对我国便携式林业机械参与国际标准化的思考

我国便携式林业机械发展迅速,但生产企业参与国际标准制定的很少,试验设施严重短缺,自主产品份额低.发达国家便携式林业机械标准化的现状与发展是从专利和标准层面主控世界市场,将加工重心移向发展中国家,而把工作重心转向负责其国际标准的制定.文章提出了改善我国便携式林业机械国际标准化现状的建议.     

Evaluating passive integrated transponder tags for tracking movements of round gobies

Abstract –  The round goby ( Neogobius melanostomus Pallas) is an invasive species in North America and Europe. We evaluated the efficacy of passive integrated transponder (PIT) tags for marking round gobies and tracking their movements with a portable underwater antenna in shallow areas (≤1 m) of a lake. Tagging did not markedly decrease growth of fish <105 mm; however, growth decreased unexpectedly for tagged fish ≥105 mm during the final sampling period. Nevertheless, tagging did not increase mortality regardless of size class, and tag retention was 100% for caged fish. Tagged round gobies in a 20 × 20-m² block net avoided detection by the portable underwater antenna, and a high proportion of fish probably escaped from the net, suggesting that round gobies may be more mobile than previously reported. In conclusion, PIT tags are a viable method for individually marking round gobies, but detecting tagged round gobies with a portable underwater antenna, given current technology, does not appear promising in shallow areas with low habitat complexity.     

Direct electrochemical flow analysis system for simultaneous monitoring of total ammonia and nitrite in seawater

The design and the performance of a new portable flow analysis (FA) system for the continuous, fast and accurate measurement of total ammonia and nitrite content in non-filtered seawater samples is demonstrated. The complete system has been optimized to operate within the ammonia and nitrite concentration range of 0.05–10 ppm. The system offers good reproducibility (<5%) and stability (<0.02 ppm/h) at constant temperature, while the analysis time is in the order of 1.5–4 min depending on the sample analyzed. The analysis results of seawater samples obtained with the FA system were compared to that obtained with the standard colorimetric method and establish the suitability of the analyzer for the precise and continuous measurements of untreated samples for both in field and laboratory applications. In addition, its small size and weight offer the advantage of portability, while its datalogging capabilities also allow for independent ammonia and nitrite monitoring.     

以PDA为终端的便携式农产品智能配送系统

农产品配送是整个农产品供应链的重要环节,快速获取和精准管理农产品装货、运输、卸货过程中的信息及实现配送过程的有效监控是保证农产品物流配送过程中质量安全的重要措施。该文设计了便携式农产品配送系统的框架、功能及数据库,并根据系统数据的更新频率设计了不同的数据更新机制;在此基础上,着重探讨了基于RDA的数据同步开发和条码扫描装卸货实现流程;系统采用VS.NET开发平台在模拟器上实现了功能。由于便携式农产品配送系统运行需要GPS、GPRS/GSM、条码扫描等模块的支持,因此根据各模块的不同组合,制定3种系统运行测试载体方案,通过综合比较,PDA内置GPS和条码扫描模块、通过蓝牙接口连接GPS模块的方案在目前情况下比较适合农产品配送企业使用。     

便携式番茄多品质参数可见/近红外检测装置研发

该文针对番茄独特的囊室结构及整体成熟度不均等问题,基于可见/近红外全透射光谱,研发了便携式番茄内外品质快速无损实时检测装置.该装置的硬件系统主要包括光源模块、信号采集模块、信号处理模块、电源模块、散热模块和打印模块,基于该硬件系统,采集了番茄630~1100 nm范围内可见/近红外透射光谱,选取650~1100 nm范围的光谱进行SG卷积平滑(savitzky-Golay smooth,SG-smooth)、标准正态变量变换(standard normal variable transformation,SNV)和多元散射校正(muliplication scattering correction,MSC)等预处理,建立了番茄颜色、硬度、总酸、总糖含量的偏最小二乘预测模型.基于QT开发框架编写了番茄多品质无损检测实时分析控制软件,植入番茄多品质参数预测模型,实现了番茄多品质参数检测一键式操作.为了测试该装置的检测精度和稳定性,选取与建模无关的20个同品种样品对每个样品的内外品质重复检测8次,结果表明:番茄颜色预测值与实测值相关系数为0.9528,均方根误差为2.7038,硬度预测值与实测值相关系数为0.9405,均方根误差为0.4486 kg/cm2,总酸含量的预测值与实测值相关系数为0.9537,均方根误差为0.3263%,总糖含量预测值与实测值相关系数为0.9610,均方根误差为0.1974%.番茄样品颜色、硬度、总酸和总糖重复检测最大相对误差分别为2.9%、1.9%、2.0%和1.6%.该便携式检测装置基于可见近红外全透射光谱,实现了番茄颜色、硬度、总酸、总糖含量的同时快速无损实时检测,预测精度及稳定性较好,可以满足实时评价番茄品质的市场需求.     

Investigation of intra-day variability of gaseous measurements in sheep using portable accumulation chambers

Portable accumulation chambers (PAC) enable short-term spot measurements of gaseous emissions including methane (CH₄), carbon dioxide (CO₂), and oxygen (O₂) consumption from small ruminants. To date the differences in morning and evening gaseous measurements in the PAC have not been investigated. The objectives of this study were to investigate: 1) the optimal measurement time in the PAC, 2) the appropriate method of accounting for the animal’s size when calculating the animal’s gaseous output, and 3) the intra-day variability of gaseous measurements. A total of 12 ewe lambs (c. 10 to 11 months of age) were randomly selected each day from a cohort of 48 animals over nine consecutive days. Methane emissions from the 12 lambs were measured in 12 PAC during two measurement runs daily, AM (8 to 10 h) and PM (14 to 16 h). Animals were removed from Perennial ryegrass silage for at least 1 h prior to measurements in the PAC and animals were assigned randomly to each of the 12 chambers. Methane (ppm) concentration, O₂ and CO₂ percentage were measured at 5 time points (T1 = 0.0 min, T2 = 12.5 min, T3 = 25.0 min, T4 = 37.5 min, and T5 = 50.0 min from entry of the first animal into the first chamber) using an Eagle 2 monitor. The correlation between time points T5-T1 (i.e., 50 min minus 0 min after entry of the animal to the chamber) and T4-T1 was 0.95, 0.92, and 0.77 for CH_4, O₂, and CO_2, respectively (P < 0.01). The correlation between CH₄ and CO₂ output and O₂ consumption, calculated with live-weight and with body volume was 0.99 (P < 0.001). The correlation between the PAC measurement recorded on the same animal in the AM and PM measurement runs was 0.73. Factors associated with CH₄ production included: day and time of measurement, the live-weight of the animal and the hourly relative humidity. Results from this study suggest that the optimal time for measuring an animal’s gaseous output in the PAC is 50 min, that live-weight should be used in the calculation of gaseous output from an animal and that the measurement of an animal’s gaseous emissions in either the AM or PM does not impact on the ranking of animals when gaseous emissions are measured using the feeding and measurement protocol outlined in the present study.     

高精度便携式X射线荧光光谱仪在污染农田土壤重金属速测中的应用研究

针对便携式X射线荧光光谱(PXRF)法中的高精度便携式X射线荧光光谱(HDXRF)法进行检出限(Cd元素)、稳定性和土壤标准物质准确性的测试,同时对农田土壤中主要重金属元素Cu、Zn、Pb、Cd和类金属As进行快速测定,并将测定结果分别与原子吸收光谱(AAS)法、原子荧光光谱(AFS)法及电感耦合等离子体发射光谱(ICP-AES)法的测定结果建立线性回归方程,以期分析土壤粒径、水分、有机质及土壤类型对测定结果的影响。结果表明:HDXRF法测定土壤中重金属的稳定性高、准确度高、检测限低,对Cd元素的检测下限为0.27 mg·kg-1。颗粒粒径对土壤重金属浓度测定结果有一定影响,样品过100目筛时的测定结果较理想;土壤含水量对HDXRF法的测定结果影响较大,应保证测试土壤样品干燥;有机质对HDXRF法的测定结果存在影响,但可通过调整方程的常数进行校准。HDXRF法测定值更接近实验室ICP-AES法的测定结果,Cu、Zn、Pb和Cd的决定系数分别为0.997 5、0.996 7、0.961 4和0.995 4;HDXRF法与实验室AFS法测定As的决定系数最高可达0.979 8。相比于实验室测定方法,HDXRF法只需简单的前处理,如风干、研磨等,且HDXRF法测定范围宽,适用于土壤中重金属Cu、Zn、Pb、Cd和类金属As的快速测定,是一种简单、快速、准确、可靠的分析方法。     

便携式牛乳蛋白质含量检测仪设计与验证

为了给牛乳蛋白质含量检测提供一种操作简便、成本低廉的便携式仪器,基于595 nm下考马斯亮蓝G-250染料中的疏水基团在酸性条件下与蛋白质的疏水微区具有较强亲和力,从而影响光透射特性的原理,设计了一种便携式牛乳蛋白质含量检测仪。该检测仪的硬件主要由单片机、光源模块、光传感器模块、输入输出模块和电源模块等组成;软件由Keil C51编写,并由主函数、光照度采集子函数、数据预处理子函数、显示子函数和蛋白质含量计算子函数等组成。以生鲜牛乳为对象,研究了透射光照度与蛋白质含量之间的关系,发现随着蛋白质含量的增加,透射光照度减小,二者具有良好的线性关系,其线性决定系数为0. 872。对比该仪器的蛋白质检测结果表明,同凯氏定氮法相比,本检测仪的绝对误差范围是±0. 08 g/(100 g),平均绝对误差为0. 05 g/(100 g)。此外,该检测仪的检测时间小于2 s,可快速、有效地检测牛乳中蛋白质含量。     

U形渠道便携式板柱结合型量水槽水力性能研究

针对灌区小型渠道数目多、需测控的断面多、而宜采用的移动式量水设备仍不够完善的问题,借鉴移动式薄板量水槽和圆柱量水槽的优点,设计了一种便携式板柱结合型量水槽,在分析量水槽测流机理的基础上,开展原型试验和数值模拟研究,并应用量纲分析法建立测流公式。结果表明,量水槽具有较好的水位-流量关系,上游壅水高度在1. 85～13. 69 cm之间,临界淹没度在0. 70～0. 91之间,槽前弗汝徳数均小于0. 5;板柱结合型量水槽比现有的圆柱量水槽和带尾翼的圆头量水槽体型小,便携度高,流线分布稍差,上游壅水高度稍大,临界淹没度稍低,但能满足灌区测流要求;量水槽测流精度高,平均测流相对误差为2. 07%。