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排序方式: 共有54条查询结果,搜索用时 15 毫秒
1.
运用一种植物油的系统分析方法测定蓖麻油的精细组分,这包括皂化,BF3-MeOH甲基化,GC-CIMS法测定脂肪酸碳链长度和不饱和度,AMP衍生化,GC-EIMS测定不饱和脂肪酸的双链位置,分析了蓖麻油的十一种脂肪酸组分,有五个为未知组分,并测定了其中三个组分的双链位置。  相似文献   
2.
Journal of Solid State Electrochemistry - This contribution described the electrochemical study of organosoluble gold nanoclusters (AuNCs).The AuNCs were characterized with UV-vis absorption...  相似文献   
3.
A novel copper‐catalyzed aerobic oxidative C(CO) C(alkyl) bond cleavage reaction of aryl alkyl ketones for C N bond formation is described. A series of acetophenone derivatives as well as more challenging aryl ketones with long‐chain alkyl substituents could be selectively cleaved and converted into the corresponding amides, which are frequently found in biologically active compounds and pharmaceuticals.  相似文献   
4.
A novel copper‐catalyzed aerobic oxidative C(CO)? C(alkyl) bond cleavage reaction of aryl alkyl ketones for C? N bond formation is described. A series of acetophenone derivatives as well as more challenging aryl ketones with long‐chain alkyl substituents could be selectively cleaved and converted into the corresponding amides, which are frequently found in biologically active compounds and pharmaceuticals.  相似文献   
5.
研究了Delannoy数与Schr?der数.利用分析方法和组合技巧,建立了任意多个Delannoy数乘积的一些和式公式,并对Schroder数的和式公式进行了类似的研究.  相似文献   
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A cationic cobalt(III)‐catalyzed direct C?H amidation of unactivated (hetero)arenes and alkenes by using 1,4,2‐dioxazol‐5‐ones as the amidating reagent has been developed. This transformation proceeds efficiently under external oxidant‐free conditions with a broad substrate scope. Moreover, 6‐arylpurine compounds, which often exhibit high potency in antimycobacterial, cytostatic, and anti‐HCV activities, can be smoothly amidated, thus offering a mild protocol for their late stage functionalization.  相似文献   
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This paper deals with a variable diffusion predator–prey model with additive Allee effect. A good understanding of the existence of steady states is gained for the case  σ=0. The result shows that the reduce problem has multiple solutions. Moreover, by applying the singular perturbation method, we give a proof of existence of large amplitude solutions when  σ is sufficiently small.  相似文献   
10.
Xu  Conghui  Yu  Yongguang  Chen  YangQuan  Lu  Zhenzhen 《Nonlinear dynamics》2020,101(3):1621-1634
Nonlinear Dynamics - In this paper, a generalized fractional-order SEIR model is proposed, denoted by SEIQRP model, which divided the population into susceptible, exposed, infectious, quarantined,...  相似文献   
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