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本文合成了含酰胺基团和不含酰胺基团的两类Gemini阳离子表面活性剂,测定了其表面活性参数,研究了酰胺基团对表面活性剂的表面活性和聚集行为的影响。结果表明,酰胺基团提高了Gemini阳离子表面活性剂的临界胶团浓度,降低了胶团聚集数,增强了胶团微极性,增大了表面活性剂的饱和吸附量。 相似文献
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对纯镍及其表面离子注钇样品在1000℃空气中的恒温氧化和循环氧化行为进行了研究。用扫描电镜(SEM)和透射电镜(TEM)对氧化膜的表面形貌及结构进行了观测。研究表明离子注钇极大地提高了金属镍的抗氧化性能。此外,用声发射(AE)技术研究了氧化膜/基体界面上缺陷的分布情况,并用激光拉曼(Raman)谱对注钇引起的膜内应力变化进行了测量。结果表明,离子注钇降低了NiO氧化膜的生长速率,减小了表面NiO的晶粒尺寸,降低了膜内压应力水平。同时,离子注钇还减小了氧化膜/基体界面缺陷的平均尺寸和数目,因此,极大地提高了镍表面NiO氧化膜的粘附性和保护性。 相似文献
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A series of binary and ternary rare earth complexes with para-substitued benzoic acids and 1,10-phenanthroline were synthesized. The phosphorescence spectra were measured and the lowest triplet state energies of ligands were determined, the phosphorescence lifetimes were obtained and intramolecular energy transfer mechanism between ligands was studied. The luminescence properties were also measured and were in agreement with the prediction. The energy match and intramolecular energy transfer process in these binary and ternary complexes were discussed in detail. 相似文献
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Gas chromatography-olfactometry analysis of the volatile compounds of two commercial Irish beef meats 总被引:1,自引:0,他引:1
The volatile flavour compounds of two commercial Irish beef meats (labelled as conventional and organic) were evaluated by gas chromatography-olfactometry and were identified by gas chromatography-mass spectrometry. The volatile compounds were isolated in a model mouth system. Gas chromatography-olfactometry was performed by a group of eight assessors using the detection frequency methodology. The odours of the detected compounds were described as well. Eighty-one volatile compounds were identified, 11 compounds of which possessed odour activity in the first beef sample and 14 of which in the second meat sample. Ten volatile flavour compounds were common to both: methanethiol, dimethyl sulphide, 2-butanone, ethyl acetate, 2- and 3-methylbutanal, an unknown compound, 2-octanone, decanal and benzothiazole. Two unknown compounds were only detected in the first sample while 2,3-pentanedione, 4-methyl-3-penten-2-one, 2-heptanone, dimethyl trisulphide and nonanal were only perceived in the second beef. Significant differences in terms of detection frequency, odour characteristics and in nature of the volatile flavour compounds were emphasised between the two samples. 相似文献
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Bünyemin OUT Burcu TOPALOLU AKSOY Süreyya Ouz TÜMAY Ahmet ENOCAK Serkan YELOT 《Turkish Journal of Chemistry》2020,44(1):48
Phenoxy- and naphthoxy-substituted bisphenol-bridged cyclic phosphazenes were synthesized in 2 steps and their thermal, photophysical, and electrochemical properties were investigated. The structures of the cyclic phosphazene compounds were determined by ESI-MS mass spectrometry and 1 H, 13 C, and 31 P NMR spectroscopies. The photophysical studies of phenoxy- and naphthoxy-substituted bridged cyclophosphazenes were investigated by means of absorption and fluorescence spectroscopies in different solvents. Thermal and electrochemical properties of the target compounds were also studied. Furthermore, the excimer emissions through intramolecular interactions in solution and in solid state were investigated by fluorescence spectroscopy and the theoretical calculations were performed in detail using DFT. 相似文献
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为了分析烤烟中游离氨基酸含量与烤烟香型、产地的关系,以国内14个烟草种植省份的138个调制后的烤烟中部叶片为材料,采用柱前衍生-超高效液相色谱-单重四极杆质谱法对烤烟中的20种游离氨基酸进行分析。方法表征结果显示该方法满足分析要求,适合烤烟中游离氨基酸的检测。对调制后烤烟中部叶片的游离氨基酸分析结果显示,烤烟的游离氨基酸含量在产地间差异很大(28.50%~94.20%),其中天冬酰胺、谷氨酰胺含量的相对标准偏差(RSD)超过80%;在3种典型香型(浓香型、清香型和中间香型)烤烟中,浓香型烤烟游离氨基酸含量的RSD大于其他两种香型。对同一香型的不同种植省份和同一省份不同香型的烤烟游离氨基酸分析结果显示,其含量呈现一定的规律。 相似文献
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Sanguisorba tannins are the major active ingredients in Sanguisorba ofJicinalis L. (Rosaceae), one of the most popular herbal medicines in China, is widely prescribed for hemostasis. In this study, three kinds of tannins extract from Sanguisorba officinalis L. (Rosaceae), and the metabolites in vivo and in vitro were detected and identified by high-pressure liquid chromatography, coupled with linear ion trap orbitrap tandem mass spectrometry (HPLC–LTQ–Orbitrap). For in vivo assessment, the rats were administered at a single dose of 150 mg/kg, after which 12 metabolites were found in urine, 6 metabolites were found in feces, and 8 metabolites were found in bile, while metabolites were barely found in plasma and tissues. For in vitro assessment, 100 μM Sanguisorba tannins were incubated with rat liver microsomes, liver cytosol, and feces, after which nine metabolites were found in intestinal microbiota and five metabolites were found in liver microsomes and liver cytosol. Moreover, the metabolic pathways of Sanguisorba tannins were proposed, which shed light on their mechanism. 相似文献
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采用溶胶-凝胶法制备了多孔氧化铝膜, 并通过DSC、TGA、SEM、N~2吸附和气体透过率测定等手段, 对膜的性能进行了表征。结果表明, 用这种方法制备的多孔氧化铝膜是一种均匀无裂痕和具有较窄孔径分布(约4nm)的膜材料。将此多孔氧化铝膜制成膜反应器后, 用于甲醇催化脱氢制甲醛的反应, 发现甲醇转化率比常规反应器有较大幅度的提高。同时首次尝试采用溶胶-凝胶法将催化活性组分直接负载到多孔氧化铝膜上, 从而得到了一种具有催化活性的多孔膜, 并考察了它的反应活性。文中对由这两种多孔膜及钯/陶瓷复合膜制成的反应器的特点进行了比较。 相似文献
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应用蛋白质组学双向凝胶电泳(Two-dimensional gel electrophoresis, 2DE)和质谱技术, 定量分析和鉴定了癫痫组(n=3)和正常组(n=3)脑组织的差异表达蛋白, 以从蛋白质水平上揭示癫痫病的发机制. 结果表明, 凝胶图谱可辨识2500~3000个蛋白点, 对21个显著差异表达蛋白点进行质谱鉴定和SwissProt数据库检索, 得到17个癫痫差异蛋白, 其中2个蛋白在癫痫组织中表达上调, 15个蛋白表达下调. 部分蛋白与癫痫的关系属首次报道. 这些蛋白与癫痫的发生发展相关, 可能成为癫痫的分子标志物和药物治疗的靶向蛋白. 相似文献
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催化柴油中的酚类化合物及其对柴油安定性的影响 总被引:15,自引:3,他引:12
催化裂化柴油用10%的碱-醇(5:1体积)萃取,得到了0.5~0.8W%(相对柴油)的酚的混合物。通过色质分析,鉴定出了69种酚,其结构比文献报道的从催化柴油中分离的酚的结构要复杂得多。这些酚的混合物对柴油的颜色和沉渣有明显的影响。元素分析表明其中还含有硫氮化合物。 相似文献
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《Analytical letters》2012,45(9):1511-1523
Anion and cation exchange high-performance liquid chromatography (HPLC) combined with inductively coupled plasma-mass spectrometry (ICP-MS) were used for speciation of selenium in supplements. All the parameters in the extraction, separation, and determination procedures were optimized. Recovery studies for the selenium species from the anion and cation exchange columns were performed and there were no analyte losses. Limits of detection for selenium(IV), selenium(VI), Se in selenomethionine, and Se in selenocystine were 0.85, 0.68, 0.84, and 0.99 nanogram per milliliter, respectively. Six brands were analyzed to identify and quantify the selenium species present, and the results found were compared with the values given on the labels. The selenium species matched the labeled species for four brands, whereas two brands were found to contain inorganic Se(VI) in contrast with the labeled claim of selenomethionine. 相似文献