Trace Identification and Visualization of Multiple Benzimidazole Pesticide Residues on Toona sinensis Leaves Using Terahertz Imaging Combined with Deep Learning

Molecular spectroscopy has been widely used to identify pesticides. The main limitation of this approach is the difficulty of identifying pesticides with similar molecular structures. When these pesticide residues are in trace and mixed states in plants, it poses great challenges for practical identification. This study proposed a state-of-the-art method for the rapid identification of trace (10 mg·L⁻¹) and multiple similar benzimidazole pesticide residues on the surface of Toona sinensis leaves, mainly including benzoyl (BNL), carbendazim (BCM), thiabendazole (TBZ), and their mixtures. The new method combines high-throughput terahertz (THz) imaging technology with a deep learning framework. To further improve the model reliability beyond the THz fingerprint peaks (BNL: 0.70, 1.07, 2.20 THz; BCM: 1.16, 1.35, 2.32 THz; TBZ: 0.92, 1.24, 1.66, 1.95, 2.58 THz), we extracted the absorption spectra in frequencies of 0.2–2.2 THz from images as the input to the deep convolution neural network (DCNN). Compared with fuzzy Sammon clustering and four back-propagation neural network (BPNN) models (TrainCGB, TrainCGF, TrainCGP, and TrainRP), DCNN achieved the highest prediction accuracies of 100%, 94.51%, 96.26%, 94.64%, 98.81%, 94.90%, 96.17%, and 96.99% for the control check group, BNL, BCM, TBZ, BNL + BCM, BNL + TBZ, BCM + TBZ, and BNL + BCM + TBZ, respectively. Taking advantage of THz imaging and DCNN, the image visualization of pesticide distribution and residue types on leaves was realized simultaneously. The results demonstrated that THz imaging and deep learning can be potentially adopted for rapid-sensing detection of trace multi-residues on leaf surfaces, which is of great significance for agriculture and food safety.     

铬盐清洁生产中铬渣的综合利用

利用二氧化碳与液相氧化铬盐清洁生产工艺所产生的铬渣反应 ,得到碳酸氢镁溶液和富铁渣。碳酸氢镁溶液经加热分解得到轻质碳酸镁产品 ,富铁渣可以作为水泥行业原料铁精矿的替代品 ,最终实现了铬铁矿资源的充分利用和铬盐生产的零排放。     

传统法制备嗪草酮印迹聚合物

农药嗪草酮应用广泛,它的残留问题引起了人们的普遍关注,发展快速准确的检测方法势在必行。而分子印迹技术因其独特的优点使它成为痕量残留快速检测的一种较好的方法。采用传统法制备嗪草酮印迹聚合物,以甲基丙烯酸(MAA)为功能单体,N,N-亚甲基双丙烯酰胺为交联剂,甲苯为溶剂,在50℃时聚合得到选择性、吸附性最佳的印迹聚合物。     

An Attractive Synthetic Approach to Methyl Formate from Methanol via Methyl Nitrite

Catalytic synthesis of methyl formate has been investigated by a novel route starting from methyl nitrite in vapor phase. The acidic sites of the catalysts play a crucial role for the catalytic activity and the selectivity of formation of methyl formate. The H-Y zeolite catalyst gave higher yield and selectivity of the target product. This study provides a new approach for the synthesis of methyl formate from methanol via methyl nitrite.     

AlCl3/活性炭催化甲基三氯硅烷与低沸物再分配反应研究

甲基三氯硅烷(M1)与低沸物(LBR)是工业上"直接法"生产二甲基二氯硅烷单体过程中产生的副产物,两者之间通过再分配反应可转化为高价值的有机硅单体.以活性炭为载体,采用浸渍蒸发煅烧法制备了负载型AlCl3固体酸催化剂,在固定床反应器中进行甲基三氯硅烷与低沸物的再分配反应,制得二甲基二氯硅烷和三甲基氯硅烷.考察了活性炭载体预处理方式及反应条件对再分配反应的影响.结果表明,经过高温扩孔处理的活性炭载体负载的AlCl3催化剂具有较好的反应活性;优化的反应条件为:W(M1/LBR)为2.0～3.0,反应温度为310℃,LHSV为1.5 h-1;该催化剂的制备过程简单,催化反应条件温和且表现出良好的催化稳定性.     

出口柑桔中双甲脒及代谢物残留量测定

柑桔样品中双甲脒及代射物在酸性条件下回流水解成2，4－二甲基苯胺，正己烷提取，酸，碱反复液－液分配净化，七氟丁酸酐将2，4－二甲基苯胺衍生成2，4－二甲苯七氟丁酰胺，用配有电子俘获检测器的气相色谱仪测定，外标法定量。     

固相萃取技术在农药残留分析中的应用

固相萃取是一种新型的样品预处理技术，操作简便，节省有机溶剂，易于实现自动化操作，已广泛应用于环境保护、药物检测、食品检验检疫等领域。在农药残留分析中，固相萃取技术的应用还使得提取不同类别农药的选择性增强，样品回收率提高，尤其是结合HPLC—MS、GC-MS、CE-MS等仪器的联合鉴定，可实现自动化分析，能简单、快速、灵敏地提取定量许多物质，从而大大提高了分析效率和精密度，具有广阔的发展前景。     

超声波提取-吸附分离-气相色谱法测定茶叶中农药残留

将超声提取-吸附分离的预处理技术用于气相色谱法检测茶叶中的农药残留。对超声波提取条件和吸附分离柱（自制）的结构进行了优化。建立了茶叶中有机磷类和菊酯类农药残留的气相色谱法定量测定的方法。进行了3个质量分数的标准添加，甲胺磷、乐果、联苯菊酯、氯氟氰菊酯、溴氰菊酯的回收率相应为75％～95％、87％～110％、89％-102％、88％-105％、80％-93％，相对标准偏差为2．6％．4．8％，检出限为0．005-0．02mg／kg。该方法速度快、灵敏度高、重现性好。     

Agricultural use of three organic residues: effect on orange production and on properties of a soil of the ‘Comarca Costa de Huelva’ (SW Spain)

Disposal of urban, agricultural and industrial organic residues impliesan increasing problem because of all the economic and environmentalrepercussions involved. One of the most adequate ways of managing this problemis the agricultural use of these wastes as organic amendments. Three organicresidues (AC, olive mill waste water sludge compost; MWC, municipal solid wastecompost; and PS, paper mill sludge) were used in a 3-year field experimentinvolving orange production. The effect of their application on crop productionand on soil quality was investigated. Soil samples (0–20 cm depth)collected 11 months after the last soil amendment were analysed for: pH and EC,Kjeldahl-N, available-P, available-K, total organic carbon, humic substances,dehydrogenase, phosphatase, -glucosidase, urease andbenzoyl-argininamidehydrolysing protease (BAA-protease) activities. Generally, the application of the MWC and PSincreased orange yield when compared to control. Moreover, total organic carbonand humic substances significantly increased in soils treated with all theorganic amendments. Organic fertilisation increased the Kjeldahl-N andavailable-P contents of the soil. The application of the organic residues also causedsignificant increases in dehydrogenase, -glucosidase, urease andBAA-protease activities of the soil. Significant positive correlations (p <0.01) between these enzymatic activities and total organic carbon were foundforall treatments. Significant positive correlation between dehydrogenase, urease,-glucosidase, and BAA-protease and orange yield was also found. However,a clear inhibition of phosphatase activity was observed in soils treated withPS. The results indicate that the repeated application to the soil of moderateamounts of organic amendments has positive effects on the chemical andbiochemical properties of the soil, as well as on the orange yield.     

Effect of nitrogen,phosphorus and soil and crop residues management practices on maize (Zea mays L.) yield in ultisol of eastern Cameroon

The shortening of fallow period in several areas in tropical Africa has reduced soil fertility and exposed soils to erosion and run-off. Fertilizer application and crop conservation practices are needeed to sustain high crop yield and to conserve the natural resource base for upland crop production in the continent. Field trials were carried out to evaluate the effect of fertilizer application and soil and crop residues management practices on yield of maize (Zea mays L.) planted on a Plinthudult soil at Bertoua, Eastern Cameroon. Maize yields increased significantly with nitrogen and phosphorus fertilizer application. Under the rainfall pattern prevailing in the area, the amount of nitrogen required for maximum yield was higher in the second season. On the other hand, the amount of phosphorus required for maximum yield appeared to decrease with time. The burning of crop residues and weeds prior to planting together with no-till practive gave higher yield of maize than other soil and crop residues management practices.