A calix[8]arene-bonded gel silica stationary phase(DCABS) was prepared by using coupling reagent(KH560). Its structure was characterized by FTIR, elemental analysis and thermal analysis. The chromatographic performanc...A calix[8]arene-bonded gel silica stationary phase(DCABS) was prepared by using coupling reagent(KH560). Its structure was characterized by FTIR, elemental analysis and thermal analysis. The chromatographic performance of DCABS was studied by using different solutes as probes and stationary phases as reference. The results show that the new material has an excellent reversed-phase chromatographic property. The new bonded phase can provide various sites for analytes, such as the hydrophobic interaction, hydrogen-bonding, π-π, electrostatic interactions. Meanwhile, it was observed that the chromatographic performance of DCABS is partially different from CABS because of elimination of the butyl groups.展开更多
Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand,...Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand, direct condensation and pyrolysis of naphtho[1,8-de][1,2,3]triazine with ethylisocyanate, phenylisocyanate and their isothiocayanates, benzoylisothiocyanate and thiourea at 150-160 ℃ or under microwaves irradiation produced the corresponding naphthopyrimidin-2-one derivatives.展开更多
Introduction: Agriculture is the focus of sustainable development and food security in Morocco, contributing 14% to the national economy and its socio-economic impact depends on agro-climatic conditions and the availa...Introduction: Agriculture is the focus of sustainable development and food security in Morocco, contributing 14% to the national economy and its socio-economic impact depends on agro-climatic conditions and the availability of water resources. The objective of this work is to demonstrate that agriculture in Morocco, and especially in the Tadla region, is distributed according to the availability of underground water. Method: This work was carried out in the transition zone between the phosphate plateau and the plain of Tadla, a site of more than 124,000 ha. To achieve the objectives set, we used Landsat-8 OLI (Operational Land Imager) data sharpened to 15 m. The Support Vector Machine (SVM) classifications were applied to the 10-period Normalized Difference Vegetation Index (NDVI) series. Results: It is shown that agriculture in Morocco is highly dependent on irrigation. In the classified map, it can be observed that the southern region, a zone with a semi-arid climate, which generally relies on irrigation, is very developed in agriculture, whereas in the north most of the soil is bared with cereals that mainly depend on rainfall. Conclusion: The possible water shortage in the region puts food availability in Morocco at risk of inadequacy. Food security depends on the availability of water, a natural resource at risk of extinction. Therefore, strategies to reduce the risk of agricultural drought must be at the forefront of Moroccan policies.展开更多
文摘A calix[8]arene-bonded gel silica stationary phase(DCABS) was prepared by using coupling reagent(KH560). Its structure was characterized by FTIR, elemental analysis and thermal analysis. The chromatographic performance of DCABS was studied by using different solutes as probes and stationary phases as reference. The results show that the new material has an excellent reversed-phase chromatographic property. The new bonded phase can provide various sites for analytes, such as the hydrophobic interaction, hydrogen-bonding, π-π, electrostatic interactions. Meanwhile, it was observed that the chromatographic performance of DCABS is partially different from CABS because of elimination of the butyl groups.
文摘采用AB-8大孔树脂吸附分离橄榄油加工废液中的橄榄多酚。分别考察了静态吸附、静态解吸和动态洗脱工艺条件。结果表明:适宜的静态吸附条件为在30℃下用1.5 g预处理的树脂吸附20 m L橄榄多酚质量浓度为1.52 mg/m L的粗提稀释液,吸附3 h时吸附量可达14.43 mg/g;动态洗脱橄榄多酚的适宜条件为洗脱流速1.0 m L/min,依次用蒸馏水、70%乙醇溶液、90%乙醇溶液进行分段洗脱。在静态吸附和动态分段洗脱的组合条件下,纯化所得橄榄多酚的纯度为56.44%,为粗提稀释液的7.93倍。
文摘Gas-phase thermolysis of 1-ethoxycarbonyl-benzotriazole under static, FVP and microwaves condition yielded N^1 and NZ-ethylbenzotriazole, 2-ethoxy-1,3-benzooxazole, biphenylene and oxazolidin-2-one. On the other hand, direct condensation and pyrolysis of naphtho[1,8-de][1,2,3]triazine with ethylisocyanate, phenylisocyanate and their isothiocayanates, benzoylisothiocyanate and thiourea at 150-160 ℃ or under microwaves irradiation produced the corresponding naphthopyrimidin-2-one derivatives.
文摘Introduction: Agriculture is the focus of sustainable development and food security in Morocco, contributing 14% to the national economy and its socio-economic impact depends on agro-climatic conditions and the availability of water resources. The objective of this work is to demonstrate that agriculture in Morocco, and especially in the Tadla region, is distributed according to the availability of underground water. Method: This work was carried out in the transition zone between the phosphate plateau and the plain of Tadla, a site of more than 124,000 ha. To achieve the objectives set, we used Landsat-8 OLI (Operational Land Imager) data sharpened to 15 m. The Support Vector Machine (SVM) classifications were applied to the 10-period Normalized Difference Vegetation Index (NDVI) series. Results: It is shown that agriculture in Morocco is highly dependent on irrigation. In the classified map, it can be observed that the southern region, a zone with a semi-arid climate, which generally relies on irrigation, is very developed in agriculture, whereas in the north most of the soil is bared with cereals that mainly depend on rainfall. Conclusion: The possible water shortage in the region puts food availability in Morocco at risk of inadequacy. Food security depends on the availability of water, a natural resource at risk of extinction. Therefore, strategies to reduce the risk of agricultural drought must be at the forefront of Moroccan policies.
