Method for secondary spring load equalization of railway vehicles with two-stage spring suspension: Modeling and optimal regulation

To ensure running safety,the secondary spring loads of railway vehicles must be well equalized.Due to the coupling interactive effects of these hyper static suspended structures,the equalization adjustment through shimming procedure is quite complex.Therefore,an effective and reliable method in application is developed in this paper.Firstly,the best regulation of spring load is solved based on a mechanical model of the secondary suspension system,providing a target for actual adjustment.To reveal the relationship between secondary spring load distribution and shim quantity sequence,a forecasting model is constructed and then modified experimentally with consideration of car body’s elastic deformation.Further,a gradient-based algorithm with a momentum operation is proposed for the load optimization.Effectiveness of the whole method has been verified on a test rig.It is experimentally confirmed that this research provides an important basis for achieving an optimal regulation of spring load distribution for multiple types of railway vehicles.

Effects of Growth Regulators on Biomass and the Production of Secondary Metabolites in Peppermint (<i>Mentha pi-perita</i>) Micropropagated <i>in Vitro</i>

The effects of plant growth regulators on peppermint (Mentha piperita) cultured in vitro were studied for the purpose of maximizing growth and essential oil production in micropropagated plants. The basal medium was experimentally supplemented with the auxin 4-indol-3-ylbutyric acid (IBA) and the cytokinin 6-benzylaminopurine (BAP) individually and in combination. Supplementation with BAP alone resulted in the highest values for root length, root dry weight, shoot length, and numbers of nodes, leaves, and ramifications. Treatment with IBA alone or with IBA + BAP resulted in a ~50% increase in shoot fresh weight. The production of secondary metabolites was affected only by the addition of cytokinin, which resulted in a ~40% increase in the total yield of essential oils (EOs). Similar trends were observed for yields of the major EO components (menthone, menthol, pulegone, and menthofuran). Our findings demonstrate that the application of growth regulators increases EO production and biomass concomitantly in an herbaceous species rich in commercially valuable terpenes.

Expression of yeast silencing information regulator 2 in secondary injury of intracerebral hemorrhage

Objective:to investigate the expression of yeast silencing information regulator 2(Sirt2)in the secondary injury of intracerebral hemorrhage(ICH).Methods:twelve Sprague Dawley(SD)rats were randomly divided into a sham group and an ICH group,with six rats in each group.A rat model of ICH was established by injecting collagenase type IV into the right striatum of the rats.The expression of Sirt2 was measured by Western blot and immunohistochemistry after ICH.Result:the behavioral score of the ICH rats was the lowest at 48 h after the operation;therefore the rats at 48 h after surgery were selected as the model rats.The expression of Sirt2 was significantly higher in the striatal tissue of the ICH rats compared with the sham group(P<0.05).Conclusion:the expression of Sirt2 around hematoma in ICH rats decreases,and Sirt2 is expected to become a new target for ICH treatment.

Regulation of the Warsaw Stock Exchange： History and Operating Rules

The aim of this article is to present the principles of the operation of the Warsaw Stock Exchange （WSE）, which is the most important institution of the capital market in Poland. The article is an attempt to explore the history and structure of the exchange and its investment possibilities in order to understand the number of existing security features which make cooperation with this institution-with appropriate assumptions and diversification-an activity providing profits to potential investors who are aware of its operating rules. This topic deserves a historical outline because of the socialist past and the current status of the WSE, now called the most dynamically growing capital market in Central and Eastern Europe.

Optimal Cooperative Secondary Control for Islanded DC Microgrids via a Fully Actuated Approach

DC-DC converter-based multi-bus DC microgrids(MGs) in series have received much attention, where the conflict between voltage recovery and current balancing has been a hot topic. The lack of models that accurately portray the electrical characteristics of actual MGs while is controller design-friendly has kept the issue active. To this end, this paper establishes a large-signal model containing the comprehensive dynamical behavior of the DC MGs based on the theory of high-order fully actuated systems, and proposes distributed optimal control based on this. The proposed secondary control method can achieve the two goals of voltage recovery and current sharing for multi-bus DC MGs. Additionally, the simple structure of the proposed approach is similar to one based on droop control, which allows this control technique to be easily implemented in a variety of modern microgrids with different configurations. In contrast to existing studies, the process of controller design in this paper is closely tied to the actual dynamics of the MGs. It is a prominent feature that enables engineers to customize the performance metrics of the system. In addition, the analysis of the stability of the closed-loop DC microgrid system, as well as the optimality and consensus of current sharing are given. Finally, a scaled-down solar and battery-based microgrid prototype with maximum power point tracking controller is developed in the laboratory to experimentally test the efficacy of the proposed control method.

Isolation and characterization of the secondary wall-related SND1 gene in hawthorn

Secondary wall-associated NAC domain protein1 （SND1） is a key regulator directly regulating the expression levels of MYB46 and MYB83 in the regulation network for secondary wall synthesis, especially in plant fibres. In this study, a SND1 gene was isolated from hawthorn （Crataegus pinnatifida） and named as CpSND 1 because it has a conservative N-terminal DNA- binding domain with AtSNDI. Arabidopsis plants overexpressing CpSND1 had similar phenotypes as plants overexpressing AtSND1, including inhibited growth, upward-curling leaves, sepal dysplasia and sterility. In addition, overexpressing CpSNDI in Arabidopsis also induced the expression of downstream genes, including lignin, cellulose and xylan biosynthesis genes as well as MYB genes. Our results provided functional information of CpSND1 for future genetic engineering in hawthorn.

Effects of Waterlogging Stress on the Physiological Characteristics and Secondary Metabolites of Herbaceous Peony (<i>Paeonia lactiflora</i>Pall.)

Herbaceous peony is an ornamental plant with medicinal properties. Waterlogging can affect its yield and quality as it grows and matures. In this study, we subjected “Taohuafeixue”, “Yangfeichuyu” and “Hongxiuqiu” herbaceous peony varieties to a simulated waterlogging stress treatment and investigated the effects of waterlogging on their physiological characteristics and the secondary metabolite contents in their leaves and roots. Short-term waterlogging caused the leaves to turn yellow or red and the roots to turn black. The stele and the cell wall of the endothelial cells thickened, and the cortical cells enlarged. Waterlogging did not significantly change plant height, leaf length, and leaf area;however, it significantly decreased the root-shoot ratio of “Yangfeichuyu” and “Hongxiuqiu” varieties. The activity of antioxidant enzymes and the content of osmotic regulators increased under waterlogging. After short-term waterlogging stress treatment, the content of paeoniflorin and albiflorin increased in the roots of “Taohuafeixue” and “Yangfeichuyu”, and the content of benzoylpaeoniflorin increased in the root of “Hongxiuqiu”. The content of gallic acid and total flavonoids increased in the leaves of “Taohuafeixue” and “Yangfeichuyu”. After the waterlogging, paeoniflorin and benzoylpaeoniflorin increased in the autumn root of “Hongxiuqiu”. This study expands our knowledge about the medicinal properties of herbaceous peony and informs about its production and cultivation under waterlogged conditions.

多风电场支撑电网频率稳定的动态差异化时序协同控制策略

针对大规模风电接入带来的系统调频能力不足和调频能量透支引发的频率二次跌落问题,提出一种多风电场动态差异化时序协同的频率支撑控制策略。首先,阐述综合惯量控制下的风电调频原理,基于能量守恒理论分析频率响应阶段风电场群的动能变化过程,揭示多风电场调频时序对调频效果的影响机理。然后,考虑多风电场群同时调频引发的频率二次跌落风险,从场站交互视角逆向设计风电场群调频时序和任务分工,并依据风电实时调频能力动态调整投入顺序,以保证初期过程惯量安全需求,并提升频率最低点、抑制风电场群退出调频导致的系统频率严重二次跌落。最后,通过3机9节点测试系统和某实际电网算例对所提控制策略进行仿真分析,结果验证了所提策略的有效性和实用性。

考虑系统频率安全稳定约束的风储联合频率响应控制策略

为提升风-储联合运行系统的动态频率稳定性能,针对目前调频控制策略未充分发挥风电机组频率调节能力、无法适应负荷扰动过大情况以及转子转速恢复阶段存在频率二次跌落的问题,提出一种考虑系统频率安全稳定约束的风储联合频率响应控制策略。在惯量响应阶段结合转速约束和频率指标自适应调整虚拟惯量和下垂控制系数,在转子转速恢复阶段利用负指数函数动态调整转速恢复过程中功率参考值,避免频率的二次跌落。将风电机组与储能电池结合,引入频率稳定域概念,利用储能电池扩展频率稳定域边界,进一步提升风储联合系统的抗负荷扰动能力和频率稳定性。最后对风储联合调频策略进行仿真,结果表明在不同风速和不同负荷扰动下,所提控制策略能充分发挥风电机组频率响应控制能力的同时,避免了频率二次跌落,提升了电网频率安全稳定性。

避免频率二次跌落的风储联合调频控制策略

风电高渗透电力系统中,风机释放转子动能参与频率响应改善系统频率稳定性,但存在欠响应支撑效果不足或过响应导致系统频率二次跌落现象。储能响应不受时空因素影响,通过整定储能响应参数,可提升风电频率响应的有效性。该文首先基于统一结构模型分析系统频率二次跌落与风机控制策略之间的作用机理。其次,整定充分利用风机频率响应能力及避免系统频率二次跌落的风电机组频率响应系数。然后,引入频率稳定裕度概念,并基于关系矩阵整定的储能最小出力,等效扩展系统频率稳定裕度。基于以上分析,综合考虑时空因素对系统频率响应影响,提出一种多时间尺度下避免频率二次跌落的风储联合调频控制策略。最后,基于DIgSILENT搭建风电高渗透4机4区系统进行仿真验证。结果表明,所提控制策略在不同风速下兼顾风机频率响应能力,同时避免频率二次跌落,提高全网频率安全稳定裕度。

风电机组自适应步进惯量控制策略

若风电机组参与调频时采用步进惯量控制(stepwise inertial control,SIC)策略,其退出调频时有功快速下降可能会引发系统频率二次跌落(frequency second drop,FSD)问题。已有文献中一类改进的SIC策略通过减小风电机组退出调频后有功下降阶段的斜率来应对FSD问题,然而该类改进的SIC策略使得风电机组在退出调频后其有功需要一段时间才会小于风能捕获,在此期间转子转速会继续下降并有可能低于转速下限,危及风电机组运行安全。文章对这一类改进的SIC策略做了进一步完善,提出了一种风电机组自适应SIC策略,根据风电机组退出调频时的转子转速自适应设置风电机组退出调频后有功下降阶段的斜率,在确保风电机组退出调频后转子转速不会低于转速下限的前提下,最小化FSD的幅度。

从“清激调补”探讨新型冠状病毒二次感染的临证思路

结合新型冠状病毒二次感染的现状,在辨病与辨证、辨分期结合的基础上,提出“清激调补”的中医临证思路。“清”即清除外来邪毒与内生浊物,祛邪外出,是新型冠状病毒二次感染治疗的关键;“调”为调理脏腑,随证治之,是新型冠状病毒二次感染治疗的重要内容;“激”是激发人体正气,调动先天之气补充后天之气以抗邪,“补”即补益气血阴阳,“激”与“补”二者均扶正以祛邪,是促使新型冠状病毒二次感染患者恢复健康的重要手段。

脱落酸及其调控植物次生代谢产物生物合成的研究进展

次生代谢产物是植物长期进化过程中为了适应生态环境产生的天然有机化合物,近年来,随着生物技术的发展,植物次生代谢产物经济以及药用价值愈发引起广泛关注。但一些次生代谢产物因为其复杂的结构和合成路径以及在植物中极低的含量,使其不能低成本大量生产。脱落酸(ABA)作为调控植物生长发育过程中的重要植物激素之一,可以依靠自身的合成与分解、信号传导、激素互作等作用来调控次生代谢产物的合成。文章综述了ABA在生物合成与分解代谢以及信号转导等方面的新进展,归纳了ABA对不同类型次生代谢产物的调控作用,为合理利用植物激素提高植物次生代谢产物的产量提供依据。

事件触发改进一致性算法的孤岛运行多逆变器微电网系统分布式二次调频方法

一致性算法常用于孤岛运行多逆变器并联微电网系统分布式二次调频控制,对逆变器之间通信的实时性要求很高。对此,该文提出基于频率补偿信号的改进一致性算法,基于频率误差越限建立事件触发机制,维持逆变器之间已有的下垂关系不变,实现孤岛运行多逆变器微电网系统二次调频。同时,基于该事件触发机制和李雅普诺夫函数,获得最短触发时间下界,完全避免了在短时间内无限次事件触发现象的发生。最后,采用MATLAB/Simulink针对包含4台逆变器并联运行的孤岛微电网系统算例进行仿真,结果表明,提出的方法相比文献采用的基本一致性算法通信量减少99%以上,最短触发时间间隔延长至数十ms量级;同时,由于该文方法不使用功率微分信号,微电网系统的动态性能更好。

计及电池寿命的储能系统参与二次调频功率分配策略

储能系统辅助火电机组二次调频具有响应速度快、跟踪精度高等优点,但功率分配不当会加速电池寿命衰减,导致运行成本增加,经济效益下降。如何制定合理的储能功率分配策略,在确保调频性能的同时延长电池寿命并提高经济效益,已成为亟待解决的重要问题。首先基于二阶RC等效电路建立储能锂电池的数学模型,采用限定记忆最小二乘递推算法辨识模型参数;随后,在火储联合调频模型的基础上,对基于比例、差额和频率的3种功率分配策略进行了仿真分析;最后,根据江苏某660 MW火电机组的实际运行数据,重点分析了不同策略对系统调频性能、电池寿命及经济性的影响。结果表明,比例分配策略的调频效果最差,且会加速电池寿命衰减;差额分配策略在调频性能上表现优异,但对电池寿命的改善有限;频率分配策略能够有效降低电池更换频率,可提高整体经济效益。总体而言,频率分配策略不仅可提高系统的调频能力,还能最大限度延长电池寿命并优化经济效益,在储能系统辅助火电机组二次调频中具有显著的应用优势。

考虑火电运行平稳性的飞轮储能辅助二次调频控制策略

为解决电网波动剧烈导致的火电机组运行平稳性问题,提出一种考虑火电运行平稳性的飞轮储能辅助二次调频控制策略。首先,建立了超超临界火电机组联合飞轮储能的二次调频控制模型;其次,提出了一种基于多层变增益速率限制的AGC指令非线性分解方法;最后,综合机组平稳性和系统AGC性能设计了适应度函数,借助鲸鱼优化算法(WOA)实现了最优化的速率限制算法参数获取。基于上述方法设计了火储协同二次调频控制策略。以某1000 MW火电机组-飞轮储能联合系统为例进行了仿真验证。结果表明:所提控制策略在不影响系统调频性能的前提下可以使联合系统有效响应系统高频指令,减小了火电机组的动作幅度,提升了机组运行的平稳性。

一种基于有源滤波电路的高PSRR低噪声LDO电路设计

为了减少低压差线性稳压器(Low Dropout Regulator,LDO)电路中的噪声以及输入电压携带的纹波对输出电压精度所带来的影响,提出了一种基于有源滤波思想的优化LDO噪声和电源抑制比(Power Supply Rejection Ratio,PSRR)的电路设计技术,在不考虑功耗以及压差的条件下,采用多级稳压设计以大幅提升LDO的电源抑制比。通过前级LDO电路对输入电压进行稳压,形成二次电源后对后续电路进行供电,同时在后级LDO的基准端加入一级额外的稳压电路进行稳压,并通过低功耗RC滤波器和跨导放大器以减少环路噪声。此外,电路还加入了低噪声前馈电路以及快速启动电路提高LDO的响应速度。基于0.18μm BCD工艺,在5 V输入3.3 V输出,负载电流为10 mA的仿真验证下,测得整体电路在1 kHz时PSRR达到−110 dB,同时在10~100 kHz下其噪声仅为5.3μVrms。同时,通过改变基准端负载电容以及负载电流对LDO的PSRR以及噪声进行仿真,其结果均满足设计需求,有效提高了LDO输出电压的精度。

基于双层协调控制的电池储能参与电网二次调频策略

针对电池储能参与电网二次调频的场景,为了提升电池储能的寿命以及改善调频效果,提出一种基于双层协调控制的电池储能控制策略。在外层控制中,针对储能参与电网调频的时机与深度,分析基于灵敏度计算的阶跃式控制模式对储能出力特性的影响,并提出基于指数函数变换的分配因子平滑式自适应调整策略,在保证调频质量的同时,优化储能出力。在内层控制中,将电池储能系统分为不同充、放电特性的两部分,以减小频繁充、放电切换对电池寿命的影响。提出结合超短期负荷预测的电池储能荷电状态双层模糊优化策略,根据等效荷电状态和负荷变化趋势修正储能分配因子,在维持电网调频质量的前提下优化电池储能的荷电状态,解决在调频过程中因充、放电总能量不均衡而导致的高/低荷电状态极端运行问题,保证电池储能的持续调频能力。基于某电网的实际负荷数据,在MATLAB/Simulink中验证所提策略的有效性。

希望理论护理联合理性情绪调节策略对脑梗死后继发癫痫患者的影响

目的 探讨希望理论护理联合理性情绪调节策略对脑梗死后继发癫痫患者希望水平、心理弹性、应对方式的影响。方法 选取医院2022年6—12月收治的脑梗死后继发癫痫患者65例,根据基本资料具有可比性的原则将患者分为观察组33例和对照组32例,观察组患者给予希望理论护理联合理性情绪调节策略,对照组患者则行理性情绪调节策略。分析并比较两组患者护理前后希望水平、心理弹性、应对方式和神经功能恢复情况。结果 护理前两组患者和他人保持亲密关系、对现实和未来的态度以及采取积极行动各维度评分比较,差异无统计学意义(P>0.05);护理后观察组和他人保持亲密关系、对现实和未来的态度以及采取积极行动各维度评分高于对照组,差异有统计学意义(P<0.05)。护理前,两组患者乐观、自强等各个维度评分差异均无统计学意义(P>0.05);护理后,观察组患者RS-11量表各维度评分均高于对照组,差异有统计学意义(P<0.05)。护理前两组患者面对、回避、屈服三种应对方式评分比较差异无统计学意义(P>0.05);护理后,观察组面对应对评分高于对照组,回避和屈服应对评分低于对照组,差异有统计学意义(P<0.05)。护理前两组美国国立卫生研究院卒中量表(NIHSS)评分比较差异均无统计学意义(P>0.05),护理后观察组NIHSS评分低于对照组,差异有统计学意义(P<0.05)。结论 希望理论护理联合理性情绪调节策略不仅可以提高脑梗死后继发癫痫患者的希望水平,改善患者的心理弹性和应对方式,还可以有效促进患者神经功能的恢复。

Transcriptional Regulation of Secondary Growth and Wood Formation

Secondary growth and wood formation are products of the vascular cambium, a lateral meristem. Although the mechanisms have only recently begun to be uncovered, transcriptional regulation appears increasingly central to the regulation of secondary growth. The importance of transcriptional regulation is illustrated by the correlation of expression of specific classes of genes with related biological processes occurring at specific stages of secondary growth, including cell division, cell expansion, and cell differentiation. At the same time, transcription factors have been characterized that affect specific aspects of secondary growth, including regulation of the cambium and differentiation of cambial daughter cells. In the present review, we summarize evidence pointing to transcription as a major mechanism for regulation of secondary growth, and outline future approaches for comprehensively describing transcriptional networks underlying secondary growth.