户用风光互补发电系统设计与经济评价(简报)

湖区渔民远离电网,获得生活用电是提高渔民生活质量的重要方面,风光互补发电系统的应用是解决离网地区电力供应的一个新的选择。以金湖县宝应湖为例,根据当地风能和太阳能资源,对风光互补发电系统进行设计,在确定风力发电机瓦数为150 W情况下,给其匹配85 WP太阳电池组件能满足用户用电需求,对风光互补发电系统进行成本效益分析,表明该系统在此地区推广有其经济可行性。     

Evaluation of alternate menthol mint (Mentha arvensis L.) based intensive cropping systems for Indo-Gangetic plains of north India

The objective of the study was to determine the profitability and employment-generation potential of different cropping systems involving menthol mint (Mentha arvensis L.) as a component of sequential/intercropping in comparison with the most common paddy–wheat–green gram cropping system. Field experiments were conducted at Lucknow, India (26° 5′ N, 80° 5′ E and 120 m above mean sea level) for three years from July 2004 to June 2007. Menthol mint yielded the maximum fresh shoot biomass and essential oil (21.0 t and 151 kg ha^?1, respectively) grown after sweet basil (Ocimum basillicum)–potato followed by paddy–potato–menthol mint (18.9 t and 136 kg ha^?1, respectively) and maize–mustard–menthol mint (17.7 t and 131 kg ha^?1, respectively). Net returns of all the menthol-mint-based cropping systems were 82.6–354% higher than traditional paddy–wheat–green gram cropping system. Maize–garlic–menthol mint + okra was found to be most profitable (77,200 Rs ha^?1) followed by pigeon pea + sweet basil–menthol mint + okra (76,120 Rs ha^?1). Employment-generation efficiency was much higher in cropping systems involving menthol mint and vegetable crops, the highest (2.21 man days ha^?1 day^?1) being in a maize–cauliflower–onion–menthol mint + okra cropping system.     

Selection in Early Generations of Dried Peas, Pisum sativum L. III. Plot Size and Plot Type

Investigations were carried out to study the effect of different plot sizes and plot types on the performance of peas and to determine plot size and plot type combinations suitable for the reliable evaluation of varietal yield performance realized in commercial stands of pea crops. Four pea varieties were tested in 1981 and 1982 in combinations of plot sizes ranging from 0.25 m2 to 19.50 in2 with plot types either unbordered, bordered with faba beans, surrounded with perforated plastic foil or only central sections of plots harvested (net plots). With decreasing plot size the performance mean as well as the error variance of grain yield and thousand grain weight increased disproportionately. Thus, changes in grain yield were much higher than those for thousand grain weight. The four varieties tested reacted differently to changing plot sizes and as a result, highly significant variety × plot size interactions were found. Although overestimation of grain yield in small plots could be strongly reduced by bordering the plots with faba beans or surrounding them with plastic foil, their suitibility for yield testing was limited by highly significant variety × plot type interactions. Compared to the largest net plot (15 m²) reliable results were still obtained with plot sizes larger than 6.5 m², no matter whether edge effects were eliminated or not. If only a small quantity of seed is available, plots may be reduced even to 1.00 m², if surrounded by plastic foil. The results presented in peas were compared to those in other crops and discussed concerning their relevance for variety testing as well as for selection of grain yield in early generations.     

新一代信息技术对农产品追溯系统智能化影响的综述

从为应对疯牛病问题至今,追溯系统作为农产品及食品质量安全保障的有效手段引入已有近30a,如何降低追溯断链化、增强追溯可信度、提升质量预警力,已成为追溯系统研究的热点,也是应用中亟待解决的问题。该文基于国内外相关文献,瞄准热点问题,综述了新一代信息技术对农产品追溯系统智能化的影响。首先,提出了追溯系统从1.0到3.0的发展历程,总结了追溯系统1.0以信息记录为主、2.0以数据整合为主、3.0以智能决策为主的核心特征;其次,描述了以物联网、大数据、云计算、人工智能、区块链等为核心的新一代信息技术之间在信息感知、数据处理、高效计算、智能分析、加密防伪等方面各有侧重又相互关联的内在关系,分析了大数据、人工智能及区块链的发展趋势;最后,从人工智能技术降低追溯过程断链程度、大数据技术提升质量安全预警能力、区块链技术增强全程追溯可信度等3个方面,综述了相关研究,结合发展趋势提出了深入研究的方向,即人工智能从供应链内部及供应链之间提升追溯粒度,大数据从微观、中观及宏观层面实现预测与优化,区块链从追溯区块结构优化、隐私保护及共识算法等方面增强追溯可信度。该文为把握农产品追溯系统发展趋势、研究热点、应用瓶颈提供有益参考。     

生态清洁小流域建设背景下农民环境风险意识与避险行为研究——以陕西省关中地区小湋河小流域垃圾焚烧发电项目为例

[目的]在生态清洁小流域建设背景下,探讨农民的环境风险意识与环境避险行为的相关性,为乡村振兴战略的顺利实施提供科学依据。[方法]以关中地区渭河三级支流小湋河小流域的垃圾焚烧发电项目为例,通过理论分析和到附近村落进行实地问卷调查,探讨在该项目建设论证中农民的环境风险意识和避险行为之间的逻辑关系是否还存在更深层的原因,或具有更复杂化的形态。[结果]结合调查资料与统计分析,发现小湋河小流域农民的环境风险认知过程呈现环境风险感知→环境风险意识→环境避险行为的演进样态。在此基础上构建环境风险意识与行为关系的理论模型。研究小流域农民环境风险意识和避险行为之间存在4组关系:有意识有行为、有意识无行为、无意识有行为、无意识无行为。[结论]意识与行为关系的理论模型在本研究实践检验中成立,农民的4类环境风险意识与相应的避险行为之间具有相关性。     

可持续发展目标下农作物秸秆收集运输的碳减排优化分析

在可持续发展目标下,加强农作物秸秆的回收利用是解决农村地区资源浪费和环境污染问题的重要途径。该研究以在方形区域收集秸秆的生物质电厂收集运输系统为研究对象,着重从碳减排视角构建秸秆收集运输模型,优化求解运输排放外部成本最小的收储点个数与回收距离。通过与不同收集系统的对比分析,综合评价所建系统在经济、环境、效率方面的优势以及与可持续发展目标的联系,提出推动秸秆资源低碳回收和高效利用的政策建议。基于河北省统计数据的研究结果显示：河北省秸秆资源丰富,绝大部分地区已具备良好的收集条件,仅廊坊、沧州、唐山的资源供需匹配度较低;所建系统在电厂外围安置12个收储点,没有收集盲区,避免了资源浪费,收集效率提高18.75%,碳排放外部成本减少83.98%,环境问题得到有效控制;此外,该系统还为环境保护、减少贫困、公共卫生和资源利用相关的10个可持续发展目标提供了多维度支撑。该研究设计的高效收集运输系统,提供了生物质能开发的低碳路径,对进一步构建农村生物质循环供能的闭环供应链一体化系统工程、推动农村地区的农业现代化和可持续能源发展,具有十分重要的理论和现实意义。     

降雨条件下灌草配置方式对褐土坡面径流泥沙特征的影响

为探究不同灌草配置方式对褐土坡面土壤侵蚀的影响,通过室内模拟降雨试验,以种植灌木胡枝子(Lespedeza bicolor Turcz.)以及草本紫花苜蓿(Medicago sativa L.)的褐土坡面为研究对象,设计3种降雨强度(30,60,90 mm/h)、3种灌草覆盖度(灌草覆盖度比例分别为1∶2(Ⅰ),2∶1(Ⅱ),1∶1(Ⅲ))以及3种灌草空间配置方式(灌木位于坡上(US)、坡中(MS)、坡下(LS)),分析降雨条件下不同灌草覆盖度及不同灌草空间配置交互作用下产流产沙及减流减沙特征。结果表明：(1)坡面产流产沙量在降雨初期大幅度增加,随后增加趋势逐渐减缓,最后趋于稳定。当灌丛位于坡下(LS)且灌草覆盖度为Ⅱ时,产流产沙量显著低于其他灌草配置方式。(2)不同灌草覆盖度减流减沙率大小关系为Ⅱ>Ⅰ>Ⅲ;不同灌草空间配置下减流减沙率大小关系为LS>MS>US。其中最大减流率达61.58%,最大减沙率达93.27%。不同灌草配置方式间的减流率及减沙率具有显著差异。(3)通过双因素方差分析研究灌草空间配置方式对坡面总产流产沙量的显著性和贡献率发现,灌草覆盖度和灌...     

复杂天气状况下的太阳能混合跟踪系统及控制判据

为了解决传统太阳能混合跟踪控制判据范围宽泛,不能准确识别天气情况的问题,该研究设计了一种复杂天气状况下的太阳能混合跟踪系统。通过分析非聚光与聚光条件下系统运行在不同跟踪策略下的跟踪特性,结合天气特征,提出以辐照度识别天气状况的多阈值控制判据。控制判据将天气划分为辐照度波动天气、高辐照度天气、低辐照度天气与辐照度极低天气,装置可根据外界气象变化自动调整光电跟踪、视日运动轨迹跟踪或固定倾角控制模式。该系统搭建Node-Red总控平台,采用并行控制,优化混合跟踪策略,控制信号稳定输出。试验结果表明：应用该判据的混合跟踪系统工作性能优良,非聚光条件下系统平均发电功率分别高出光电跟踪与视日运动轨迹跟踪0.03和0.16 W,聚光条件下系统平均发电功率达到0.81 W,高出光电跟踪0.03 W,高出视日运动轨迹跟踪0.55 W,由此可知,该系统能够提升光伏发电的输出电能,为太阳能混合跟踪系统的跟踪方式切换提供了理论依据。     

Adjustment for Competition Between Genotypes in Single-Row-Plot Trials of Winter Wheat (Triticum aestivum)

Several statistical methods were investigated for improving yield estimation for 72 genotypes of winter wheat tested in a single-row-plot (SRP) trial. The different analytical models were compared using several criteria: the residual mean square fit; the standard error of differences of genotype means; the correlations of genotype means with means from six-row-plot (6RP) reference trial; the expected genetic gains relative to 6RP trial from selecting the 10 top yielding genotypes. There was no significant correlation between the unadjusted genotype means for SRP and 6RP. Genotype yields were positively correlated with height in SRP, but this correlation was reversed in 6RP. Using the mean height difference of a plot with its two neighbours as a covariate to adjust for competition in SRP reduced the standard error of difference of genotype means and substantially increased their correlation with the 6RP means. The predicted selection efficiency in SRP trial increased from zero, before adjustment, to 83 % of 6RP trial. Including the difference in heading date and the effect of guards at borders as covariates in the SRP analysis improved the residual mean square fit but had no effect on correlation with 6RP means or selection efficiency. A producer-competitor model in which individual competitor effects were estimated for each genotype gave a substantial improvement in fit over the covariate models but a much lower correlation with 6RP means and selection efficiency. Yield selection in early generation wheat trials based on single-row plots could be considerably strengthened by use of a plot covariate derived from height difference between neighbours.     

换热设备螺旋和直细通道内扇形凹穴对流体流动和传热的影响

为探究结构表面(如凹穴)对换热设备螺旋和直细通道内流体流动和传热影响的差异,在这2种通道的两侧面加入扇形凹穴,并采用数值方法研究其在不同雷诺数下流动、传热、熵产以及综合性能的影响。结果表明:凹穴对螺旋细通道内流体的流动影响明显,摩阻系数最大提高23%,而对传热和综合性能几乎没有影响;低雷诺数时凹穴对直细通道内流体的流动、传热和综合性能的影响不明显,而高雷诺数时影响显著,摩阻系数和努塞尔数最大分别提高50%和45%,最大传热强化因子达1.27;凹穴可减少螺旋和直细通道内流体流动和传热过程的熵产,但在高雷诺数时才比较明显地减少,且对直细通道的影响大于螺旋细通道,熵产增大数的最小值分别为0.34和0.73。研究结果可为微细通道换热设备的性能改善提供参考。