面向冷链物流农产品品质感知的TTI动态校准方法

时间-温度指示器(TTI)是一种可以跟踪冷链物流温度历程的智能装置,可以指示相应的农产品品质。但现有的TTI匹配条件在一定程度上限制了TTI的应用范围,即使TTI满足了传统匹配条件的要求,但应用效果也会受到农产品采收品质波动的影响。通过使用反应动力学方程和等量线方法,在原有的匹配过程中引入了TTI的校准过程,并借此推导TTI匹配所需的基本条件,以及校准过程所需的参数。结果表明,TTI匹配性判断所需的基本条件仅为农产品品质与TTI的反应活化能相等,或两者等量线存在比例关系。在此前提下,利用公式推导或等量线的绘制过程,可以求得静态校准和动态校准时所需的相关参数,经过校准后的TTI即可与对应的食品完成匹配。校准过程的引入可以显著扩大TTI的适用范围。除此之外,动态校准模型还可以缩小处于变化中的TTI和农产品对应品质之间的差值,提高TTI指示货架期的精确性。最后,通过使用两种酶型TTI、两种不同激活条件的化学型TTI和玫瑰香葡萄进行验证实验,实验结果证明经过合理校正之后TTI的等量线普遍与玫瑰香葡萄的品质等量线更接近,对其指示效果精准。     

基于OFDM-MIMO移动通信模型的采摘机器人设计

为了提高果树采摘机器人的智能化和自动化水平,提高机器人的实时通信和在线控制能力,实现机器人作业过程的远程控制,在采摘机器人通信系统中引入了OFDM-MIMO模型,并将移动4G技术应用到了机器人的设计中,突破了机器人控制距离限制,实现了机器人的跨区域无线通信。机器人采用视觉传感器和4G网络采集并传输图像,图像数据可以在远程浏览器端实时显示,便于掌握机器人作业信息。当机器人碰撞传感器发出信号时,可以利用OFDM-MIMO信道模型进行图像的高效传输,并将视觉传感器采集的图像信息传送给远程控制端,在采摘出现失误时可以及时地调整机器人的状态,实现果实采摘的在线控制。同时,设计了机器人的实验样机,并对机器人的果实定位能力和通信能力进行了实验和仿真。实验和仿真结果表明:该种机器人可以有效地识别普通果实和套袋果实,并且通信实验测试和仿真测试的结果吻合,从而验证了结果的可靠性及OFDMMIMO模型在采摘机器人通信系统中的可行性。     

泵站虹吸式出水管虹吸形成过程气液两相流数值模拟

为分析虹吸式出水管虹吸形成过程中气液两相流动,基于各向同性假设,采用欧拉多相流模型与RNG k-ε湍流模型对一泵站虹吸式出水管虹吸过程中的气液两相流进行了数值模拟。结果表明:虹吸过程中,在虹吸管驼峰段和下降段易产生上、下气囊,对虹吸作用的完成有不利影响。来流流量是影响虹吸形成时间的主要因素,水力驱气阶段和水力挟气阶段可分别用不同的幂函数来表达时间与流量的关系。     

鸭梨不同施氮期肥料氮的平衡及其效应

以3年生初结果的鸭梨/杜梨为试材,用~(15)N示踪技术探讨了秋施、春施及夏施肥料氮在土壤-植物中的平衡及其效应。结果表明,肥料氮损失量与植株吸收量之比表现为夏施>秋施>春施;肥料氮利用率以春施最高,秋施次之,夏施最低。肥料氮在植株体内的分配基本上随生长中心的转移而转移,无果中、短枝有优先累积肥料氮的效应。以秋施肥料氮的分配与植株生长节奏最吻合,并能刺激生长势弱的植株吸收利用肥料氮。显示出秋施氮对植株的效应最好。     

沪池沟流域水平梯田建设研究

沪池沟流域水平梯田建设研究孙天星，郑合英（黄河水利学校水土保持专业科，开封市４７５００１）沪池沟流域位于河南省西部洛宁县境内，系黄河二级支流，属黄土丘陵沟壑区第三副区，流域面积２３．２９ｋｍ２。该流域１９８８年被列为黄河中游水上保持综合治理试点小流域...     

陡山灌区实时灌溉预报研究

介绍了参考作物腾发量和实际作物腾发量的实时预报及修正方法 ,结合陡山灌区实际资料 ,分别针对主要旱作物和水稻建立了实时灌溉预报模型 ,并对模型各参数进行了率定 ,特别针对参考作物腾发量预报模型中 A0 的确定进行了分析 ,给出了更合理的 A0 取值方法。基于可视化语言开发灌溉配水实时决策支持系统 ,该系统界面友好 ,操作简单 ,实用性强 ,利于推广。     

灌区灌溉需水量的随机模拟

提出了一个含有趋势分量、季节分量、随机分量的时间序列模型，并用来模拟灌区灌溉需水量。分析发现灌溉需水量的序列无趋势，季节分量可用显著谐波数为1的Fourier级数描述，而随机分量则可用一阶自回归模型表示。对模型残差的独立性和正态性的检验证实了模型的适用性。实例计算表明该模型用于模拟霍泉灌区小麦的灌溉需水量序列精度可靠，合理可行。     

Critical drainage and nitrate leaching losses from manures applied to freely draining soils in Great Britain

Abstract. Pig slurry was applied by open-slot injection to experimental plots on a sandy loam site at ADAS Gleadthorpe, Nottinghamshire. Volume and distribution of over-winter drainage were adjusted through the use of rainfall exclusion covers or irrigation. The resultant slurry N leaching over the range of drainage values tested (up to 300 mm) could be satisfactorily described by curve-fitting, using a quadratic or exponential function. Initial simulations of slurry N leaching using the manure nitrogen decision support system manner (v. 3.0) compared poorly with the experimental data, predicting both earlier and greater amounts of nitrate leaching. However, the lack of fit could be explained by consideration of the likely ammonia emissions following slurry injection, the actual volumetric soil moisture capacity at the experimental site and the likely time delay for the nitrification of slurry N following application. Good agreement between modelled and observed data was achieved when these factors were taken into account. The manner model was used to simulate nitrate leaching beyond the range of drainage treatments tested in the experiments and the anticipated sigmoidal relationship between nitrate leaching and drainage was observed. The model was then used to study the effects of manure application timing and the likely impact on nitrate leaching, across the range of rainfall conditions found in Great Britain. Simulations for a range of manure types were undertaken, with manures applied at rates up to the limit of permitted N loading on freely draining sandy loams. Rainfall inputs for these simulations were based on long-term average climatic data. Results are presented for two contrasting manure types, cattle slurry and poultry manure, both of which are subject to controls in Nitrate Vulnerable Zones (NVZs) in Great Britain.     

Effects of alternative tillage systems on soil quality and yield of spring cereals on silty clay loam and sandy loam soils in the cool, wet climate of central Norway

Tillage trials were established on a poorly drained silty loam overlying silty clay loam and on a freely drained sandy loam overlying medium sand, in 1988 and 1989, respectively. Autumn and spring ploughing and two ploughless systems were compared for 12–13 years, with three replications at each site. The ploughless treatments comprised deep versus shallow spring harrowing until 1999, and thereafter autumn plus spring harrowing versus spring harrowing only. In 6 years, treatments with and without fungal spraying of the cereal crops were included. In other years, fungicides were not used. Perennial weeds were controlled by herbicides as necessary, on nine occasions up until 2001. Average spring barley (Hordeum vulgare L.) and spring oat (Avena sativa L.) yields were similar with spring ploughing as with autumn ploughing at both sites. In treatments without ploughing, average yields on the silty loam over clay were 93% of those obtained with ploughing, and on the sandy loam over sand they were 81%. Smaller and non-significant yield differences were found between spring harrowing versus deep spring harrowing, and between autumn plus spring harrowing versus spring harrowing only. Fungal spraying increased yields markedly at both sites (25%), but there was no significant interaction between this treatment and tillage system. Oat was compared with barley in 2 years, with oat performing better under ploughless tillage. At both sites increases in penetrometer resistance occurred in the topsoil of unploughed treatments. These were considered particularly limiting on the sandy loam. On the silty loam there was an increase in surface horizon porosity in the absence of ploughing, which was associated with an increase in topsoil organic matter content. On this soil there was also a tendency toward lower penetrometer resistance at >30 cm depth on autumn plus spring harrowed soil than on ploughed soil, indicating that the plough pan may have diminished. This was supported by observations of greater earthworm activity on unploughed soil. Soil chemical analyses revealed that mineral N and plant-available P and K accumulated in the upper horizon under ploughless tillage. The percentage yields obtained in individual years with autumn as opposed to spring ploughing, were positively correlated with air temperature during 0–4 weeks after planting on the silty loam, and with precipitation during 0–12 weeks after planting on the sandy loam. In the case of yields obtained with spring harrowing only, relative to spring ploughing, positive correlations were found with 0–4 week temperature on both soil types, suggesting that low early season temperatures may limit yields under ploughless tillage.     

重组K88黏附素亚单位蛋白在大肠杆菌中的诱导表达

采用响应面分析方法,对肠毒素大肠杆菌(EnterotoxigenicEscherichiacoli)K88黏附素亚单位重组蛋白FaeG诱导表达的主要影响因素进行了优化研究。响应面分析结果表明:不同的诱导时机、IPTG浓度及诱导时间对目的蛋白表达量均有显著影响(P<0.01),三因素之间的交互作用对目的蛋白表达量也有极显著的影响(P<0.01)。通过进一步的模拟优化,得到了最佳诱导表达条件为培养BL21(K88ac)重组菌株2.5h后,加入IPTG至终浓度0.8mmol/L,37℃诱导培养5h。采用以上参数进行验证实验,得到目的蛋白在全菌蛋白中的表达含量为35.4%;与单次单因子法得到的最佳表达条件下的表达量(27.5%)相比,提高了28.7%。采用响应面分析法可以确定IPTG的诱导时机、诱导浓度及诱导时间等多个因素对重组蛋白在大肠杆菌中表达的最佳作用条件,有利于提高目的蛋白的表达量。