基于ASP.NET技术网络教学平台的设计

研究并设计了一个基于ASP.NET技术的网络教学平台,便于教师的教与学生的学,实现以学生为主体、教师为主导的交互的网络教学环境。     

以信息服务推动城乡一体化进程的思路探讨

信息作为与物质、能量同等重要的战略性资源,在城乡一体化的发展中起着越来越重要的作用。高校图书馆可凭借信息资源优势、人才优势、服务优势推送信息服务,推进城乡一体化进程。对推送信息服务的思路进行了探讨,提出了推进信息服务的途径。     

玉米杂交种辽单43的选育思路及技术上的创新

优质玉米杂交种辽单43是辽宁省农业科学院以自选系辽4584为母本,自选系辽5088为父本组配而成的玉米杂交种。母本来源于四个自交系（铁7922×沈5003）×（辽5011×辽8713）选系,父本来源于美国杂交种78479选系。文章详细剖析了品种来源及母本、父本的选育过程。并对辽单43使用聚合杂交技术重组优良基因和利用新的杂交优势模式等技术创新方面做了分析。希望能给广大育种者提供新的思路和方法。     

Studies on hollownesss regulation and properties of crosslinked hollow phenolic fibers

The hollowness of crosslinked hollow phenolic fibers was regulated successfully from 9 % to 80 % by adjusting the curing temperature of the partially crosslinked fibers. The partially crosslinked fibers was studied in detail by mass gained, tensile strength, solvent dissolution, SEM, IR, and TG analysis, and the prepared hollow phenolic fibers with different degrees of hollowness were characterized with SEM, tensile strength, TG-DSC and TG-MS. The results show that the factor determining the hollowness is the crosslinked extent of the partially crosslinked fibers and the hollow fibers with different degrees of hollowness have similar crosslinkage, mechanical properties and thermal stability.     

DNA Barcoding:An Effective Tool for Species Identification of Lepidopteran Oak Pests

[Objective] The paper was to improve the efficiency and accuracy of early forecast of Lepidopteran oak-infesting pests.[Method] DNA barcoding technique was established for quick species identification using mitochondrial cytochrome C oxidase subunit Ⅰ(COⅠ) as the standard gene.This barcoding technique was used to amplify and sequence genomic DNA samples from eggs and pupae of 11 species of Lepidopteran pests collected from oak.[Result] The DNA barcoding standard genes of 594-708 bp were determined from eggs and pupae of Lepidopteran insects.There were differences of 0-2 bases in DNA barcode sequences between conspecific eggs and pupae,with the sequence identity of 99.7%-100%.The average content of A,T,G and C of DNA barcode sequences from Lepidopteran insects were 30.7%,38.5%,14.9% and 15.9%,respectively.The obtained DNA barcode sequences had 91.4%-100% identity and 0-8.6% difference degree with GenBank-deposited DNA barcode sequences from organisms of the genetically-closest relationship.Among them,DNA barcode sequences from egg and pupa samples of 10 Lepidopteran insects(No.1-20) had 99%-100% identity and 0-1.0% difference degree with homologous sequences in GenBank database,while the remaining samples(No.21-22) had high difference degree(8.6%) with homologous sequences.[Conclusion] The established DNA barcoding technique is an effeetive tool for species identification of Lepidopteran pests using genomic DNA from eggs and pupae of Lepidopteran insects.     

Effect of LDPE microplastics on chemical properties and microbial communities in soil

The accumulation of plastics in the soil ecosystem poses an increasing environmental concern worldwide. However, little is known about the effect of plastic concentrations on soil properties and soil biota. In this study, we investigated the effect of low-density polyethylene (LDPE) microplastics (MPs) on the chemical and microbial properties of agricultural soil using a set of microcosm experiments. The soil was incubated for 100 days with LDPE at concentrations of 0%, 0.1%, 1%, 3%, 5%, and 7% at 25°C with 70% water-holding capacity. Along with soil chemical analysis, we conducted an analysis of soil microbial properties on the first day and again after 100 days of incubation. LDPE concentrations of ≥1% significantly (p < .05) decreased the pH but increased the electrical conductivity of the soil in comparison with the control (0% LDPE at 100 days). Increasing the LDPE concentration did not affect the soil exchangeable cation content or the available Pb concentration. Firmicutes were the most abundant phyla in the soil on the first day, whereas Proteobacteria, Firmicutes and Actinobacteria became dominant in all treatments after 100 days. An increasing LDPE concentration increased the abundance of Actinobacteria and decreased Proteobacteria. Principal component analysis demonstrated that only 7% LDPE was positively correlated with Actinobacteria, indicating that higher concentrations of LDPE contributed to the growth of this phylum. The findings of this study imply that MP contamination could affect soil chemical properties and microbial activity and that these effects primarily depend on MP concentrations in soil.     

SWAT模拟耕作方式与盐分对区域土壤氮运移及作物产量影响

耕作方式与土壤盐渍化是影响河套灌区氮素流失及作物产量的重要因素。明确不同耕作方式与盐渍化水平下硝态氮运移量及作物产量的变化,可为制定合理的灌区耕作措施及盐渍化治理方案提供理论依据,对于揭示灌区氮素流失控制及不同作物增产潜力具有重要意义。该研究基于验证后的SWAT（Soil and Water Assessment Tool）模型,以河套灌区2种主要土壤类型为研究对象,设置不耕作（指不添加耕作管理,CK）、免耕（T1）、少耕（T2）、常规春耕（T3）和模板犁（T4）5种耕作处理,非盐化土（S1）、轻度（S2）、中度（S3）、重度（S4）4种盐分水平,研究耕作方式与土壤盐分对灌区产水量、作物吸氮量、硝态氮淋溶量及运移量、作物产量的影响。结果表明：耕作方式与土壤盐分对区域总产水量、作物吸氮量、硝态氮淋溶量、硝态氮运移及作物产量均有显著影响（P<0.05）。其中,区域产水量、硝态氮淋溶量、不同水文路径（地表、侧向和地下径流）硝态氮运移量及小麦产量均随耕作混合深度与混合效率的增加逐渐减少;作物吸氮量、玉米与葵花产量均随耕作混合深度与混合效率的增加逐渐增加。与CK相比,模板犁耕作作物吸氮量平均增加11.78%,硝态氮淋溶量平均减少16.5%,有效降低了土壤养分流失和地下水污染。增加土壤盐分通过降低土壤层有效持水量,显著增加了区域总产水量、硝态氮淋溶量（草甸盐土除外）及硝态氮地下运移量,减少了作物吸氮量和作物产量。与非盐化土相比,重度盐化土处理小麦、玉米、葵花产量平均显著减少19.15%、27.31%、26%（P<0.05）。增加土壤盐分相比转变耕作方式更能影响区域产水量、土壤养分和作物产量。因此,为更好解决灌区污染严重和作物产量下降等问题,仍需将区域土壤盐渍化防控与治理放在首要位置。     

液压机械无级变速装载机工况在线识别方法

液压机械无级变速装载机发动机转速与车速解耦,具有节油、高效的优点,为了解决其工况繁多、动力匹配问题,以某液压机械无级变速装载机为研究对象,基于液压机械状态参数开展了装载机负载估计理论分析和仿真,建立了负载估计模型,仿真结果表明该方法能准确估计液压机械段内负载,结果偏差在±4.69%以内。在负载估计方法基础上,建立液压机械无级变速装载机工况识别模型以及整车仿真模型,通过理论分析与仿真相结合的方法,得到液压机械无级变速装载机在线工况识别方法及对应速比控制策略。仿真结果表明,该方法能够准确识别装载机当前工况,满足实际工程要求,所提出的分工况速比控制策略与常规策略相比,单作业循环时间减少了2.43 s,作业效率提高了4.42%,总油耗降低了1.41%。研究为装备液压机械无级变速器的装载机及拖拉机等提高生产效率及燃油经济性提供了途径。     

勺链式大蒜播种机漏取种检测与补种装置设计及试验

针对勺链式大蒜播种机在取种过程中的漏取问题,该研究设计了一种以激光传感器、转勺式补种器、补种箱为核心的大蒜漏取种检测与补种装置,并搭建了试验台.利用漫反射激光传感器对取种情况进行检测,根据输出脉冲判断取种勺是否漏取种,设计了以STM32处理器、电磁离合器为核心的漏取种检测与补种控制系统.为得到取种勺漏取蒜种时的临界脉冲...