电动态平衡技术在研究单颗粒煤燃烧中的应用

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。     

粘度法对可溶解的聚氨酯交联大分子的溶液行为的研究

通过体积稀释法测定可溶性交联大分子溶液的特性粘数随交联度、浓度和时间的变化,发现聚氨酯可溶性交联大分子在溶液中出现与线型和支化型高分子溶液不一样的粘度行为.本文根据聚氨酯的特殊的结构对这些异常现象进行了解释.     

Measurement of Antioxidant Capacity of Meat and Meat Products: Methods and Applications

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.     

Nanoformulation of Lipophilic Osmium Photosensitizers in Liposomes and Micelles as a General Strategy for Improving Reproducibility and Reducing Quenching†

Nanoformulation of an osmium photosensitizer within liposomes and micelles is used to improve the water-solubility of this highly lipophilic molecule. This highlight report describes a recent paper by Cameron, Obaid and McFarland on this topic and discusses the context for this report. Nanoformulation has been explored as a strategy before, but this represents the first usage of this strategy with highly potent metal-based photosensitizers having phototherapeutic indices (PIs) in excess of 10⁴. The nanoformulation strategy is effective due to reducing aggregation and self-quenching of the photosensitizer molecules.     

Geometry and models in chemistry

Madame Curie was awarded her second Nobel Prize in 1911 and on this occasion it was in chemistry. Honoring the centennial of this event, the world celebrates chemistry in 2011. Chemistry serves the world every minute every year and the world reciprocates with paying attention to this often cursed but uniquely useful science during this particular year.     

Marie Sklodowska Curie and the Year of Chemistry

Madame Curie was awarded her second Nobel Prize in 1911 and on this occasion it was in chemistry. Honoring the centennial of this event, the world celebrates chemistry in 2011. Chemistry serves the world every minute every year and the world reciprocates with paying attention to this often cursed but uniquely useful science during this particular year.     

毛细管电泳-柱端电化学检测池的设计

在射壁式检测器的基规上,设计了一种用于毛细管电泳-电化学检测装置的检测池,巧妙地利用因表面张力现象而留驻波滴曲面的放大作用,直接调整毛细管与电极之间的相对位置,无需显微镜-微调节器装置,具有空间体积小,操作更简便的优点。     

扭辫分析法对糠醛聚合反应机理的研究

中村仪郎等对经酸催化而得的糠醛树脂通过红外和紫外光谱进行了结构分析。     

Insights Into f-element Coordination Chemistry in TALSPEAK Systems

Thermodynamic data from the literature properly predict lanthanide–actinide separation factors in the TALSPEAK process, but fail to predict the observed steep acid dependence that is seen when the pH is raised above 3. In this work, features of lanthanide coordination chemistry and solute partitioning in TALSPEAK are examined to improve understanding of the fundamental chemistry that controls this process and to explain this anomaly. To accomplish this, a variety of spectroscopic techniques have been applied to the task. In addition, since the issue with TALSPEAK appears to lie in part in the definition of thermodynamic equilibria, complementary studies have been conducted elucidating fresh estimates of selected thermodynamic parameters of relevance to this system. To extend the utility of this investigation, some of these studies have examined the properties of substitute reagents within the general framework of TALSPEAK and TALSPEAK-like systems. In this report, observations from NMR, ESI-MS, and optical spectroscopic studies of lanthanide complexes are combined with thermodynamic modeling to provide fresh insights into lanthanide-actinide separations systems based on aqueous complexing agents.     

Should non-significant bias be included in the uncertainty budget?

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     

二甲戊乐灵的GC-MS检验

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)。     

Metal ion directed self-assembly of sensors for ions, molecules and biomolecules

Recent years have seen a surge of interest in the metal-ion directed construction of discrete molecular assemblies. Once the versatility of this approach for the construction of hitherto inaccessible molecular architectures was demonstrated, work towards fully functional systems rapidly developed. Since these architectures have a wide range of possible applications, this perspective review will focus on one important aspect of this research: the construction of hosts with optical or electrochemical sensing outputs. As this overview will illustrate, research in this area is now producing working examples of sensors for variety of ionic, molecular, and biomolecular guests.     

Microcolumn Liquid Chromatography Combined with Computer-Assisted Retention Prediction System for Polycyclic Aromatic Hydrocarbons in Extract from Diesel Particulate Matter

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.     

Shear modulus of single wood pulp fibers from torsion tests

Cellulose - The shear modulus of pulp fibers is difficult to measure and only very little literature is available on this topic. In this work we are introducing a method to measure this fiber...     

Effect of arginine on stability of GST-ZNF191（243-368）

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.     

HMBC‐ und NOESY‐NMR‐Spektroskopie

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.     

超临界流体技术在化学研究中的应用

对超临界流体技术的应用和研究进行了综述。     

A novel particle separation method based on induced‐charge electro‐osmotic flow and polarizability of dielectric particles

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.     

ABEEM-σπ模型在典型Diels-Alder反应立体选择性上的应用

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.     

Angular Averaged Profiling of the Radial Electric Field in Compensated FTICR Cells

A recent publication from this laboratory reported a theoretical analysis comparing approaches for creating harmonic ICR cells. We considered two examples of static segmented cells--namely, a seven segment cell developed in this laboratory and one described by Rempel et al., along with a recently described dynamically harmonized cell by Boldin and Nikolaev. This conceptual design for a dynamically harmonized cell has now been reduced to practice and first experimental results obtained with this cell were recently reported in this journal; this publication reported details of cell construction and described its performance in a 7 tesla Fourier transform mass spectrometer. We describe the extension of theoretical analysis creating harmonic ICR cells to include angular-averaged radial electric field calculations and a discussion of the influence of trapping plates.