液压升降折叠宽幅喷杆喷架的结构设计

针对目前植保机械中所使用的喷杆喷架稳定性差、折叠伸展需要人工辅助等问题,设计出了一种液压升降折叠宽幅喷杆喷架。对喷杆喷架的升降装置、90°液压油缸折叠机构、180°液压油缸折叠机构和整体宽幅喷架进行了理论分析和结构设计,并建立了关键部件的三维模型。通过田间试验验证了该装置设计方案的合理性,为研发先进适用、具有自主知识产权的液压升降折叠宽幅喷杆喷架奠定了基础。     

基于外碾削立式碾米机的离散元法仿真分析

引入离散元仿真技术对碾米机械进行仿真研究,旨在探索碾米机在碾白过程中的碎米机理。通过模拟大米在输送过程来获得速度、运动轨迹等数据,由图表等方式输出模拟结果,可以看到米粒群绕着碾辊做螺旋形前进的运动规律。该技术在粮食机械设计系统的研究中具有重要的推广意义,可为碾米机优化设计提供理论参考,也为其他农业物料精确定量分配提供了一种新的方法。     

管理节水模式在农业节水中的应用研究

管理措施可以促进节水工程的高效运行,提高农民的节水积极性,使节水工程能够真正的节水。在节水工程的基础上,针对不同类型的节水工程探索相对的管理模式:地下低压管道水网建设节水工程对应的管理模式为"中心+联合会+用水户协会"管理模式;地上输水渠道水网建设节水工程主要管理模式为水管站式管理。在实地调研的基础上,分析了德州市两种管理措施在节水工程中的作用,总结了它们的主要特点及节水效果:"中心+联合会+用水户协会"可以提高工程节水效率,使水利用系数达到0.95以上。针对德州市不同的节水工程分析其管理措施,可为未来农业节水机制的探讨提供理论依据。     

Research Progress on Action Mechanism of Animal Anti-parasitical Drugs

Animal anti-parasitical drugs are mainly used to prevent and control animal parasitosis, and also an effective way to protect the healthy development of animal husbandry and public health security.The efficacy of anti-parasitical drugs depends on the interaction between drug molecular and different target tissues and target cells of parasite or animal.Because of the variety of anti-parasitical drugs, the anti-parasitical mechanisms are complex.With the development of new anti-parasitical drugs and the depth of scientific research, especially the development of chemical synthesis and biological pharmaceutical technology, the variety and quantity of anti-parasitical drugs constantly increase.With the discovery of new drug structure and its action target, the study on the mechanism is constantly deep.The author mainly summarized the research progress on action mechanism of anti-parasitical drugs.     

动物脂肪沉积程序化及精氨酸的调控作用

脂肪的过度沉积常伴随着胰岛素抵抗、Ⅱ型糖尿病等代谢病症,既危害人类健康,带来经济负担,也会在农业生产中影响畜牧产品的质量。脂肪的沉积,始于胚胎期脂肪组织的发育,是一系列程序化作用的结果。脂肪沉积受多方因素影响,营养干预可以通过胚胎环境中的糖皮质激素浓度、线粒体功能、表观遗传、食欲中枢发育等方面影响胚胎脂肪沉积程序化。论文阐述了动物出生前后营养状况对脂肪沉积程序化的作用,对脂肪沉积的机制进行了初步探讨,并介绍了精氨酸营养在脂肪沉积中的应用。饮食中添加精氨酸为治疗脂肪过度沉积,提高畜牧生产水平,改善人类生活质量,开拓了新的思路。     

20份欧洲型黄瓜种质资源的半致死温度与耐热性研究

为探讨不同欧洲型黄瓜种质资源对高温的适应性差异,为耐热种质资源筛选及耐热机理的深入研究提供理论和实践依据,以20份欧洲型黄瓜的叶片为材料,设置6个高温处理,以室温为对照,测定浸提液电导率值并计算相对电导率,通过拟合Logistic方程,计算半致死温度(LT50)。试验结果表明,随着温度升高,相对电导率呈"S"型曲线,且相对电导率与处理温度存在显著的直线相关关系,通过计算"S"型曲线拐点求得20份欧洲型黄瓜的半致死温度在45~51℃,其中33-2的半致死温度最高,达到50.09℃,37-1的半致死温度最低,为45.82℃。20份欧洲型黄瓜的耐高温能力由强到弱依次为33-275-232-233-111-231-209-236-276-136-137-210-135-276-211-143-235-175-132-137-1。因此,半致死温度可作为评价欧洲型黄瓜耐热性的一个可靠指标。     

食品安全与食品低温流通中的温度监控

食品的温度监控是一种有效的保证食品安全及保持冷藏链完整的手段,对冷冻冷藏食品在低温流通过程中实行温度监控是非常有必要的。目前,我国冷藏运输中的温度管理情况并不乐观,消费者获得的货物通常不能达到预计的要求。要解决这一问题,必须要借助于时间-温度指示器等来对其整个运输过程进行温度监控。本文对温度立法的必然性和前景,温度监控的重要性、原理以及在冷藏运输中的应用作了较详尽的介绍,并列举了几种国外时间-温度指示器的工作原理。     

Changes in the herbicide sensitivity and competitive ability of Abutilon theophrasti over 28 years: Implications for hormesis and weed evolution

BACKGROUND

The potential of weed species to respond to selection forces affecting the evolution of weedy traits such as competitive ability is poorly understood. This research characterized evolutionary growth changes in a single Abutilon theophrasti Medik. population comparing multiple generations collected from 1988 to 2016. A competition study was performed to understand changes in competitive ability, and a herbicide dose–response study was carried out to assess changes in sensitivity to acetolactate synthase-inhibiting herbicides and glyphosate over time.

RESULTS

When grown in monoculture, A. theophrasti biomass production per plant increased steadily across year-lines while leaf number decreased. In replacement experiments, A. theophrasti plants from newer year-lines were more competitive and produced more biomass and leaf area than the oldest year-line. No clear differences in sensitivity to imazamox were observed among year-lines. However, starting in 1995, this A. theophrasti population exhibited a progressive increase in growth in response to a sublethal dose of glyphosate (52 g a.e. ha⁻¹), with the 2009 and 2016 year-lines having more than 50% higher biomass than the nontreated control.

CONCLUSION

This study demonstrates that weeds can rapidly evolve increased competitive ability. Furthermore, the results indicate the possibility of changes in glyphosate hormesis over time. These results highlight the importance of the role that rapid (i.e., subdecadal) evolution of growth traits might have on the sustainability of weed management strategies. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

3-RPS并联机构奇异位形及工作空间研究

提出一种求解并联机构无奇异位形工作空间的方法。通过分析3-RPS并联机构在奇异位形时动平台的微分运动与结构约束及关节约束的关系，得到机构奇异位形判别方程和奇异位形曲面方程。探索了工作空间边界，综合分析了机构奇异位形与工作空间的关系。合理选择机构结构参数和关节变化范围，得到了无奇异位形的工作空间。     

发展农业机械化,建设社会主义新农村

现代化的农机装备作为先进的劳动工具,推动了生产力和文明社会的快速发展。建设社会主义新农村,农业机械化既是充要条件,又是必要条件;农业机械化是实现生产发展、生活宽裕、村容整洁、环境和谐的手段、条件、保证。没有农业的机械化,不可能有真正意义上的社会主义新农村建设。