同的配施方案研究还发现所选3种新型肥料的肥效不够稳定,还需要后续完善改进。

不同施肥组合对科尔沁沙地南缘沙地土壤健康指标的影响

为研究不同施肥组合对沙地土壤改良的效果,以辽宁省阜新市彰武县的沙地土壤为考察对象,开展了试验研究。试验以不施肥为对照(CK)处理,设置生物有机肥分别与含腐殖酸肥料(OH)、含聚谷氨酸肥料(OP)和中微量元素肥(OM)混施3个施肥处理,测定施肥后6、12、18个月的土壤中微生物数量和土壤理化性状的变化。结果表明:不同施肥处理的土壤中微生物数量均呈现细菌>放线菌>真菌的变化趋势,其中OH处理的细菌数量最多,3个取样时间的细菌数量平均值为1.510×10^(7)cfu/g,是CK处理的5.2倍;施肥处理的土壤中全磷、全钾和有机质含量均得到提高,OP处理的全钾含量平均值最高,质量分数为5.96 g/kg;施肥处理的土壤pH均呈下降趋势;施肥处理的地上部植物生物量提高。施用不同组合的肥料可以有效提高土壤微生物的数量,改善土壤理化性状,提高地上部植物生物量,是一种合理的沙地改良措施。

油茶林地中微量养分与果实经济性状的相关性

【目的】为油茶营养精准管理提供参考。【方法】以湖南省4个油茶栽培区油茶‘华金’林分为对象,测定林地土壤及油茶叶片中微量元素含量,并分析其与果实经济指标的关系。【结果】在不同产量水平下油茶林分土壤中Ca、Mg、Mn、B、Fe含量与叶片中Ca、Mg、Mn、Fe、Zn的含量及果实干出仁率、种仁含油率、种仁蛋白质、淀粉含量、茶油硬脂酸含量差异均达到显著水平(P<0.05)。回归分析结果显示土壤与叶片Ca含量是油茶产量的主控因子(F=9.210,7.649;P=0.006,0.011);土壤Mg含量和叶片Mn含量均与干出仁率呈显著正相关(F=6.584,4.566;P=0.018,0.044);种仁含油率与土壤Fe含量存在显著负相关,而与叶片Mg含量存在显著正相关(F=9.387,13.613;P=0.006,0.001)。土壤Mn含量分别与单果质量、棕榈酸含量、花生酸含量均存在显著正相关,与油酸含量存在一定的负相关(F=4.350,11.535,9.160,5.922;P=0.049,0.003,0.006,0.024)。相关性分析结果表明土壤B含量与叶片中Ca含量呈显著正相关(r=0.748);土壤Zn含量与叶片中Mn含量呈显著正相关(r=0.917)。【结论】土壤中B、Zn含量促进叶片对Ca、Mn元素的吸收,提高土壤与叶片中Ca含量则有利于产量的增加。叶片Mg含量有利于种仁含油率的提升,土壤中Fe含量过多可能会抑制油脂的积累。叶片Mn含量可促进干出仁率的增加,脂肪酸组成主要受土壤Mn含量影响。