我国柴油轿车的发展现状及展望

随着汽车工业的不断发展，轿车动力柴油化已成为行业发展的必然。总结了我国柴油轿车的发展现状，指出了柴油轿车的优势，论述了制约柴油轿车发展的因素，提出了促进柴油轿车未来发展的几点建议。     

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。     

广东省稻菜轮作区中牛筋草对十种除草剂的抗性水平及靶基因序列分析

为明确广东省稻菜轮作区中牛筋草对10种常用除草剂的抗性水平及抗性分子机制,采用整株生物测定法测定广东省稻菜轮作区内8个牛筋草种群P1～P8对草甘膦、草铵膦和乙酰辅酶A羧化酶(acetyl-CoA carboxylase,ACCase)抑制剂类等10种除草剂的抗性水平,并进一步分析P1和P8种群相关靶标酶基因5-烯醇丙酮酰莽草酸-3-磷酸合酶(5-enolpyruvyl-shikimate-3-phosphate synthase,EPSPS)、谷氨酰胺合成酶(glutamine synthetase,GS)和ACCase的部分功能区序列特征。结果显示,牛筋草P1～P8种群对草甘膦抗性指数为敏感种群的5.9倍～17.7倍,其中P8种群对草甘膦的抗性水平最高;8个种群对草铵膦也产生了不同程度的抗性,抗性指数为敏感种群的2.3倍～14.2倍,其中P1种群抗性最高。牛筋草P1和P8种群均对ACCase抑制剂类除草剂精喹禾灵、氰氟草酯和噁唑酰草胺产生了交互抗性;P1种群ACCase基因在第2 041位氨基酸处发生突变,该突变在牛筋草种群中首次发现;而P8种群ACCase基因则在第2 027位氨基...     

Assessment of microbial biocontrol agent (BCA) viability to mechanical and thermal stress by simulating spray application conditions

Background

In order to improve the biological control agent (BCA) efficacy, stress factors threatening the viability of microorganisms during spray application need to be determined. The effect of spray mixture temperature and exposure time on Trichoderma harzianum T 22 and Bacillus amyloliquefaciens QST713 viability were tested. Concurrently the combined effect of mechanical and thermal stress effect on BCA viability were tested at two initial spray mixture temperatures (14 and 25 °C) by simulating a spray application using airblast sprayers featured by different tank capacity and a spray liquid circuit (without and with hydraulic agitation system). To assess the BCA microorganism viability, spray mixture samples were collected at time intervals along trials and plated to count the colony forming units (CFU).

Results

The critical temperature threshold that inhibited BCA viability was 35 °C with 30 min of exposure. The sprayer type, the initial temperature of the spray mixture and the temperature increment during the trials significantly decreased the number of CFU recovered. When simulating a spray application, the spray mixture temperature increase rate was determined mainly by the residual amount of spray mixture in the tank. Even if the tank capacity does not substantially affect the final temperature reached by the spray mixture, the higher residual spray mixture in bigger tanks can expose the BCAs for a longer time to critical temperatures.

Conclusions

Experimental trials allowed us to identify the effect of factors affecting the viability of tested BCAs, providing information about the actual chance to guarantee the biological efficacy of BCA treatments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control

The application of pesticides is not simply delivering chemicals to the target area. It also involves considering the negative aspects and developing strategies to deal with them during the application process, to ensure the maximization of pesticides use efficiency and the maintenance of the ecosystem. Unmanned aerial vehicle (UAV) sprayers demonstrate unique advantages compared to traditional ground sprayers, particularly in terms of maneuverability and labor intensity reduction, showed great potential for chemical application in pest control. It is undeniable that there exist challenges in the practice of UAV spraying, such as higher potential risks of pesticide drift or pathogen transmission, uncertainty canopy deposition for different crops, and unexpected leaf breakage induced by downwash flow. Maximizing the utilization of downwash flow while avoiding lateral air movement outside the intended target crop area is a major issue for chemical application with UAV sprayers, particularly in light of the increasingly apparent consensus on the need for enhanced environmental protection during the chemical application process. It must be considered that the operation strategy in different scenarios and for different crop targets is not the same, unique requirements should be given on nozzle atomization, flight parameters, adjuvants and aircraft types in specific working situations. In future, the implementation of spray drift prediction, technical procedures development, and other solutions aimed at reducing pesticide drift and improving deposition quality, is expected to promote the adoption of UAV sprayers by more farmers. © 2023 Society of Chemical Industry.     

FLUENT软件及其在植保机械方面的应用

FLUENT软件是流体力学中通用性较强的商业软件之一，由于FLUENT软件的应用，节省了大量的人力和物力。对实际应用有重大的指导作用。为此，通过简述FLUENT在植保机械方面的应用实例，提出了FLUENT在植保机械方面的发展前景。     

功能性杂粮膨化食品的研制

选用苦荞、燕麦、杂豆等山西特色杂粮为主要原料,有针对性地强化苦荞的黄酮、燕麦膳食纤维等功能性营养因子,研制出可降低血脂、调节血压和润肠通便等专用系列杂粮膨化保健食品。