In situ comparisons of ammonia volatilization from N fertilizers in Chinese loess soils

Ammonia volatilization loss from mineral N fertilizers was determined on a calcareous Chinese loess soil with a pH (CaCl₂) of 7.7. An original in situ method that required no electricity or laboratory analyses was used. By means of a bellows pump, ambient air was drawn through four conical cups placed onto the soil (total area 400 cm²) and subsequently through an NH₃-specific detector tube with direct colorimetric indication of the ammonia concentration (measuring range, 0.05–700 vol.-ppm NH₃). Duration of measurement was about 3 min. Following N fertilization to winter wheat in 1990 and to summer maize in 1991, the application methods surface broadcast, uniform incorporation into the 0–15-cm layer, and for maize, a point placement at 10 cm depth were investigated. Ammonium bicarbonate and urea were applied at rates of 100 and 200 kg N ha^–1. In the autumn of 1990, ammonia losses following NH₄HCO₃ application were more than twice as large as with urea, fertilizer incorporation reduced NH₃ losses 15-fold, and doubling the nitrogen application rate resulted in a 1.7-fold increase in the percentage of nitrogen loss. Cumulative ammonia fluxes were about 2 times higher in the summer of 1991. Comparing application methods in summer, losses were significantly (3 times) lower only with point placement. The above differences were all significant at the P<0.05 level. Due to the very low air exchange rate (0.9 volumes min^–1), actual volatilization rates were underestimated by this method. Though not yielding absolute amounts, the Dräger-Tube method proved very suitable for comparing relative differences in ammonia fluxes. The measurements clearly reflected the characteristic flux patterns for the different treatments and the effects of environmental factors on their time course.     

基于WSN的智能火灾报警系统研究

针对目前火灾报警系统存在的不足,提出了一种基于无线传感器网络的智能火灾报警系统。该系统以无线传感器网络节点为监测设备,完成火灾数据的采集及无线传输。利用RBF神经网络建立火灾探测器模型,对多元火灾数据进行融合,能够准确区分明火、阴燃火和非火灾源,达到了降低误报率的目的。     

Two Triacylglycerol Lipases Are Negative Regulators of Chilling Stress Tolerance in Arabidopsis

Cold stress is one of the abiotic stress conditions that severely limit plant growth and development and productivity. Triacylglycerol lipases are important metabolic enzymes for the catabolism of triacylglycerols and, therefore, play important roles in cellular activities including seed germination and early seedling establishment. However, whether they play a role in cold stress responses remains unknown. In this study, we characterized two Arabidopsis triacylglycerol lipases, MPL1 and LIP1 and defined their role in cold stress. The expression of MPL1 and LIP1 is reduced by cold stress, suggesting that they may be negative factors related to cold stress. Indeed, we found that loss-of-function of MPL1 and LIP1 resulted in increased cold tolerance and that the mpl1lip1 double mutant displayed an additive effect on cold tolerance. We performed RNA-seq analysis to reveal the global effect of the mpl1 and lip1 mutations on gene expression under cold stress. The mpl1 mutation had a small effect on gene expression under both under control and cold stress conditions whereas the lip1 mutation caused a much stronger effect on gene expression under control and cold stress conditions. The mpl1lip1 double mutant had a moderate effect on gene expression under control and cold stress conditions. Together, our results indicate that MPL1 and LIP1 triacylglycerol lipases are negative regulators of cold tolerance without any side effects on growth in Arabidopsis and that they might be ideal candidates for breeding cold-tolerant crops through genome editing technology.     

基于假设检验匹配约束的点云配准算法研究

针对点云配准中效率低、误差大、抗噪性弱等问题,提出了一种改进的基于t检验的迭代最近点(T-ICP)算法。在初始配准阶段,采用统计分析对源点云和目标点云中的离群点进行标记并提取非离群点,然后采用主成分分析法(PCA)计算非离群源点云和非离群目标点云之间的变换矩阵,并将变换矩阵应用于源点云。在精配准阶段,以迭代最近点(ICP)算法作为基本框架,通过对候选点对的邻域距离分布进行t检验来剔除错误点对,并采用均匀分布策略来搜索点对,保证点云的完整形态配准。实验结果表明,相较于迭代最近点算法以及近两年一些改进的配准算法,该算法在效率和精度上分别提高了10%~50%和4%~40%,并具有较好的鲁棒性。     

汽车电器系统电路故障的解决方法论述

当前,我国国内的汽车电子技术处于不断的发展阶段期,在这个时期,汽车电气成为汽车的重要组成部分.汽车的性能是客户在选择汽车时的重要依据,基于此,汽车性能的高低其实对于汽车而言具有重要的作用.当前,我国很多的研究学者重视汽车的研究内容,尤其是随着科学技术的不断发展,现代汽车自动化发展与电器化应用,更是直接促进了汽车的智能化...     

Extraction of accurate stomach contours from X-ray images of barium-filled stomachs and its application to detect potential abnormalities

The extraction of an accurate stomach contour from radiograms for mass screening and the detection of potential abnormalities using the derived contour are described. The difficulty of the extraction is that the shape and the brightness of the stomach region in radiograms change considerably depending on individuals or input conditions. The proposed method first obtains an approximate region and then tracks an accurate stomach contour by a multiresolution edge detector. The edge detector searches for an obvious local maximum in the differentiated data in a small search area near the approximate region in order to determine a contour point. If the local maximum is not ascertained, the search area is expanded. In the event that the larger area fails to reveal a local maximum, a contour point is determined by using a reference direction derived from the approximate region. The detection of abnormalities from the stomach contour obtained by this method has been satisfactory.     

Safety of vegetables and the use of pesticides by farmers in China: Evidence from Zhejiang province

In China there are great challenges to ensure the safety of vegetables, as highly toxic pesticides, which are more than likely to cause high pesticide residues in vegetables [Zhang, Y., Ma, J., Kong, X., & Zhu, Y. (2004). Factors that affect farmers’ adoption of non-pollution and green pesticides: Empirical analysis based on data from 15 countries (cities) in Shanxi, Shaanxi and Shandong province. Chinese Rural Economy, 1, 41–49], are still used in the production of vegetables by vegetable farmers. Based on a survey of 507 vegetable farmers from Zhejiang Province, this study attempted to identify and control the vegetable farmers who were at risk of spraying highly toxic pesticides onto vegetables in China. We found that farmers who were older and less educated and unspecialized vegetable farmers were more likely to use highly toxic pesticides. Our statistical results also indicated that vegetable farmers who received less training and selected handlers as their marketing channel had a tendency to apply highly toxic pesticides, whereas cooperative members were less likely to use these pesticides. Finally, vegetable farmers who had a poor understanding of vegetable safety issues were more likely to use highly toxic pesticides. Policy implications to control the use of highly toxic pesticides and ensure the safety of vegetables in China are discussed.     

葡萄酒品尝过程中美感的形成机理

葡萄酒一般清亮、晶莹、透明、有光泽，具有令人愉悦的外观和回味无穷的内涵，因而葡萄酒具有美学特性。葡萄酒品尝过程中美感活动是一种逐渐深化的过程，美感的形成机理研究由于哲学辩证法的借入，诠释葡萄酒品尝过程中美感形成的机理。由葡萄酒品尝过程中主观、客观存在的美感追溯其美感内涵，以提升葡萄酒品尝者对葡萄酒的欣赏水准，倡导葡萄酒消费审美文化，引领葡萄酒时尚品味，旨在使葡萄酒品尝者通过葡萄酒品尝，怡神悦意、净化心灵、完善人格、激励斗志、升华境界。