共查询到20条相似文献,搜索用时 31 毫秒
1.
利用电动态平衡技术,将单个带电煤颗粒悬浮在样品池中,可以实现煤颗粒燃烧过程的原位微观研究。本文简要介绍了电动态平衡技术的原理和相关的操作方法,总结了该技术应用于煤燃烧研究的进展,进一步探讨了结合时间分辨光谱技术研究煤燃烧物理化学过程细节的可行性与发展前景。目的在于向国内研究者介绍这一新技术并激发更多的研究兴趣。 相似文献
2.
Noemí Echegaray Mirian Pateiro Paulo E. S. Munekata Jos M. Lorenzo Zakariya Chabani Mohamed A. Farag Rubn Domínguez 《Molecules (Basel, Switzerland)》2021,26(13)
At present, a wide variety of analytical methods is available to measure antioxidant capacity. However, this great diversity is not reflected in the analysis of meat and meat products, as there are a limited number of studies on determining this parameter in this complex food matrix. Despite this, and due to the interest in antioxidants that prevent oxidation reactions, the identification of antioxidants in meat and meat products is of special importance to the meat industry. For this reason, this review compiled the main antioxidant capacity assays employed in meat and meat products, to date, describing their foundations, and showing both their advantages and limitations. This review also looked at the different applications of antioxidant properties in meat and meat products. In this sense, the suitability of using these methodologies has been demonstrated in different investigations related to these foods. 相似文献
3.
4.
A. Maroto Ricard Boqué Jordi Riu F. Xavier Rius 《Accreditation and quality assurance》2002,7(3):90-94
The bias of an analytical procedure is calculated in the assessment of trueness. If this experimental bias is not significant,
we assume that the procedure is unbiased and, consequently, the results obtained with this procedure are not corrected for
this bias. However, when assessing trueness there is always a probability of incorrectly concluding that the experimental
bias is not significant. Therefore, non-significant experimental bias should be included as a component of uncertainty. In
this paper, we have studied if it is always necessary to include this term and which is the best approach to include this
bias in the uncertainty budget. To answer these questions, we have used the Monte-Carlo method to simulate the assessment
of trueness of biased procedures and the future results these procedures provide. The results show that non-significant experimental
bias should be included as a component of uncertainty when the uncertainty of this bias represents at least a 30% of the overall
uncertainty.
Received: 29 May 2001 Accepted: 10 December 2001 相似文献
5.
ABEEM-σπ模型在典型Diels-Alder反应立体选择性上的应用 总被引:1,自引:0,他引:1
利用ABEEM-σπ模型对Diels-Alder反应进行了理论研究,通过计算原子和π键区域的局域软度值,应用局域软度理论对典型的Diels-Alder反应的较高立体选择性给出了合理解释. 相似文献
6.
7.
Pablo Froimowicz Mohamed Naceur Belgacem Miriam C. Strumia 《European Polymer Journal》2008,44(12):4092-4097
A general procedure to increase the amount of photoreactive chromophore groups per oligoether chain is presented. In this work, a photoreactive macromonomer with four functionalities was synthesized by a four-step synthetic pathway with high yield. The photochemical behavior of this compound was studied with a view to obtaining polymeric networks. The significant advantage in this strategy is that the preparation of this material has as last operation, the obtaining and processing of polymer as thin film. In this way, the synthetic strategy based on assembling: (i) the polyether chains, (ii) a film forming backbone, and (iii) a photoactive moiety to be used for cross-linking, seems a viable solution to the problem of the continuous processing of materials. 相似文献
8.
《Analytical letters》2012,45(10):905-913
Abstract Recent advances in column and instrument technology have made the development of d new generation of high-resolution microcolumn liquid chromatography possible. In addition to offering reduced solvent consumption, this chromatographic technique also yields higher mass sensitivities than those in conventional systems. In this study, the applicability of this technique to the analysis of polycyclic aromatic hydrocarbons (PAH) is investigated. PAH in the extract from diesel particulate matter were analyzed to demonstrate the utility of this approach combined with the computer-assisted retention prediction. The technique proposed in this study makes very clean and high cost-performance environmental analysis possible. 相似文献
9.
简化柱切换技术在高浓度基体存在下测定痕量离子的研究 总被引:1,自引:0,他引:1
建立了适用于高浓度基体存在下测定痕量离子的简化柱切换技术。通过分析淋洗液浓度对待测离子色谱峰保留时间的影响 ,指出可使用高浓度淋洗液抑制色谱峰漂移 ,并通过实验案例提出了针对不同样品采取的不同策略。 相似文献
10.
长期以来,有机磷化学研究的核心内容主要集中在σ3和σ4的有机磷化合物及其衍生物方面,而低配位的有机磷化合物的研究则远远落后.本文简要综述了目前低配位的有机磷化合物σ1,λ1-亚膦烯、σ1,λ3-膦炔、σ2,λ3-膦烯和σ2,λ3-膦杂苯研究的最新进展,包括它们的合成及其在均相催化和材料等方面的应用. 相似文献
11.
A novel particle separation method based on induced‐charge electro‐osmotic flow and polarizability of dielectric particles 下载免费PDF全文
A new microfluidic method of particle separation was proposed and studied theoretically in this paper. This method is based on the induced charge electro‐osmotic flow (ICEOF) and polarizability of dielectric particles. In this method, a pair of metal plates is embedded on the side channel walls to create a region of circulating flows under applied electric field. When a dielectric particle enters this region, the vortices produced by ICEOF around the particle will interact with the circulating flows produced by the metal plates. Such hydrodynamic interaction influences the particle's trajectory, and may result in the particle being trapped in the flow circulating zone or passing through this flow circulating zone. Because the hydrodynamic interaction is sensitive to the applied electric field, and the polarizability and the size of the particles, separation of different particles can be realized by controlling these parameters. Comparing with electrophoresis and dielectrophoresis methods, this strategy presented in this paper is simple and sensitive. 相似文献
12.
Susanna H. Wood Dr. Stephen Etridge Dr. Alan R. Kennedy Prof. Jonathan M. Percy Dr. David J. Nelson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(21):5574-5585
The reaction of enol esters with SelectFluor is facile and leads to the corresponding α-fluoroketones under mild conditions and, as a result, this route is commonly employed for the synthesis of medicinally important compounds such as fluorinated steroids. However, despite the use of this methodology in synthesis, the mechanism of this reaction and the influence of structure on reactivity are unclear. A rigorous mechanistic study of the fluorination of these substrates is presented, informed primarily by detailed and robust kinetic experiments. The results of this study implicate a polar two-electron process via an oxygen-stabilised carbenium species, rather than a single-electron process involving radical intermediates. The structure–reactivity relationships revealed here will assist synthetic chemists in deploying this type of methodology in the syntheses of α-fluoroketones. 相似文献
13.
二甲戊乐(penoxalin)系甲苯胺类除草剂,原药为橙黄色固体,熔点56-58℃,在水中溶解度0.3mg/L(20℃),易溶于氯代烃和芳香烃溶剂中。二甲戊乐灵的分子式是C13H19N3O4,相对分子质量为281,分子结构式如右所示。二甲戊乐灵对大白鼠急性口服LD501.25g/kg(工业品),2.93g/kg(乳剂)。 相似文献
14.
Dong Xin Zhao Zhong Xian Huang 《中国化学快报》2007,18(3):355-356
For better understanding the chemical or biological information of ZNF191(243-368), we expressed the fusion protein of GST and ZNF191(243-368), and used it to obtain the binding DNA sequence of this zinc finger protein. But in the process of expression and purification, we found this fusion protein slowly degradated. For resolving this problem, we simultaneously added charged amino acids L-Arg and L-Glu to the solution of fusion protein, and demonstrated that this method can dramatically increase the stability of this fusion protein. This method can make the fusion protein suitable for the continuous works, especially for situations where high protein concentration and long-term stability without precipitate and degradation of protein are required. 相似文献
15.
With the development of the global economy,the safety of agricultural production has attracted intense attention.To minimize the risk of harmful ingredients in the whole industry chain,it is very necessary to cover the entire process of safety inspections from planting to production to environmental management.Fluorescence sensing as a promising and powerful screening tool is widely used for the detection of ions,toxic gases,biological molecules and so on.However,traditional fluorescent probes often suffer from aggregation-induced quenching(ACQ)effects,which limits their practical applications.In this regard,aggregation-induced emission luminogens(AIEgens)can perfectly address this notorious issue and have shown great potential in agricultural safety analysis.In this review,we briefly summarize their applications in agricultural safety monitoring,including the fabrication of agricultural film,agricultural sewage treatment and selective detection of harmful residues in agricultural products.The challenge and future development of AIEgens in this field are also discussed and highlighted.Hopefully,this review can inspire more researchers to participate in this fascinating area. 相似文献
16.
17.
考虑到毛细管色谱分析过程中径向浓度梯度对传质过程的影响,建立了相应的色谱质量平衡模型,模仿Giddings的假设,将模型适当化简,并通过数学变换的方法得到了流出曲线的一级矩及二、三级中心矩表达式。结果表明,溶质的径向扩散不仅对柱效、峰展宽、峰形特征等有影响,而且对溶质的保留时间也有一定的影响。 相似文献
18.
《Chemie in Unserer Zeit》2017,51(6):392-400
In this article we first discuss the NMR pulse sequence HMBC (heteronuclear multiple bond correlation) and demonstrate its importance for the final structure verification of the natural product cytisine. The 1H‐, 13C‐, COSY‐ und HSQC‐spectra of this compound have been shown in the first two articles of this series. After this we explain the physics of the NOESY‐experiment (nuclear Overhauser effect spectroscopy) and apply this for the stereochemical assignment of the proton signals. A correlation diagram between NOE integrals and hydrogen atom distances proofs the correct analysis. 相似文献
19.
Misaki Mitsuoka Dr. Daisuke Sakamaki Prof. Dr. Hideki Fujiwara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(62):14144-14151
A new tetrathiafulvalene (TTF) derivative is synthesized, which is substituted with two phenoxy radicals on one 1,3-dithiole ring, and may have either open-shell diradical or closed-shell extended-quinoidal ground states. X-ray single crystal analysis and NMR measurements prove that this molecule has a closed-shell extended quinoidal structure both in the solid state and in solution. DFT calculations show the donor–acceptor electronic properties of this molecule with a well-separated HOMO–LUMO distribution and a small HOMO–LUMO energy gap. Because of this donor–acceptor character, this molecule gives both the dication and the dianion species by electrochemical oxidation and reduction. Furthermore, during the redox process between the neutral and dication states, this molecule exhibits unique changes in the cyclic voltammogram upon repeating the cycles or varying the scan rate. The observed electrochemical behavior is explained by the conformational changes in the electrochemically generated species, thus indicating that this molecule is classified as a dynamic redox system. 相似文献
20.
Mélanie Bordeaux Dr. Anne Galarneau Dr. Jullien Drone 《Angewandte Chemie (International ed. in English)》2012,51(43):10712-10723
Selective catalysts for sustainable oxidation of alkanes are highly demanded because of the abundance of these molecules in the environment, the possibility to transform them into higher‐value compounds, such as chemicals or synthetic fuels, and the fact that, kinetically speaking, this is a difficult reaction. Numerous chemical and biological catalysts have been developed in the lasts decades for this purpose, rendering the overview over this field of chemistry difficult. After giving a definition of the ideal catalyst for alkane oxyfunctionalization, this review aims to present the catalysts available today that are closest to ideal. 相似文献