基于机器人制样和激光诱导击穿光谱分析技术的选煤厂检测系统无人化

目前选煤厂煤质检测过程自动化程度低,采样与制样技术需要大量的人工参与。检测技术的落后直接影响数据的准确性从而对整个选煤厂生产过程控制与产品质量控制产生重要影响,直接关系选煤厂的经济效益。面对产业升级的需要,将先进的自动采制样技术引进煤炭生产经营企业是当务之急。机器人采制样系统包含:机械化采样与初制样技术、机器人精细化制样技术、煤炭快速检测技术、自动快速浮沉技术,为选煤厂提供了一种全自动采制检的新技术方案。     

制样方法对固体粉末X射线光电子能谱测试结果的影响

为了得到准确且分辨率高的X射线光电子能谱(XPS)数据,采用不同制样方法对不同类型的导电、不导电和混合粉末的测试结果进行了研究. 从图谱半峰宽、是否有荷电、真实性、制样效率和数据处理等方面阐述不同制样方法对测试结果的影响. 试验结果表明,对于导电和不导电粉末,粘取制样略优于铟片制样,其中使用碳导电胶带制样效果更好. 对于混合样品,Scotch双面胶带粘样后的测试结果优于其他3种制样方式. 此外,铟片制样可作为数据处理时荷电校正的参考方法.     

Miniaturized sample preparation combined with liquid phase separations

Miniaturized sample preparation methods designed as the sample pretreatment for liquid phase separations, such as liquid chromatography, capillary electrophoresis and capillary electrochromatography, have been reviewed especially for the on-line coupling of the sample preparation process and the separation process. The development of the desorption interfaces for the effective combining of the sample preparation and subsequent liquid phase separations is briefly described along with the applications of the combined analytical systems to the analysis of complex sample mixtures such as biological and environmental matrices. Novel use of fine polymeric filaments as the extraction medium for microscale liquid phase separation methods are investigated and a comparison is made with other sample preparation techniques. Polymer coating onto the fibrous material is also introduced to further develop microscale sample preparation methods with improved extraction performance. Several other microscale sample preparation methods having a potential compatibility to the liquid phase separations are also described for future applications of these techniques.     

标准气体的制备方法及配制技术

介绍标准气体的制备及杂质去除方法,包括单一组分纯气体的制备方法和混合气体的配制方法,5种常用气体的配制方法及特殊性质的标准气体的配制方法。     

Measurement uncertainty from physical sample preparation: estimation including systematic error

A methodology is proposed, which employs duplicated primary sampling and subsequent duplicated physical preparation coupled with duplicated chemical analyses. Sample preparation duplicates should be prepared under conditions that represent normal variability in routine laboratory practice. The proposed methodology requires duplicated chemical analysis on a minimum of two of the sample preparation duplicates. Data produced from the hierarchical design is treated with robust analysis of variance (ANOVA) to generate uncertainty estimates, as standard uncertainties ('u' expressed as standard deviation), for primary sampling (ssamp), physical sample preparation (sprep) and chemical analysis (sanal). The ANOVA results allow the contribution of the sample preparation process to the overall uncertainty to be assessed. This methodology has been applied for the first time to a case study of pesticide residues in retail strawberry samples. Duplicated sample preparation was performed under ambient conditions on two consecutive days. Multi-residue analysis (quantification by GC-MS) was undertaken for a range of incurred pesticide residues including those suspected of being susceptible to loss during sample preparation procedures. Sampling and analytical uncertainties dominated at low analyte concentrations. The sample preparation process contributed up to 20% to the total variability and had a relative uncertainty (Uprep%) of up to 66% (for bupirimate at 95% confidence). Estimates of systematic errors during physical sample preparation were also made using spike recovery experiments. Four options for the estimation of measurement uncertainty are discussed, which both include and exclude systematic error arising from sample preparation and chemical analysis. A holistic approach to the combination and subsequent expression of uncertainty is advised.     

纳米纤维素的制备

在纳米尺寸范围操控纤维素分子及其超分子聚集体,结构设计并组装出稳定的多重花样,由此创制出具有优异功能的新纳米精细化工品、新纳米材料,是纤维素科学的前沿领域和热点。为了研究当前制备纳米纤维素的现状和发展方向,简述了纳米纤维素化学基础,介绍了三类纳米纤维素：纳米纤维素晶体（晶须）、纳米纤维素复合物和纳米纤维素纤维,重点综述了纳米纤维素的五种制备方法：化学法制备纳米纤维素晶体和晶须、生物法制备细菌纤维素、物理法制备微纤化纳米纤维素、人工合成纳米纤维素和静电纺丝制备纤维素纤维,讨论了各种制备方法的优点和缺点,指出开展纳米纤维素超分子的可控结构设计、立体与位向选择性控制与制备、分子识别与位点识别等自组装过程机理、多尺度结构效应的形成机理等基础理论性研究是主要研究基础,新型的、绿色、低能耗、快速、高效的制备方法是纳米纤维素制备方法的发展方向。     

Main stages of gluing technology

The main stages of gluing technology—from surface preparation for gluing to control of the quality of adhesive joints—are considered. Methods of preparation for gluing of surfaces of polymer materials and metals are given. Recommendations for preparation and coating of adhesives are given. The main parameters of the adhesive curing and apparatus used are described.     

基于色谱-质谱联用的脂质分析样品前处理技术研究进展

脂质作为细胞膜和亚细胞膜的主要结构成分,在能量来源、细胞信号传导等多种生物学过程中发挥着重要作用。近年来,脂质分析受到越来越多的关注,其中色谱-质谱联用技术在脂质分析中占据主导地位。由于样品基质复杂,样品前处理有富集痕量物质和减少基质干扰的作用,成为脂质分析中的一个关键步骤。该文综述了近年来基于色谱-质谱联用技术的脂质分析中样品前处理技术的研究进展和应用,对各种样品前处理技术进行了阐述和总结。基于液相的萃取方法有液-液萃取和单一有机溶剂萃取。基于固相的萃取方法包括固相萃取和固相微萃取。场辅助萃取方法包括超临界流体萃取、加压流体萃取、微波辅助萃取和超声辅助萃取。此外,还介绍了在线联用样品前处理方法和用于活体分析的样品前处理方法。最后,对基于色谱-质谱联用的脂质分析样品前处理技术存在的问题及发展趋势进行了探讨。样品前处理技术的发展将提高脂质分析的灵敏度、选择性和分析速度。     

On-line sample preparation for high throughput reversed-phase LC/MS analysis of combinatorial chemistry libraries

An on-line sample preparation method utilizing a time-programmed autosampler is described for high throughput liquid chromatography/mass spectrometry (LC/MS). This approach is particularly helpful for the LC/MS analysis of samples which require solvents incompatible with HPLC in the sample preparation process. The on-line sample preparation approach minimizes a bottleneck in throughput and improves sample recovery under some circumstances.     

Rapid preparation of cellulose nanofibre sheet

Cellulose nanofibre sheet materials are of great interest in various applications because of their excellent properties, but are difficult to prepare rapidly and as large sheets. This paper describes a quick preparation procedure for preparing optically transparent, flat and smooth nanofibre sheets, which is much quicker than existing methods. Low permeability, optical transparency, high strength and high density show that nanofibres were well dispersed. The preparation time for the nanofibre sheet produced here was 10 min whereas the preparation times reported in literature is above 1 h. The decrease in sheet preparation time suggests that this method can be used for commercial applications.     

Nano-emulsions: New applications and optimization of their preparation

Nano-emulsions, as non-equilibrium systems, present characteristics and properties which depend not only on composition but also on the preparation method. Although interest in nano-emulsions was developed since about 20 years ago, mainly for nanoparticle preparation, it is in the last years that direct applications of nano-emulsions in consumer products are being developed, mainly in pharmacy and cosmetics. These recent applications have made that studies on optimization methods for nano-emulsion preparation be a requirement. This review is focused on the most recent literature on developments of nano-emulsions as final application products and on the optimization of their preparation.     

高纯橙皮素的制备及HPLC纯度分析

建立了一种基于反相硅胶纯化的高纯橙皮素制备方法,充分优化了上样量、流速及洗脱液极性等因素,采用红外光谱法和核磁共振对纯化后产物进行定性分析,高效液相色谱法检测纯化前后橙皮素的纯度,最终产物的纯度达99.87%。该方法快速简便、制备量大、分离效率高,每天制备效率可达到克级,为制备橙皮素标准物质提供了技术支撑。     

Colloids for Catalysts: A Concept for the Preparation of Superior Catalysts of Industrial Relevance

Compared to conventional preparation methods for supported heterogeneous catalysts, the use of colloidal nanoparticles (NPs) allows for a precise control over size, size distribution, and distribution/location of the NPs on the support. However, common colloidal syntheses have restrictions that limit their applicability for industrial catalyst preparation. We present a simple, surfactant‐free, and scalable preparation method for colloidal NPs to overcome these restrictions. We demonstrate how precious‐metal NPs are prepared in alkaline methanol, how the particle size can be tuned, and how supported catalysts are obtained. The potential of these colloids in the preparation of improved catalysts is demonstrated by two examples from heterogeneous catalysis and electrocatalysis.     

Synthesis and characterization of 2,6-bis-hydrazinopyridine, and its conversion to 2,6-bis-pyrazolylpyridines

2,6-Bis-hydrazinopyridine has been prepared and characterized for the first time. This material is useful for the preparation of a wide variety of 2,6-bis-pyrazolylpyridines. This approach represents the most efficient preparation to date of sterically crowded 2,6-bis-pyrazolylpyridines, and the only method for the preparation of pyrazolylpyridines containing unsymmetrically 3′,5′-disubstituted pyrazoles with the larger groups in the 5′ positions.     

Instant ligand libraries. Parallel synthesis of monodentate phosphoramidites and in situ screening in asymmetric hydrogenation

Chiral phosphoramidites have been identified as excellent ligands for various metal-catalyzed enantioselective transformations. Taking advantage of their easy preparation and modular nature, we designed a fully automated protocol for the parallel preparation of a library of 32 phosphoramidites and its screening in asymmetric hydrogenation of amino acid precursors. This initial study led to the discovery of a new ligand for the preparation of an enantiopure beta(3)-homoalanine precursor. [structure--see text]     

科学做好基础化学实验的细化准备

科学做好基础化学实验的细化准备,为实验教学提供更高效的服务,是实验室建设与管理内涵建设的内容之一。本文介绍了厦门大学化学国家级实验教学示范中心无机及化学分析实验教学准备工作的一些具体做法和经验,以期为高校基础化学实验的准备工作提供适用的参考与借鉴。     

合成丙交酯的催化剂研究进展

丙交酯作为合成聚乳酸的重要中间体,它的制备效率是影响两步法聚合高分子量PLA的关键因素。寻找高效催化剂是其中一个重要的解决方案,本文就与日俱增交酯合成过程中不同催化剂体系的选择进行了综述,未来的工作应放在催化剂和制备效率上。     

Optimization and characterization of a sulfate based electrodeposition method for alpha-spectrometry of neptunium and curium

The parameters for a sulfate based electrodeposition method were optimized for the preparation of Cm and Np alpha-spectrometry sources. Alpha-spectrometry requires the preparation of essentially massless sources to eliminate self-absorption of alpha-particles, which can cause degraded alpha-spectra. A variety of methods for the electrodeposition of actinides have been reported in the literature, many of which require long deposition times and lack reproducibility. A previously reported sulfate based method has been evaluated for the preparation of Np and Cm sources. High yields were achieved and source preparation took 90 minutes or less. The effects of electrodeposition time and pH of the depositing solution were evaluated for each element. Typical resolution (FWHM) for sources prepared by this method is 50 keV or less with recoveries approaching 100%.     

Alkynes and Nitrogen Compounds: Useful Substrates for the Synthesis of Pyrazoles

The easy preparation and functionalization of pyrazoles associated with their innumerable biological properties have made this class of N-heterocycles very attractive for the development of new synthetic routes and applications. The cyclization reactions of alkynes and nitrogen compounds represent a powerful tool for the preparation of pyrazoles. This Review covers the recent advances in the preparation of pyrazoles by reacting alkynes and nitrogen compounds under transition-metal-catalyzed or metal-free conditions.     

Synthesis of polyazamacrocyclic compounds via modified Richman-Atkins cyclization of beta-trimethylsilylethanesulfonamides

The Richman-Atkins cyclization remains one of the most widely used methods for the preparation of macrocyclic polyamines. The use of beta-trimethylsilylethanesulfonamides (SES-sulfonamides) for the preparation of polyazamacrocyclic compounds is described. This expands existing Richman-Atkins sulfonamide macrocyclization methodology, and it successfully enables preparation of labile polyaza[n](1,4)naphthalenophanes and polyaza[n](9,10)anthracenophanes, not previously available in appreciable quantities.