食品中主要霉菌毒素分析方法的研究进展

食品中霉菌毒素的检测面临基质复杂、污染浓度水平低的困扰,研发选择性高、富集能力强的样品前处理方法和高灵敏的分析方法对于提升食品中霉菌毒素的检测能力、保障食品安全具有重要意义。该文综述了近年来食品中霉菌毒素分析方法的研究进展,并对其发展方向作总结和展望。     

Assessment of the Strength of Energetic Compounds Through the Trauzl Lead Block Expansions Using Their Molecular Structures

The strength of energetic materials can be expressed as the expansion of the cavity of a standard lead block through explosion of the sample. A new method is introduced for prediction of the Trauzl lead block expansions for some of the important classes of pure and mixture of energetic compounds, with the general formula of C_aH_bN_cO_d. This model needs only the molecular structure of the energetic materials without using the detonation characteristics of different explosives. The model uses the ratios of the number of carbon to oxygen (a/d) and hydrogen to oxygen atoms (b/d). The effects of intra‐ and intermolecular interactions are applied to the model by assignment of some correcting parameters upon considering certain molecular fragments. This model gives more reliable results with respect to three of the best available methods.     

Synergistic relationships between Analytical Chemistry and written standards

This paper describes the mutual impact of Analytical Chemistry and several international written standards (norms and guides) related to knowledge management (CEN-CWA 14924:2004), social responsibility (ISO 26000:2010), management of occupational health and safety (OHSAS 18001/2), environmental management (ISO 14001:2004), quality management systems (ISO 9001:2008) and requirements of the competence of testing and calibration laboratories (ISO 17025:2004). The intensity of this impact, based on a two-way influence, is quite different depending on the standard considered. In any case, a new and fruitful approach to Analytical Chemistry based on these relationships can be derived.     

Radioactivity distribution at MAFF

A detailed account on the distribution of radioactive nuclei in the vacuum system of the planned Munich Accelerator for Fission Fragments (MAFF) located at the FRM-II research reactor is presented. Tools used for the simulation of spacial and temporal distribution of radionuclides are explained. The latter allows for a detailed activity budget as well as estimates for the mass-separated ion yields at MAFF. Additionally, a concept to reduce the activity release from the MAFF slit system due to surface sputtering is presented. It is shown, that the use of low-density carbon foam, as a surface coating, reduces sputtering by orders of magnitude.     

Magnetically programmable shunt valve: MRI at 3-Tesla

A magnetically programmable cerebrospinal fluid (CSF) shunt valve (Codman Hakim Programmable Valve, Codman, a Johnson & Johnson Company, Raynham, MA) was assessed for magnetic field interactions, heating, artifacts and functional changes at 3-Tesla. The programmable valve showed minor magnetic field interactions and heating (+0.4 degrees C). Artifacts were relatively large in relation to the size and shape of this implant and, as such, may create a problem if the area of interest is in proximity to this implant. While multiple exposures and various magnetic resonance imaging (MRI) conditions at 3-Tesla changed the settings of some valves (i.e., reprogramming was needed), the function of the programmable valve was not permanently affected. Therefore, this magnetically programmable CSF shunt valve is acceptable for a patient undergoing MRI at 3-Tesla or less when specific safety guidelines are followed, including resetting the valve, as needed.     

A model for droplet entrainment in heated annular flow

The ability to accurately predict droplet entrainment in annular two-phase flow is required to effectively calculate the interfacial mass, momentum, and energy transfer, which characterizes nuclear reactor safety, system design, analysis, and performance. Most annular flow entrainment models in the open literature are formulated in terms of dimensionless groups, which do not directly account for interfacial instabilities. However, many researchers agree that there is a clear presence of interfacial instability phenomena having a direct impact on droplet entrainment. The present study proposes a model for droplet entrainment, based on the underlying physics of droplet entrainment from upward co-current annular film flow that is characteristic to light water reactor safety analysis. The model is developed based on a force balance and stability analysis that can be implemented into a transient three-field (continuous liquid, droplet, and vapor) two-phase heat transfer and fluid flow systems analysis computer code.     

Syntheses of novel delocalized cations and fluorinated anions,new fluorinated solvents and additives for lithium ion batteries

To improve the properties of rechargeable lithium ion batteries, like conductivity, SEI-formation, thermal and electrochemical stability, low and high temperature performance and safety new electrolyte salts, novel solvents (co-solvents) and additives have been synthesized. All new anions, solvents and additives contain fluorine proving the importance of this element for the electrolyte system. Tetrafluoroborates having bulky delocalized nitrogen-, phosphorus and sulfur-centered counter-cations containing tetramethylguanidyl substituents, like [(Me₂N)₂CNC(NMe₂)₂]⁺, have been prepared to improve the conductivity in polymer electrolytes. The hitherto unknown lithium sulfonate, MeOCF₂CF₂SO₃Li, has been successfully synthesized along with further analogs, and also MeOCF₂CF(CF₃)SO₃Li was obtained, both from precursors, FO₂SCF₂C(O)F or FO₂SCF(CF₃)C(O)F accessible by ring opening reactions from the respective sultones. For the lithium salt CF₃OCF(CF₃)SO₃Li, a new simple synthetic pathway was found where CF₃OCFCF₂ and SO₂F₂ were used as precursors. Novel possible redox shuttles, namely (CF₃)₅C₆OLi and fluorinated pyridine-N-oxides have been prepared. A neutral cyclic carben-PF₅ adduct turned out to be a very effective overcharge protection additive. The family of cyclic and acyclic carbonates playing a key-role as electrolyte solvents in lithium ion batteries could be extended by derivatives of 1,1,1,4,4,4-hexafluorobutandiol. Reaction products from perfluoropropene oxide and alcohols, ROC(F)CF₃C(O)OR (R = CH₂CF₃, CH₂CH₂, CH(CF₃)₂) were obtained according to new optimized methods. New cyclic sulfonamides synthesized from FO₂SCF₂C(O)F and FO₂SCF(CF₃)C(O)F could be successfully identified as versatile electrolyte additives.     

基于RAMP安全原则的有机化学实验安全教育探索

安全教育是实验教学中的一个重要内容,本文立足RAMP安全原则,编制有机化学实验安全讲义,将安全教育有效整合到有机化学实验教学方案中,锻炼学生正确识别评估教学实验项目中的具体危险、合理减控风险及应急处置能力,有利于提高学生的安全意识和防控能力,加强实验教学全过程管理,并有效保障了实验室安全。     

无机钠离子电池固体电解质研究进展

地球上钠资源储量丰富、成本低廉,使得钠电池吸引了越来越多研究者的关注。传统的基于有机溶剂电解液体系的钠电池在安全方面存在不足。固态钠离子电池能够有效解决安全的问题,增加电池的安全性能。固态钠离子电池是一种很有前景的储能方式。钠离子固体电解质主要有Na-β-Al_2O_3、钠超离子导体(NASICON)、硫化物、聚合物以及硼氢化物这几类。无机固体电解质相对于聚合物固体电解质,离子电导率有优势。本文总结了三种常见的无机钠离子固体电解质:Na-β-Al_2O_3、NASICON、硫化物的研究进展,从离子电导率和界面稳定性等方面阐述了近年来的发展。