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Ting Sun Yuwan Fan Peizheng Fan Fengyun Geng Peiyu Chen Feng Zhao 《Journal of separation science》2019,42(12):2131-2139
In this work, nanocomposites of reduced graphene oxide coated with ZnO were synthesized using a hydrothermal reduction strategy. Nanocomposite was then used as a sorbent for microextraction in a packed syringe, and its application to the extraction of carbamate pesticides from juice samples prior to high‐performance liquid chromatography detection was demonstrated. Factors affecting the enrichment efficiency of the microextraction in a packed syringe procedure were optimized, which included desorption conditions, sample pH, salting‐out effect, washing solution, and sample cycles. Under optimal conditions, the prepared materials exhibited excellent enrichment efficiency for carbamate pesticides. Good linearity existed in the concentration range of 0.5–200 ng/mL, with correlation coefficients of 0.9991–0.9997. The limits of detection of these carbamate pesticides were in the range of 0.23–1.21 ng/mL, and the average recoveries of the analytes at two spiked levels for real‐sample analysis ranged from 90.5 to 104.2% with relative standard deviations of 3.6–5.9%. 相似文献
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含多巴胺的贻贝仿生聚氨酯 总被引:1,自引:0,他引:1
将具有神奇黏附效果的贻贝黏附蛋白中的功能元——儿茶酚(catechol)与具有结构可设计、简单易得、低成本的聚氨酯相结合,制备新型高性能的贻贝仿生聚氨酯黏附材料.首先,通过异氰酸酯化学合成了含羧基的聚氨酯,接着通过碳二亚胺化学将含有儿茶酚功能团的多巴胺(dopamine)和含羧基的聚氨酯相结合制备了含多巴胺的聚氨酯.经过傅立叶转换红外光谱(FTIR)、核磁共振(NMR)和紫外-可见分光光度仪(UV-Vis)等分析测试研究结果表明,多巴胺确实已被引入到聚氨酯中;同时,通过测试搭接剪切强度研究了其粘接性能,结果表明含多巴胺的聚氨酯相对于含羧基的聚氨酯的粘接性能得到大幅提高,其对金属基材的粘接强度提高了30%左右,达到5.2MPa,可以与贻贝黏附蛋白相媲美. 相似文献
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In this paper, we firstly give some basic properties on quasi-cotilting modules. With the help of these properties, we obtain a Quasi-cotilting Theorem (see Theorem 2.8). In particular, the Cotilting Theorem in [5] is a corollary of our result. Finally, we introduce a new notion, hereditary quasi-cotilting modules, and mainly prove that the class consisting of all Δ-reflexive modules for a hereditary quasi-cotilting module is closed under submodules. 相似文献
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The equimolar quaternary CrVTiAl is not only a potential spin filter, but also a light-weight high entropy alloy. The excellent performance strongly depends on the order degree. We use the ab initio calculation to investigate the structural, magnetic, elastic properties of CrVTiAl as a function of the order degree describing phase from full disorder A2 to DO3, B2, and L21 to full order Y-type (LiMgPdSn-type) structure. The Cr-Al bonding plays a key role in the local magnetic moments, further induces the increasing lattice parameter and decreasing elastic constants. Furthermore, the effect of preferred sites on mechanical properties is discussed. 相似文献
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铜(II)化合物作用下2-綦胺的氧化偶合反应 总被引:1,自引:0,他引:1
2-萘胺(1)在甲醇中与铜胺络合物[x(CuCl_2):x(苄胺或乙醇胺)=2:1]室温 下反应得到产率为74%的1,1'-联-2-萘胺(2)。在醋酸铜、硝酸铜或高氯酸铜的催 化下,1在甲醇中被氢气氧化为2-氨基-1,4-萘醌-4-2'-萘亚胺(3),产率86%。 用X-ray单晶衍射证实3的乙酰化产物结构为2-乙酰氨基-1,4-萘醌-E-4-2'-萘亚胺 (4)。循环伏安研究表明,铜(II)化合物的氧化反应选择性与其还原峰电位有 关。电喷雾质谱的分析表明1,2-萘醌-2-亚胺(6)是生成3的中间体。 相似文献
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Zhou DD Han K Zhang P Harding LB Davis MJ Skodje RT 《The journal of physical chemistry. A》2012,116(9):2089-2100
The HO(2) + HO(2) → H(2)O(2) + O(2) chemical reaction is studied using statistical rate theory in conjunction with high level ab initio electronic structure calculations. A new theoretical rate coefficient is generated that is appropriate for both high and low temperature regimes. The transition state region for the ground triplet potential energy surface is characterized using the CASPT2/CBS/aug-cc-pVTZ method with 14 active electrons and 10 active orbitals. The reaction is found to proceed through an intermediate complex bound by approximately 9.79 kcal/mol. There is no potential barrier in the entrance channel, although the free energy barrier was determined using a large Monte Carlo sampling of the HO(2) orientations. The inner (tight) transition state lies below the entrance threshold. It is found that this inner transition state exhibits two saddle points corresponding to torsional conformations of the complex. A unified treatment based on vibrational adiabatic theory is presented that permits the reaction to occur on an equal footing for any value of the torsional angle. The quantum tunneling is also reformulated based on this new approach. The rate coefficient obtained is in good agreement with low temperature experimental results but is significantly lower than the results of shock tube experiments for high temperatures. 相似文献
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高氯酸盐是水环境中一种典型的难降解的持久性无机污染物,具有高度水溶性及扩散性。地表水及地下水中的高氯酸盐可以通过多种方式保存在食物和饮用水中,对人体健康造成严重危害。针对传统的高氯酸盐检测技术操作复杂、检测周期长、成本高且不便于即时检测等问题,本文提出了一种智能手机快速测定高氯酸盐含量的新方法,以充分发挥其能简便、准确、快速现场检测水高氯酸盐的优势。本研究采用由3D打印箱、扩散板、补光灯和智能手机构建的数字图像比色装置完成了水中高氯酸盐浓度的快速检测,探讨了手机型号、光源、干扰离子对数字图像比色装置检测结果R(红)、G(绿)、B(蓝)值的影响。结果表明,以R-通道数字信号值作为测定值时,高氯酸盐在0 μg/L~600 μg/L浓度范围内呈良好的线性关系,线性方程为y=-0.1505 x+150.66,相关系数为R2=0.995,加标回收率为96~107%,检出限为27.7 μg/L,测定限为88 μg/L。选择白光、iPhone 11检测两组不同浓度高氯酸盐的实际水样,以探究重现性,测定结果的相对标准偏差为3.2%~4.0%,回收率为95%-107%,本方法具有一定的可行性和准确性,为现场快速测定水中高氯酸盐提供了一个新思路。 相似文献