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21.
用抑制型离子色谱法测定白酒中的F~-、cl~-、NO_2~-、H_2PO_4~-、NO_3~-。流动相为4mmoL/L Na_2CO_3-3mmoL/L NaHCO_3混合溶液,流速为1.5mL/min,进样量为0.5mL,在最佳色谱条件下,5种无机阴离子10min内实现基线分离。F~-、cl~-、NO_2~-、H_2PO_4~-、NO_3~-的检出限分别为0.008、0.012、0.030、0.068、0.077mg/L。测定结果的相对标准偏差分别为1.86%、1.30%、2.06%、1.82%、1.50%,回收率分别为108.0%、94.0%、101.0%、98.7%、94.4%。 相似文献
22.
Bismuth film electrode (BiFE) was shown to be an attractive alternative to common mercury film electrode (MFE) for anodic stripping voltammetric measurements. In this study, bismuth film, that was in situ deposited onto glassy carbon electrode, was used to detect zinc content of milkvetch, used in traditional Chinese medicine. Variables affecting the response have been evaluated and optimized. Experimental results showed a high response, with a good linearity (between 0.5 × 10−6 mol L−1 and 3 × 10−6 mol L−1) a good precision (R.S.D. = 3.58%) and a low detection limit (9.6 × 10−9 mol L−1 with a 120 s anodic). The anodic stripping performance makes the bismuth film electrode very desirable for measurements of trace nutritive element zinc in milkvetch and should impart possible restrictions on the use of mercury electrode. 相似文献
23.
在三重桥氧三核铬羧酸配合物的系列研究中,采用与铬的一元羧酸配合物类似的实验条件,以丙二酸为配体合成了不同构型的配合物[Cr(C3H2O4)(H2O)4)][Cr(C3H2O4)2(H2O)2]·4H2O,通过X射线衍射测定了其单晶结构,并对-COO的配位方式作了讨论,还研究了配合物的红外光谱、拉曼光谱、紫外可见光谱、质谱、磁化率等性质,探讨了性质与结构的关系,并由此论证了二元羧酸和铬形成的双齿螯合构型化合物的稳定性. 相似文献
24.
在折衍混合光学系统的加工和装配过程中,折、衍器件间的对中精度严重影响混合器件的质量和性能,但是由于衍射器件与传统折射器件的显着差异,传统的对中手段已不再适用,如何简便实现二者的精确对中是混合光学系统实用化过程中亟待解决的问题之一.本文提出利用干涉原理简便地实现衍射器件与折射器件的高精度对中,理论分析和实验结果表明该对中装校方法是有效可行的,可以满足光学系统的对中要求。 相似文献
25.
本文用拉曼光谱法测定了天花粉蛋白在pH为1.9~11.5范围内二级结构的变化。结果表明,随pH值的增加,α-螺旋略有减少,β-折叠略有增加,而无序结构没有明显变化。 相似文献
26.
Dr. Hao Sun Dr. Wei Cao Dr. Nanzhi Zang Dr. Tristan D. Clemons Georg M. Scheutz Ziying Hu Dr. Matthew P. Thompson Yifei Liang Maria Vratsanos Xuhao Zhou Wonmin Choi Prof. Dr. Brent S. Sumerlin Prof. Dr. Samuel I. Stupp Prof. Dr. Nathan C. Gianneschi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(43):19298-19304
Herein, we report the photoinitiated polymerization-induced self-assembly (photo-PISA) of spherical micelles consisting of proapoptotic peptide–polymer amphiphiles. The one-pot synthetic approach yielded micellar nanoparticles at high concentrations and at scale (150 mg mL−1) with tunable peptide loadings up to 48 wt. %. The size of the micellar nanoparticles was tuned by varying the lengths of hydrophobic and hydrophilic building blocks. Critically, the peptide-functionalized nanoparticles imbued the proapoptotic “KLA” peptides (amino acid sequence: KLAKLAKKLAKLAK) with two key properties otherwise not inherent to the sequence: 1) proteolytic resistance compared to the oligopeptide alone; 2) significantly enhanced cell uptake by multivalent display of KLA peptide brushes. The result was demonstrated improved apoptosis efficiency in HeLa cells. These results highlight the potential of photo-PISA in the large-scale synthesis of functional, proteolytically resistant peptide–polymer conjugates for intracellular delivery. 相似文献
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28.
Nitrogen and phosphorus co‐doped hierarchical micro/mesoporous carbon (N,P‐MMC) was prepared by simple thermal treatment of freeze‐dried okra in the absence of any other additives. The 0.96 wt % of N and 1.47 wt % of P were simultaneously introduced into the graphitic framework of N,P‐MMC, which also possesses hierarchical porous structure with mesopores centered at 3.6 nm and micropores centered at 0.79 nm. Most importantly, N,P‐MMC carbon exhibits excellent catalytic activity for electrocatalytic reduction of H2O2, resulting in a new strategy to construct non‐enzymatic H2O2 sensor. The N,P‐MMC‐based H2O2 sensor displays two linear detection range about 0.1 mM–10 mM (R2=0.9993) and 20 mM–200 mM (R2=0.9989), respectively. The detection limit is estimated to be 6.8 μM at a signal‐to‐noise ratio of 3. These findings provide insights into synthesizing functional heteroatoms doped porous carbon materials for biosensing applications. 相似文献
29.
Ultrasound can be used as a carrier to realize wireless communication to and from a metal-enclosed space, which has the characteristics such as immunity to the electromagnetic shielding effect and non-destructive penetration
of metal obstacles. This paper firstly reviews the previous studies in the field of ultrasonic wireless communication through metal barriers, and summarizes their achievements and the existing problems. Secondly, an overview of the research methods involved in studying the characteristic of acoustic-electric channel is presented, and the principles are introduced for the actual measurement method, equivalent circuit method, ABCD parameter method, finite element analysis method and time-domain finite difference method. Then, an overview of the communication algorithms are presented such as orthogonal frequency division multiplexing (OFDM), single-carrier frequency domain equalization and multiple input multiple output OFDM. Finally, the potential future study are proposed in light of the trend of development and unsolved problems. 相似文献
30.