储粮压力对玉米粮堆温度场影响的实验与模拟研究

粮堆温度场的分布受储粮压力变化的影响较大。利用自制粮堆实验装置进行了三种不同储粮压力下玉米粮堆静态储藏实验。通过在两壁面提供恒定的温度梯度,竖向方向施加不同压力构建出粮仓内多因子实验环境。根据测点数据拟合出了不同时刻温度分布云图,以及不同储粮压力下温度场变化趋势,得出储粮压力对玉米粮堆温度场的影响规律。并采用COMSOL软件对不同工况下温度场的分布进行数值模拟,模拟结果验证了随着储粮压力增大,粮堆内热量传递也变缓慢,达到稳态时的温度也越低。     

气象站、粮仓和粮堆的温湿度相关性分析

为提供精准的粮食仓储气象服务,保障粮食仓储安全,基于2017—2020年佳木斯地区三个粮库和当地气象台站的观测资料,利用数理统计方法,探索分析了台站和粮仓内外的温度、相对湿度及其相关性.结果表明:气象台站实时温度大多低于粮库仓外温度,二者呈同步震荡变化,差异较小,R在0.996以上,气象台站相对湿度高于粮库仓外相对湿度...     

米糠油对小麦中玉米象的防治效果研究

通过米糠油对玉米象生物效应的实验室测定表明米糠油在不拌粮条件下，对玉米象有明显的引诱作用，引诱虫量与米糠油用量成正相关，在拌小麦条件下，对玉米象有明显的驱避作用，驱避率随米糠油用量的增加而上升，用量达１１．８ｍｌ／ｋｇ时，驱避率为９４．４％，当用量≥４ｍｌ／ｋｇ的米糠油拌粮时，对玉米象成虫有致死作用，用１６ｍｌ／ｋｇ拌粮时３－１０天后成虫死亡率达到了７１．８－８５％；米糠油能抑制玉米象的繁殖，降低     

粮食储藏中粮堆温度与大气温度之关系

本文着重阐述了已通过国家科技部验收的国家“九五”重点科技攻关计划项目-智能化粮情检测分析控制系统专题（96-615-05-02）实施过程中,使用统计软件SAS对辽宁沈阳,丹东,广西梧州,河南漯河等粮库的粮情检测数据进行分析的方法及结果。通过对粮堆温度与大气温度资料进行的相关分析。结果表明粮堆温度与大气温度间存在着明显的相关关系。但这种相关关系并非是纯线性的,而是随着测温点位置的不同,粮堆温度的变化表现出相对大气温度变化的滞后,这一相关系数随着测温点位置与外界距离的加大而呈现出递减趋势。     

小麦粮堆中玉米象和黄曲霉发生与二氧化碳浓度变化关系研究

明确害虫和霉菌发生与粮堆CO2浓度变化的关系,可为通过粮堆CO2浓度变化来监测虫霉发生奠定基础,有利于粮食储藏安全。本文构建了四种不同模拟粮堆(模拟自然带菌粮堆、模拟害虫发生粮堆、模拟霉菌发生粮堆、模拟虫霉发生粮堆),具体研究了25℃下水分12.5%和15%小麦四种模拟粮堆CO2浓度变化情况。结果显示,水分12.5%小麦模拟自然带菌粮堆CO2浓度30天内未出现显著变化(P＞0.05),模拟玉米象发生(50头/kg)粮堆第2天CO2浓度即达0.5%以上,第15-17天后快速增长,并于第23天达到4.5%,粮堆处于虫霉共同发生状态;模拟黄曲霉发生粮堆在第15天前CO2浓度变化不显著,至第30天时CO2浓度也未超过0.04%;玉米象与黄曲霉共同发生粮堆第2天CO2浓度即达到0.6%以上,第13-17天出现快速增长期,并于第26天达到4.5%以上,粮堆虫霉共同发生状态明显。水分15%小麦四种不同模拟粮堆CO2浓度变化与水分12.5%小麦粮堆基本一致,霉菌开始生长繁殖,黄曲霉发生粮堆、玉米象和黄曲霉共同发生粮堆的CO2浓度增加更快、幅度更大。分别对四种模拟粮堆CO2浓度变化进行模型拟合,各拟合模型均具有较高的精度。研究结果初步明确了害虫和霉菌发生时粮堆CO2浓度变化的关系,为利用粮堆CO2浓度变化来监测粮堆粮情变化提供参考。     

广东地区浅圆仓玉米粮堆温度分布规律研究

为了解浅圆仓玉米储藏全年的粮堆温度变化规律,采用实仓调查的方法分析了广东地区一浅圆仓玉米入仓后第一年粮温在垂直方向和水平剖面上的变化,并通过温差和露点评估了粮堆表层的结露风险。结果表明：在垂直方向上,粮面下5 m范围内粮食受夏秋季太阳热辐射影响,温度超过20℃的时间在2个月以上,空调控温工艺能将仓温和表层粮温有效降低至25℃及以下,但在秋季空调关闭后,粮面下9 m范围的粮温有不同程度反弹升高;在水平剖面上,内外圈温差明显,温差大小受粮层深度和季节影响,同时受仓体周围遮挡物影响,阳光直射多的方向粮温高于其他方向;粮堆表层内圈范围在空调控温前结露风险较高。     

粮堆密封的方法及应用

着重介绍了粮堆薄膜密封的几种做法、气密要求和应用实例。粮堆薄膜密封的方法有一面封、五面封、六面封等。在实际运用中,粮堆薄膜密封可以进行低温储粮、膜下环流熏蒸、膜下环流均温、不揭膜通风、气囊密闭充氮气调。但在运用时应注意塑料薄膜的选择、薄膜的分块、槽管的预埋和裁制;要及时揭膜,严防结露,同时要预留扦样孔方便粮情检查。     

储粮粮堆温度传导的距离-时间-温度曲线模型研究

基于热传导基本理论和粮仓温度监测要求,提出了距离-时间-温度曲线的概念,并给出了距离-时间-温度曲线的获得方法。由距离-时间-温度曲线可以估算出粮仓温度监测器的设置距离和温度检测的时间间隔,所得结果与解析解相比,相对误差小于1.0%。     

粮堆温度预测插值算法的研究

温度变化对粮堆内的微生物滋长和虫害活动有着十分重要的影响,对粮堆温度进行准确监测和预测是保障储粮品质和安全的关键因素.本文通过对实际粮堆温度传感器节点阵列的历史数据进行挖掘分析,提出了基于时间-空间相结合的粮温预测模型,可对各个节点未来时刻的温度值进行预测,并可通过此模型对未知节点温度进行预测插值,以得到未来时刻粮库的...     

Insect-corn kernel interaction: Chemical signaling of the grain and host recognition by Sitophilus zeamais

In living organisms, the cuticle has structural functions and is involved through chemical signaling in biological interactions such as plant-insect and provides protection against biotic and abiotic factors, thereby avoiding desiccation or the attack of predators. The objective of this study was to investigate the participation of the epicuticle in the maize kernel-Sitophilus zeamais interaction. The GC-MS analysis of the epicuticle extract demonstrated the presence of aliphatic hydrocarbons, alcohols, ethers, fatty acids, sterols and their derivatives. The results of bioassays show that the epicuticle of maize has a primordial role in its interaction with S. zeamais, and participates in the recognition and attraction to the food source, as well as regulating its reproduction. In addition the compounds present in the epicuticle extract may act as signal molecules and development regulators. This study reveals the effect of the maize kernel cuticle on Sitophilus behavior and contributes to the understanding of the interaction.     

利用啤酒糟制备高品质饲料蛋白

通过刀片粉碎和筛分技术对啤酒糟进行预处理,对筛下物进行球磨处理、固态酶解和有益微生物发酵,可以显著提高啤酒糟的饲用品质,制备高品质饲料蛋白。啤酒糟经刀片粉碎后过60目筛,筛下物粗蛋白含量达到38.8%,粗纤维含量降低到1.89%,实现蛋白-纤维的初步富集分离。对筛下物球磨后,经纤维素酶、木聚糖酶和蛋白酶混合固态酶解和产朊假丝酵母JX-09固态发酵之后,其粗蛋白含量达到45.17%,比啤酒糟原样提高了59.6%,多肽含量从0.68%提高到5.21%,蛋白体外消化率从53.7%提高到61.8%,水解氨基酸总量达到42.18%,比啤酒糟原样提高了60%,必需氨基酸总量达到17.3%,比啤酒糟原样提高了60%,粗纤维含量达到1.66%,比啤酒糟原样降低了89%。     

Deltamethrin- and spinosad-mediated survival,activity and avoidance of the grain weevils Sitophilus granarius and S. zeamais

The granary and maize weevils are serious worldwide threats to stored products and their control has heavily relied on synthetic insecticides, which are largely recommended based on studies with acute lethal doses neglecting the importance of potential sublethal effects of insecticides. Deltamethrin has been widely used for managing grain weevils and other stored grain pest species, but reported control failures with this insecticide sparked the search for alternative insecticidal compounds. The bioinsecticide spinosad is one of such alternatives whose use against stored grain insect pests is relatively recent, but encompasses the control of grain weevils. Nonetheless, little is known about the sublethal effects of spinosad on these insect pest species. Here we assessed the insecticidal effects of commercial formulations of spinosad and deltamethrin against the weevil species Sitophilus granarius and S. zeamais. Both spinosad and deltamethrin were able to effectively control the insects, although the latter caused a faster mortality than the former. Behavioral pattern changes were caused by both insecticides, especially deltamethrin, triggering irritability (i.e., avoidance after contact). Different feeding and drinking responses were also detected for both weevil species, which exhibited significant avoidance to deltamethrin and to spinosad, but with a milder response to the latter. Apparently spinosad is not as easily recognizable as deltamethrin by S. zeamais and S. granarius, remaining effective against both species without minimizing as much the potential exposure as deltamethrin.     

Chemical bases for maize grain resistance to infestation and damage by the maize weevil,Sitophilus zeamais Motschulsky

It was suggested that the factors that confer resistance on a maize variety against Sitophilus zeamais Motschulsky are chemically based. To test this hypothesis, resistance indices of the weevil were assessed using a new scale developed by Nwosu et al. (2015a) after performing detailed chemical analysis of the whole-maize grain using twenty elite maize varieties under ambient temperature and relative humidity of 30.7 °C and 74.5% respectively. Increases in maize varietal crude fibre, phenolic acid and trypsin inhibitor increased significantly mortality of S. zeamais adults and reduced significantly survival rate of S. zeamais adults, percent of grain damage, percent of weight loss, weight of grain flour and oviposition by the adult females. The level of cystein proteinase inhibitor (a natural protectant of plants against insect attack) in the grains was not on its own responsible for increased mortality, reduced grain damage and reduced oviposition. The study identified crude fibre, phenolic acid and trypsin inhibitor of whole-maize grain as the bases for resistance. Their significant increase in grains resulted in low infestation. Whereas, increased protein, zinc, magnesium, calcium, sodium, phosphorus, manganese, iron, cobalt and starch rendered the elite maize grains susceptible to S. zeamais attack. Therefore, significant incorporation of the bases for resistance and significant reduction of the bases for susceptibility in maize grains during breeding programmes is advocated; provided this does not adversely affect palatability and nutritional needs of man. Eighty-five percent of the elite maize varieties were at least resistant to S. zeamais infestation and damage. The resistant varieties, particularly 2000SYNEE-WSTR and TZBRELD3C5 maize with high resistance should be promoted for growing. Antibiosis, antixenosis and preference were the mechanisms of maize grain resistance to S. zeamais attack.     

粮仓内水分和温度变化的数值模拟分析

采用数值模拟的方法对粮仓内温度和水分随时间的变化进行研究。在数值模拟过程中,对真实粮仓进行一定的简化,建立了相似的物理模型,并与经典实验做对比,验证模型的可靠性。根据多孔介质的局部热质平衡原理和体积平均法,对不同初始温度的粮堆进行数值模拟分析,获得了粮食内部水分和温度随时间的变化规律。当温差从20℃增加到40℃时,粮仓内水分和温度变化也随之加剧。研究结果为预防粮食在储存过程中发生霉变、结露提供了科学依据。     

Spectrofluorimetric,spectrophotometric and chemometric analysis of wheat grains infested by Sitophilus granarius

Invisible infestation of wheat grains by Sitophilus granarius during postharvest handling is one of the main problems particularly for small enterprises and farm grain storage facilities due to the lack of cheap and fast methods for early detection of infestation, especially when only a small proportion of grain is infested by larvae. In order to determine whether the spectrofluorimetric, spectrophotometric or chemometric analysis of various extracts of wheat grains infested by S. granarius larvae could be used for detection of infested grain, four different types of extracts: 50 mmol dm⁻³ Tris–HCl pH 8.9, aqueous iso-propanol (φ = 0.55), methanol, and aqueous trichloroacetic acid (γ = 0.2 mg cm⁻³), of non-infested and infested wheat grains have been examined for fluorescence properties and UV/VIS spectral characteristics, while the chemometric analysis included determination of protein, reactive amino groups, polyphenols and soluble sugar content. Analysis of extracts revealed significant differences in UV/VIS spectral characteristics, level of reactive amino groups and polyphenol content between infested and non-infested grains. The results obtained indicate that instrumental analysis of spectral characteristics of grain extracts could be used as a method for determination of grain infestation.     

烟草内生细菌种群特征分析

采用研磨组织稀释分离法分离不同品种、不同器官、不同生长期的烟草内生细菌,以各菌群出现与否为指标,用类平均法对数据进行系统聚类分析,对内生细菌的种类组成,分布特征进行了研究。结果表明,烟草内生细菌种类分布存在品种差异、生长期差异和组织部位差异;优势菌群的组成随分离组织部位和生长时期的不同而变化。Bacillus sp.和Rhizobium sp.是四个品种烟草叶片共有的优势类群,从苗期到团棵期,内生细菌的种类在增加,B. pumilus广泛存在于成熟期烟草根、茎、叶中,且为主要菌群。部分内生细菌具有组织偏好性,Micrococcus sp.和Staphylococcus sp.对烟草的茎部具有偏好性,B. cereus对烟草叶片具有偏好性。对烟草这一重要经济作物内生细菌的种类组成、分布特征进行研究,可为科学认知和利用这类微生物资源奠定基础。      

Laboratory evaluation of traps for the detection of beetle pests in bulk grain

Traps have been evaluated against three species of storage beetle in plastic bins containing 150 kg wheat. The bins were used to generate data for a comparison of the trapping effectiveness of the pitfall cone (PC), pitfall beaker and insect probe traps. The data produced reflect those obtained from field studies and illustrate the advantages of this method over less rigorously controlled field trials. The PC trap, a single type developed to replace both of the previously recommended traps, buried to a 5 cm depth in grain, was as effective as the insect probe for detecting Cryptolestes ferrugineus. The buried PC trap was also as effective as the insect probe trap for trapping Oryzaephilus surinamensis below the grain surface, and the PC trap on the surface was as effective as the pitfall beaker trap. The PC trap below the surface was more effective for trapping Sitophilus granarius than the insect probe trap. This pilot-scale method is a cost-effective alternative to field-scale trials and could be used to investigate various factors influencing trap catch.