Analysis of genotype differences of rice response to low Zn^(2+) activity and some morphological characteristics

Zinc deficiency is one of the most widespreadmicro-nutritional disorder for rice. To solve the problem, screening Zn-efficient cultivars isan available method and understanding geno-

Dynamics Response and Non⁃linear Characteristics Analysis of Complex Planar 2⁃DOF Mechanism with Revolute Clearances

There are clearances in mechanism because of manufacture and assembly error,which reduces operation life and working accuracy of mechanism and has a great impact on dynamical responses.At the moment,research in this area mainly focuses on single degree⁃of⁃freedom mechanism considering one clearance,while research of multi⁃DOF mechanism considering multi⁃clearance is less.With the purpose of studying the dynamical characteristics of complex multi⁃DOF mechanism with multi⁃clearances,a dynamic model was developed.The dynamic responses of 2⁃DOF mechanism with two clearances under different positions,values,and numbers of clearance were analyzed.The displacement,velocity,acceleration,collision force,and the axis trajectory at clearance were then given.In addition,there is a limited amount of literature on chaotic phenomena,which mainly focuses on the chaotic phenomena of end⁃effector of mechanism.But in this paper,the non⁃linear characteristics were analyzed by chaotic phenomenon of clearance joint,then chaotic phenomenon was identified by Poincarémappings and phase diagrams.Bifurcation diagrams were given.The results will offer a reliable technical support for the study of dynamical responses of planar mechanisms and the analysis of chaotic phenomena.

Seismic response reduction analysis of large chassis base-isolated structure under long-period ground motions

Long-period structures(e.g.Isolated structures)tend to produce pseudo-resonance with low frequency compo-nents of long-period ground motions,resulting in the increase in damage.Stiffness mutation occurs due to the set-back in the upper body of the large chassis structure.In the parts with stiffness mutation,the torsion effect caused by the tower is far greater than that of the chassis itself.In this study,a total of 273 ground motions are collected and then filtered into four types,including the near-field ordinary,near-field pulse,far-field ordinary,and far-field harmonic.An 8-degree(0.2 g)fortified large chassis base-isolated structure is established.Furthermore,ETABS program software is used to conduct nonlinear time history analysis on the isolation and seismic model under bi-directional earthquake ground motions.The comparison results show that the seismic isolation effect of the base-isolated structure under long-period ground motions is worse than that associated with ordinary ground motions when the seismic response reduction rate of the large base floor significantly decreases compared with that of the tower.When the inter-story displacement angle and the displacement of isolation layer of the chassis exceeds the limit of Code for Seismic Design of Buildings(GB 50011-2010),it is recommended to adopt composite seismic isolation technology or add limit devices.Under the condition of long-period ground motions,the base-isolated structure reduces the lateral-torsional coupling effect of the large chassis structure,while the torsion response of large chassis’top layer increases.Under long-period ground motions with the same acceleration peak,the response of the base-isolated structure increases much more than that of the seismic structure and the consideration of this impact is suggested to be added to the Code.

Circuit-Level Analysis on Opto-Electronic Characteristics of Ferroelectric Liquid Crystal

We propose an electronic model in Spice, instead of traditional mathematical analysis, for analyzing the performance of ferroelectric liquid crystal （FLC） under various working conditions. Using this equivalent circuit model,it is easy to simulate and analyze the behavior of an FLC layer in three different typical parameters,including temperature, input light wavelength, and the frequency of driving voltage. We conclude that the response velocity drops as the wavelength increases in the range of visible light, and for the parameter of temperature, the velocity reaches its lowest value when the temperature reaches a certain degree,meanwhile,the frequency of driving voltage exerts important effects on the response velocity only when the frequency is beyond a critical value. Excellent agreement is achieved between simulation and experimental results.

Research on coupled thermo-hydro-mechanical dynamic response characteristics of saturated porous deep-sea sediments under vibration of mining vehicle

The excessive deformation of deep-sea sediments caused by the vibration of the mining machine will adversely affect the efficiency and safety of mining.Combined with the deep-sea environment,the coupled thermo-hydro-mechanical problem for saturated porous deep-sea sediments subject to the vibration of the mining vehicle is investigated.Based on the Green-Lindsay(G-L)generalized thermoelastic theory and Darcy’s law,the model of thermo-hydro-mechanical dynamic responses for saturated porous deep-sea sediments under the vibration of the mining vehicle is established.We obtain the analytical solutions of non-dimensional vertical displacement,excess pore water pressure,vertical stress,temperature,and change in the volume fraction field with the normal mode analysis method,and depict them graphically.The normal mode analysis method uses the canonical coordinate transformation to solve the equation,which can quickly decouple the equation by ignoring the modal coupling effect on the basis of the canonical mode.The results indicate that the vibration frequency has obvious influence on the vertical displacement,excess pore water pressure,vertical stress,and change in volume fraction field.The loading amplitude has a great effect on the physical quantities in the foundation,and the changes of the physical quantities increase with the increase in loading amplitude.

Seismic Response Analysis of Silo-Stock-Foundation Interaction System

To analyze the response law of silo-stock-foundation interaction system under seismic load, a dynamic equation of this interaction system was established. Furthermore, the dynamic characteristics of the silo-stock-foundation interaction system under different storage conditions were studied through numerical analysis. The displacement at the silo top was much greater than that at the silo bottom, while the vibration trend of the upper and lower silos on the same bus bar was similar. The acceleration response, dis-placement and stress response of the structure increased with the increase of the input seismic wave. Furthermore, the direction time responses of several typical silo parts were consistent. With increase in storage material, the acceleration peak of the silo and bulk material increased and then decreased. This indicates that the relative motion of the storage material and silo had a damping effect on the silo system. The maximum circumferential strain and equivalent stress of silos with different storage capacities were recorded at the variable section of silos (the top of funnel). The effective stress beneath foundations near silos was obviously higher than that far away from silos. These results can provide a reliable theoretical basis and reference values for mitigating silo structural failures under seismic load.

Comparison between Different Shapes of Structure by Response Spectrum Method of Dynamic Analysis

Several procedures for non-linear static and dynamic analysis of structures have been developed in recent years. In this paper, the response spectrum analysis is performed on two different shapes i.e. regular and irregular shape of structure by using STAAD PRO. And the comparison results are studied and compared accounting for the earthquake characteristics and the structure dynamic characteristics. As the results show that the earthquake response peak values and the main response frequencies are very close and comparable. It can be referred to by the engineering applications.

Effect of biometric characteristics on biomechanical properties of the cornea in cataract patient

AIM： To determine the impact of biometric characteristics on the biomechanical properties of the human cornea using the ocular response analyzer （ORA） and standard comprehensive ophthalmic examinations before and after standard phacoemulsificaUon. METHODS： This study comprised 54 eyes with cataract with significant lens opacification in stages I or II that underwent phacoemulsification （2.8 mm incision）. Corneal hysteresis （CH）, corneal resistance factor （CRF）, Goldmann-correlated intraocular pressure （IOPg）, and corneal-compensated intraocular pressure （IOPcc） were measured by ORA preoperatively and at lmo postoperatively. Biometric characteristics were derived from corneal topography [TMS-5, anterior equivalent （EQTMS） and cylindric （CYLTMS） power], corneal tomography [Casia, anterior and posterior equivalent （EQaCASC, EQpCASIA） and cylindric （CYLaCASIA, CYLpCASIA） power], keratometry [IOLMaster, anterior equivalent （EQIOL） and cylindric （CYL,oL） power] and autorefractor [anterior equivalent （EQAR）]. Results from ORA were analyzed and correlated with those from all other examinations taken at the same time point. RESULTS： Preoperatively, CH correlated with EQpCASIA and CYLpCASIA only （P=0.001, P=0.002）. Postoperatively, IOPg and IOPcc correlated with all equivalent powers （EQTMS, EQIOL, EQAR, EQaCASIA, and EQpCASIA）（P=0.001, P=0.007, P=0.001, P= 0.015, P=0.03 for IOPg and P〈0.001, ,0=0.003, P〈0.001, P= 0.009, P=0.014 for IOPcc）. CH correlated postoperatively with EQaCASIA and EQpCASIA only （P=0.021, P=0.022）. CONCLUSION： Biometric characteristics may significantly affect biomechanical properties of the cornea in terms of CH, IOPcc and IOPg before, but even more after cataract surgery.

Seismic Analysis for Rigid-Framed Prestressed Reinforced Concrete Bridge in Tianjin Light Railway

The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the soft soil foundation. After the dynamic characteristics are calculated in terms of natural frequencies and modes, the seismic analysis is carried out using the modal response spectrum method and the time-history method, respectively. Based on the calculated results, the reasonable design values are finally suggested as the basis of the seismic design of the bridge, and meanwhile the problems encountered were also analyzed. Finally, some conclusions are drawn as: 1) Despite the superiority of rigid-framed prestressed concrete bridge, the upper and lower ends of the piers of the bridge are proved to be the crucial parts of the bridge, which are easily destroyed under designed earthquake excitations and should be carefully analyzed and designed; 2) The soft soil foundation can possibly result in rather weakening of the lateral rigidity of the rigid-framed bridge, and should be paid considerable attention; 3) The modal response spectrum method, combined with time-history method, is suggested for the seismic analysis in engineering design of the rigid-framed prestressed concrete bridge.

氢气循环泵的转子动力学特性分析

基于ANSYS构建了用于燃料电池汽车氢气供应系统的氢气循环泵(罗茨泵)转子系统的模型,通过对转子系统的模态分析,得到了独立转子系统和双转子系统的前六阶固有振型和固有频率。在模态分析的基础上分析了转子系统的谐响应特性,获得了齿轮、叶轮边缘两个部位的谐响应特性曲线。结果表明:轴端、转子叶轮等结构振动变形量较大,在接近前三阶固有频率(960Hz左右)时转子系统振动响应幅值最大,双转子耦合系统相对于单独转子系统会出现更加复杂的振型,转子叶轮对不平衡量的响应更显著。研究将为氢气循环泵转子系统的设计制造和振动特性预估提供积极的参考作用,并为氢气循环泵动力学特性的研究奠定基础。

高墩大跨矮塔斜拉桥成桥动力特性及抗震分析

现代桥梁往高墩大跨径方向发展,对结构的动力特性和抗震能力提出了越来越高的要求。矮塔斜拉桥在这方面的研究还较少,因此本文以某待建高墩大跨矮塔斜拉桥为例,应用反应谱法和时程分析法对其进行研究,供其他同类型项目参考。

基于耐震时程法的高拱坝地震易损性分析

基于耐震时程分析方法(ETA),建立了三维坝体-库水-地基动力相互作用模型,进行高拱坝抗震性能评价。以基于目标反应谱合成的10条耐震加速度时程曲线为地震输入,选取坝体损伤体积比、坝顶坝踵顺河向相对位移和拱冠梁横缝开度作为结构性能指标,通过对结构不同性能水准的定义,建立了极限状态与结构性能指标之间的关系,以此为基础绘制易损性曲线。结果表明:随着耐震时程输入时间的增加,拱坝的各项响应值随之增大,不同响应指标对地震强度的敏感性不同,且ETA法与增量动力分析法(IDA)得到的响应结果基本一致,在同一性能水平下采用不同评价指标时对应的超越概率也不相同。因此,在进行结构的抗震性能评价时应综合考虑不同结构响应指标,选取不同性能下超越概率最大的结构响应指标进行分析。

国产低屈服点芯材屈曲约束支撑的滞回性能及减震效果研究

为了研究芯材为LY160软钢的屈曲约束支撑滞回性能以及减震效果,针对LY160钢材和BRB构件进行了从材性、构件性能、到结构地震响应的系统试验和分析工作。首先完成了LY160钢材的材性试验,得到LY160钢材试件的平均屈服强度为170MPa,断裂伸长率为48.2%;随后进行了屈曲约束支撑的低周往复加载试验,采用LY160的屈曲约束支撑破坏位移为1/45L,延性系数达到17,最后开展了6层钢筋混凝土框架结构的弹塑性地震响应分析,发现使用LY160芯材的LBRB结构相较于使用Q235芯材的普通NBRB结构,不仅结构动力响应的减震效果提升了25%,同时还可有效地改善结构在强震下的塑性损伤,采用低屈服点软钢为芯板的屈曲约束支撑可以有效提升结构的抗震安全性。

风电叶片摆锤式疲劳加载特性分析及研究

为探究疲劳加载过程中摆锤式激振器相关参数对叶片振动特性的影响,揭示加载过程中激振器电流的变化规律,基于拉格朗日方程建立叶片摆锤式疲劳加载系统动力学模型,分析摆锤式激振器的动力参数以及与叶片的相互作用,并对叶片进行疲劳加载。结果表明,激振器中旋转质量会改变叶片疲劳加载系统的固有频率,采用实测加载数据中旋转质量与叶片振动之间的实际相位差,修正理论模型,理论电流峰值相对于实际电流误差为8.5%。

汽车尾气温差发电系统瞬态回收性能分析

为了预测温差发电(thermoelectric generator, TEG)系统的动态特性,基于COMSOL Multiphy-sics建立了用于求解温差发电系统温度场分布的瞬态计算流体力学(computational fluid dynamics, CFD)模型和用于研究温差发电模块瞬态响应特性的分析模型,提出了混合瞬态CFD-分析模型,并经过瞬态试验验证.结果表明:由于热惯性的影响,TEG系统的转化效率会出现一个瞬时的较高值;相较于尾气温度和质量流量的瞬态波动,热电半导体的热端温度和冷端温度会存在时滞;在美国环保局的高速公路燃油经济性测试(highway fuel economy test, HWFET)模式循环工况下,瞬态模型求解得到整个温差发电系统的平均输出功率、平均转化效率分别为35.63 W和3.40%,瞬态模型的输出电压平均误差为6.41%;该模型能够以较高的精度及较短的计算时间预测温差发电系统在瞬态热源激励下的瞬态响应特性.

铁路货车牵引梁振动频响特性分析

铁路货车牵引梁是轨道车辆运行过程中的重要系统部件,该部件受结构振动影响显著。通过有限元理论和频响理论相结合进行牵引梁有限元分析,基于模态叠加法对牵引梁做频率响应分析,获取牵引梁的变形频响曲线,同时关注固有频率对频响函数峰值的影响,从而使得频响分析结果更为准确。

血清炎性细胞因子CRP、SAA、IL-6水平与首发脑梗死患者睡眠特征的相关性分析

目的分析首发急性脑梗死患者的炎症标志物C反应蛋白(C-reactive proten,CRP)、血清淀粉样蛋白A(serum amyloid protein A,SAA)、白细胞介素-6(interleukin-6,IL-6)水平与主观睡眠特征的相关性。方法前瞻性连续选取2022年5月~2023年4月阜阳市人民医院神经内科收治的113例首发脑梗死患者为研究对象,根据匹兹堡睡眠质量指数(Pittsburgh sleep quality index,PSQI)评分结果分为失眠组(PSQI评分>7分)和非失眠组(PSQI评分≤7分)。比较两组患者的一般人口学资料及CRP、SAA、IL-6水平、汉密尔顿焦虑量表(Hamilton anxiety scale,HAMA)、汉密尔顿抑郁量表(Hamilton depression scale,HAMD)评分差异,采用偏相关分析分析3个血清标志物与PSQI各效应因子之间的相关性。结果两组患者的年龄、性别、基线NIHSS评分、mRS评分比较,差异无统计学意义(P>0.05)。失眠组HAMD评分(z=-3.993,P<0.001)、HAMA评分(z=-3.806,P<0.001)和CRP、IL-6、SAA(P<0.001)均显著高于非失眠组。两组间高脂血症病史差异有统计学意义(z=5.913,P=0.015)。多因素Logisitic回归分析结果显示,CRP(OR=1.55,P<0.01),HAMD评分、HAMA评分及高脂血症均是首发脑梗死患者慢性失眠的独立危险因素,HAMD评分较HAMA评分相比影响更大(OR:1.10 vs 1.04)。偏相关分析结果显示,IL-6、CRP水平与PSQI总分存在显著相关性(P<0.05),而SAA水平与PSQI总分不存在显著相关性(P>0.05)。IL-6水平与睡眠质量(r=0.231)、睡眠效率(r=0.322)、睡眠时间(r=0.221)呈正相关。SAA水平仅与睡眠效率(r=0.242)呈正相关,而CRP水平与入睡潜伏期(r=0.194)、睡眠时间(r=0.247)、睡眠效率(r=0.225)呈正相关。结论首发脑梗死伴随失眠症状的患者存在炎症标志物CRP、IL-6、SAA水平升高,且与失眠的严重程度相关。而CRP、IL-6水平与睡眠特征的相关性分析中有较好的一致性。

薄荷茉莉酸受体McCOI1a基因的克隆与表达模式分析

【目的】茉莉酸(jasmonic acid,JA)受体COI1在调节植物生长发育、逆境响应方面具有重要作用。克隆薄荷McCOI1a基因,并分析其蛋白特征与表达模式,为薄荷分子育种提供基因资源。【方法】基于转录组数据从薄荷叶片中克隆McCOI1a,并通过生物信息学分析、烟草叶片瞬时表达、实时荧光定量PCR技术对McCOI1a的蛋白特性、亚细胞定位、基因表达模式进行分析。【结果】McCOI1a基因全长1842 bp,编码613个氨基酸;McCOI1a蛋白具有保守的F-box和LRR结构域,与丹参SmCOI1蛋白同源性最高;亚细胞定位结果显示McCOI1a蛋白定位于细胞核;McCOI1a在不同组织中均有表达,在根中表达量最高,在叶序中表达呈逐渐上升的趋势;在叶片中,McCOI1a在MeJA、干旱、NaCl、AlCl3、CdCl2、CuCl2处理下的表达呈不同程度的上调,并且AlCl3处理下其上调最明显,表达量最高可达1206倍;在根中,McCOI1a的表达在CuCl2处理下呈先下调而后上调的模式,在其余处理下,McCOI1a的表达都呈现出不同程度的下调。【结论】McCOI1a响应MeJA和非生物逆境胁迫,可能在调控薄荷生长发育、逆境响应方面发挥重要作用。

直升机超临界尾传动轴干摩擦阻尼器碰摩响应边界特性分析

为最大化提高直升机功重比,越来越多的直升机设计中应用了超临界尾传动系统,这一系统会导致跨临界振动的产生。安装干摩擦阻尼器是一种常见的抑制直升机尾传动轴跨临界剧烈振动的方法。以某装有干摩擦阻尼器的尾传动轴为研究对象,建立控制方程,并分析系统在传动轴偏心激励下各类碰摩响应的边界特性。建立传动轴/阻尼器系统的非线性控制方程;依据扫频获得系统典型碰摩响应特征,使用解析法针对无碰摩响应求解碰摩发生边界,并对同频全周碰摩响应求解其稳定性条件的边界;通过Runge-Kutta法验证了所推导的响应边界,并探讨了响应边界与系统参数的影响关系。

天然不含节竹管在轴向压缩冲击载荷下冲击响应与吸能特性的数值分析

天然不含节竹管在工程中应用较广,研究此类天然薄壁管结构的抗冲击能力具有重要的意义。利用分离式霍普金森压杆(split Hopkinson pressure bar, SHPB),研究天然竹管的抗冲击性能并进行有限元分析。在ABAQUS中应用三维Hashin和Puck单向纤维复合材料失效准则,结合应变率效应对强度的修正建立竹管本构模型,对冲击载荷下的天然不含节竹管进行模拟,得到的动态应力-应变曲线和破坏模式与SHPB实验接近,验证有限元模型的准确性。结果表明:实验与模拟的极限抗压强度误差最小为2.19%、最大为8.68%;在不同的冲击压缩载荷下,竹管出现端面压溃、沿轴向劈裂等破坏形式;竹管外壁节点处的位移、速度和加速度响应均随冲击载荷的增加而增加;随冲击载荷升高,入射能、反射能、吸收能和比吸能随时间均呈上升趋势,透射能随时间变化不大;不含节竹管的峰值载荷远低于薄壁圆管GFRP (glass fiber reinforcement plastic),但比吸能较为接近,说明不含节竹管并不适用于需承受大冲击能量的高速冲击防护领域。初步结果可为竹管用于工程结构防护给予理论参考。