GC/MS解析中二苯硫脲的中性丢失

温和条件常温常压下 ,苯胺与CS2 在AlCl3 催化作用下反应 ,对反应混合物用乙醇进行重结晶获得白色片状晶体 ,GC/MS分析表明该晶体为异硫氰酸苯酯。然而 ,用熔点测定、HPLC/MS/MS ,FTIR ,UV和1HNMR等手段对此晶体进行分析 ,确定其为二苯硫脲。结合GC/FTIR谱图 ,研究了二苯硫脲的质谱裂解机理。实验结果表明二苯硫脲质谱裂解中可能发生了中性丢失 ,丢失了中性分子苯胺 ,生成的异硫氰酸苯酯分子离子由于π电子共轭而致稳。此机理同样能合理解释二苯脲和二萘硫脲的GC/MS谱图中只出现异氰酸苯酯和异硫氰酸萘酯分子离子峰的现象。     

萘油制备新型水煤浆添加剂的研究

研究了如何利用萘油中的有效成分合成出性能良好的水煤浆添加剂。通过合理的正交试验设计和多元线性回归分析方法得到了合成萘油添加剂的较佳工艺条件,即在75 g的萘油中,加入浓H2SO4 30 mL,在160 ℃时磺化2 h;加入HCHO 25 mL,在105 ℃时缩合1.5 h。利用实验合成的萘油添加剂与纯萘磺酸甲醛缩合物作添加剂分别对庞庄煤进行制浆实验。结果表明,萘油添加剂性能良好,可显著降低萘油添加剂的成本。应用傅立叶变换红外光谱对萘油添加剂的结构进行了分析,测出萘油添加剂主要为含有－CH2－,－SO3－等基团的芳香族化合物。对萘油添加剂改善水煤浆性能的作用机理进行了初步探讨。     

Synthesis of Fragment-Imprinted Microspheres of 2,6-Dichloropyrimidine as Templates and Determination of Sulfonamides in Milk Samples

Fragment-imprinted microspheres (FIMs) were prepared by suspension polymerization. 2,6-Dichloropyrimidine was used as the template molecule instead of sulfonamides, methacrylic acid and styrene were the mixed functional monomers, ethylene dimethacrylate was the crosslinking agent, and azodiisobutyronitrile was the initiator. The optimum conditions were obtained by an orthogonal experiment. The maximum adsorption was obtained under the optimum conditions. The adsorption by FIMs was 7.02 mg g⁻¹, whereas the adsorption by non-FIMs was 5.41 mg g⁻¹. A method for the simultaneous determination of five sulfonamides from milk samples by fragment imprinted-solid phase extraction coupled with HPLC was developed. The recoveries for the five sulfonamide extractions were 89.7–97.6 % with relative standard deviations of 1.79–3.02 %, indicating the suitability of the prepared FIMs for sulfonamide extraction.

     

Synthesis of Fragment-Imprinted Microspheres of 2,6-Dichloropyrimidine as Templates and Determination of Sulfonamides in Milk Samples

Fragment-imprinted microspheres (FIMs) were prepared by suspension polymerization. 2,6-Dichloropyrimidine was used as the template molecule instead of sulfonamides, methacrylic acid and styrene were the mixed functional monomers, ethylene dimethacrylate was the crosslinking agent, and azodiisobutyronitrile was the initiator. The optimum conditions were obtained by an orthogonal experiment. The maximum adsorption was obtained under the optimum conditions. The adsorption by FIMs was 7.02 mg g^?1, whereas the adsorption by non-FIMs was 5.41 mg g^?1. A method for the simultaneous determination of five sulfonamides from milk samples by fragment imprinted-solid phase extraction coupled with HPLC was developed. The recoveries for the five sulfonamide extractions were 89.7–97.6 % with relative standard deviations of 1.79–3.02 %, indicating the suitability of the prepared FIMs for sulfonamide extraction.     

The influence of X-semipermutability of subgroups on the structure of finite groups

Let A be a subgroup of a group G and X be a nonempty subset of G. A is said to be X-semipermutable in G if A has a supplement T in G such that A is X-permutable with every subgroup of T. In this paper, we investigate further the influence of X-semipermutability of some subgroups on the structure of finite groups. Some new criteria for a group G to be supersoluble or p-nilpotent are obtained.     

Conformational effect on fluorescence emission of tetraphenylethylene-based metallacycles

Herein, we designed and constructed two metallacycles, 1 and 2, to illustrate the conformational effect of isomeric AIE fluorophores on the platform of supramolecular coordination complexes (SCCs). Speci?cally, the dangling phenyl rings in TPE units of the metallacycle 1 align completely outside the main cyclic structure, while in the metallacycle 2, these phenyl rings align half inside and half outside. The experimental results showed that two metallacycles exhibited different behaviors in terms of AIE fluorescence and chemical sensing, which could be attributed to the subtle structural difference of the TPE units. This work represents the unification of topics such as self-assembly, AIE, and chemical sensing, and further promotes the understanding for the structure-property relationship of isomeric AIE fluorophores.     

Crown ether-based cryptand/tropylium cation inclusion complexes

Host–guest complexation between crown ether-based cryptand hosts and a carbonium ion, tropylium hexafluorophosphate was studied. ¹H NMR, NOESY NMR, and electrospray ionization mass spectrometry were employed to characterize these inclusion complexes. The contrast tests of ¹H NMR and association constants indicated that cryptands are much better hosts for tropylium hexafluorophosphate than the corresponding simple crown ethers. C–H?O hydrogen bonding, face-to-face π-stacking interactions, and charge-transfer interactions are thought to be the main driving forces for the formation of these host–guest complexes. These multiple non-covalent interactions may jointly contribute to the complex formation and considerably reinforce the complex stability. Moreover, the complexation between dibenzo-24-crown-8-based cryptand 4 and tropylium hexafluorophosphate 7 can be reversibly controlled by adding KPF₆ and then DB18C6 in 1:1 acetonitrile/chloroform, providing a new cation-responsive host–guest recognition motif for supramolecular chemistry.     

Hyperspectral remote sensing image classification based on decision level fusion

To apply decision level fusion to hyperspectral remote sensing (HRS) image classification,three decision level fusion strategies are experimented on and compared,namely,linear consensus algorithm,improved evidence theory,and the proposed support vector machine (SVM) combiner.To evaluate the effects of the input features on classification performance,four schemes are used to organize input features for member classifiers.In the experiment,by using the operational modular imaging spectrometer (OMIS) II HRS im...     

FeSiF66H2O晶体的基态能级和零场分裂参量

由单晶的中子衍射方法得到FeS_iF₆6H₂O的晶体结构,这种晶体结构可以用S_iF^6-和Fe(H₂O)⁺⁺两个离子来描述,而局域三角对称的Fe(H₂O)⁺⁺离子反映了这种晶体的主要光谱性质利用不可约张量的理论,构成了晶体场和自旋轨道相互作用哈密顿完全对角化矩阵因此,由完全对角化的晶体场和自旋轨道相互作用哈密顿矩阵和电子顺磁共振的理论公式来求出晶体FeS_iF₆6H₂O中Fe²⁺离子的电子顺磁共振零场分裂参量D和Fa并研究了低自旋³L态对电子顺磁共振(EPR)零场分裂参量的贡献结果显示低自旋³L态对电子顺磁共振的零场分裂参量的贡献是较强的理论计算的结果与实验值是相符的.     

LB膜的制膜条件优化及其对光学性能的影响

通过紫外-可见吸收光谱、二次谐波振荡和稳态荧光的测量,研究了半花菁(DAEP)Langmuir-Blodgett(LB)膜在不同制膜条件(压膜速度、半花菁和花生酸混合、亚相中加入碘离子)下,LB膜样品中半花菁分子的聚集体性质的改变和对非线性光学性能的影响.实验发现,纯半花菁LB膜中分子形成H-聚集体,从而导致吸收峰、荧光峰的蓝移和分子二阶非线性极化率β的减少.分子聚集程度的减少和分子二阶非线性系数β的增加可以通过增大压膜速度、半花菁和花生酸混合、亚相中加入碘离子等方法实现.