电子鼻检测技术在粮食霉变识别中的应用研究

针对其在粮食霉变检测领域进行了研究,讨论了粮食霉变的生物化学过程、电子鼻的组成和工作原理。对电子鼻在粮食霉变识别中的研究进展进行了论述和评述,并就电子鼻的发展方向和应用前景进行了探讨。     

远程智能化环境参数监控系统硬件设计

应用电子技术、传感器技术、Internet技术、嵌入式技术、自动控制技术实现对被监控区域环境参数的智能化监控与自动控制。设计的智能化环境监控系统可以对多个环境因子同时进行检测、预警和自动控制并能通过互联网进行远程通讯,适用于温室、家居、办公环境、大型商业区等多种场所。     

Effects of harvest time and low temperature storage on the texture of cabbage leaves

Leaf textures of four cabbage cultivars (T-520, Fuyu-nobori, Satsuki-ou, and Kinkei-201) harvested in winter and spring were evaluated. Acoustic vibration signals generated during penetration of four stacked cabbage leaves were measured using a novel texture measurement system. Texture was quantified using a texture index (TI). The TI of T-520 was higher than that of Fuyu-nobori and continually declined during the entire investigation period (between February and May). However, Fuyu-nobori's TI persisted after early April. This implied that Fuyu-nobori was superior to T-520 in terms of preservation of quality. Satsuki-ou showed either an equivalent or higher TI than T-520 in May. Kinkei-201 had a much lower TI than the other cultivars. TIs of T-520 and Fuyu-nobori stored at a 5 °C for 4 weeks were lower than those of samples without storage. This implied that low temperature storage did not effectively retain the texture quality of the cabbages.     

基于无线传感器网络的农田自动节水灌溉系统

提出了一种基于无线传感器网络的农田自动节水灌溉的构建方案,详细介绍了传感器节点和灌溉控制器的设计。无线传感器网络实时采集、传输传感器数据,灌溉控制器控制灌溉管网,分区域实时灌溉并调节土壤湿度,实现精细农业所要求的时空差异性和水资源高效利用。     

早期香蕉枯萎病Foc4双探针核酸纸基检测传感器研制

为实现对早期香蕉枯萎病4号生理小种(fusarium oxysporum f.sp.cubense 4, Foc4)的准确检测,该研究提出一种基于胶体金的双探针纸基传感器。该传感器将2种不同粒径的胶体金分别与检测探针和信号增强探针结合,利用DNA探针代替抗原和抗体,形成双探针体系,通过增加信号增强探针降低检测限。基于目标序列与双探针体系的碱基互补配对形成“金标探针-目标序列-T线探针”复合物并在传感器的测试区被捕获,10 min内形成肉眼可见的目标产物,通过分析测试条带得到光强度峰面积并代入标准曲线中,实现Foc4定量检测。试验结果表明,双探针纸基传感器的检测限达到0.001 nmol/L,是传统纸基传感器的100倍,提高了检测灵敏度;在0.001～1000 nmol/L范围内,Foc4浓度与测试线光强度峰面积呈线性关系;使用高浓度非互补探针进行试验干扰,发现非互补序列对检测效果基本无影响,表明该传感器具有较好的特异性;香蕉叶片Foc4检测的平均回收率为77.6%～102.3%,相对标准偏差为7.4%～7.7%。与传统形态学观察等检测方法相比,该研究提出的双探针核酸纸基检测传感器可以及时、快速、准确地判断早期Foc4的存在,具有良好的推广性和实际应用价值。     

料浆隔膜泵隔膜破裂预报警与事故报警电路设计

采用PLC为控制核心,实现了对料浆隔膜泵主要部件——隔膜的破裂进行预报警与事故报警的电路设计。设计完善了料浆隔膜泵的整体控制系统,提高了料浆隔膜泵的实际工作能力。     

精准灌溉系统无线传感器网络休眠技术研

结合精细农业应用需求,对传感器网络中常用的节点供电方式及其特点进行了分析.为延长普通干电池供电的节点寿命,基于节点能耗分析,提出了应用层主导的节点休眠/同步机制,并提供了根据节点期望寿命与数据采集需求计算空占比的方法.最终在实际传感器网络节点上实现了休眠/同步机制,并在国家农业信息化工程技术研究中心的小汤山农业基地进行大量实验,无休眠设计寿命约150h的节点采用休眠技术后节点寿命可达到1年以上.     

Remotely sensed spawning habitat of Pacific sardine (Sardinops sagax) and Northern anchovy (Engraulis mordax) within the California Current

We use trivariate kernel density estimation to define spawning habitat of northern anchovy ( Engraulis mordax ) and Pacific sardine ( Sardinops sagax ) in the California Current using satellite data and in situ egg samples from the Continuous Underway Fish Egg Sampler (CUFES) deployed during surveys in April by the California Cooperative Oceanic Fisheries Investigations (CalCOFI). Observed egg distributions were compared with monthly composite satellite sea surface temperature (SST) and surface chlorophyll a (chl a ) data. Based on the preferred spawning habitat, as defined in SST and chl a space, the satellite data were used to predict potential spawning habitat along two areas of the west coast of North America. Data from the southern area (21.5 to 39°N) were compared to observations from the CUFES data for the period 1998–2005. Northern anchovy and Pacific sardine exhibited distinctly different spawning habitat distributions. A significant relationship was found between satellite-based spawning area and that measured during surveys for sardine. CUFES area estimated for sardine was similar in magnitude to that estimated from satellite data (∼60 000 km²). In contrast, spawning habitat of anchovy averaged between 1000 and 200 000 km² for the period 1998–2005, for CUFES and satellite estimates, respectively. Interannual variability in the area (km²) and duration (months) of estimates of suitable habitat varied between species and between the northern (39 to 50.5°N) and southern portions of the California Current. Long-term monitoring of habitat variability using remote sensing data is possible in the southern portion of the California Current, and could be improved upon in the northern area with the addition of surveys better timed to describe relationships between observed and estimated spawning habitats.     

基于小波奇异点和能量分布的传感器突发故障诊断

提出了运用小波变换分析传感器输出信号,检测和诊断传感器自身突变类型故障的方法。推导了运用传感器正常输出信号和5种典型突变性故障信号的小波变换,通过检测信号小波变换的奇异点,确定传感器突变型故障突变位置,从传感器典型故障信号在各小波尺度下分解时能量分布的不同,得到和故障类型相关性密切的特征向量矩阵,作为判断故障类型的根据。计算机仿真模拟硅压力传感器所获得的结果证实了方法的有效性。     

Development of the Berry Impact Recording Device sensing system: Hardware design and calibration

Bruising caused by the impact damage occurs frequently during mechanical harvest process for highbush blueberries. The overall goal of this study was to develop a miniature and low-cost sensor prototype to quantitatively measure the impact forces endured by blueberries during the mechanical harvest process, which could be used to reduce blueberry bruising through improved harvester design. The sensing system developed in this study had three essential components: the sensor, the interface box, and the computer software program. The round circuit board of sensor is less than one inch (19.4 mm), including three accelerometers with ±500 g sensing range in each orthogonal axis, one eight-bit microcontroller, one 128 KB memory chip, and other electronic components with low power consumption. The sensor board and rechargeable battery were cast into a one inch (25.4 mm) sphere using silicone rubber. The interface box serves as the intermediate communication platform to connect the sensor and the computer. The PC-software retrieves data from the sensor via the I²C communication and downloads data to a computer for further analysis via the RS232 communication. The sensor was calibrated using a centrifuge. The accuracy of the sensor output was 0.53% (2.60 g maximum deviation) and −0.33% (−1.26 g maximum deviation), with precision error of 0.63% (3.21 g) in the output span. This miniature and low-cost sensor prototype provides the opportunity to understand how the berry (or other small fruits) interacts with different machine parts within the harvester and to identify critical control points that cause the most mechanical impacts, which was not achievable in the past.