含芴共轭高分子的合成、表征及性能研究——推荐一个高分子化学综合实验

推荐了一个高分子化学综合实验——含芴共轭高分子的合成、表征及性能研究。实验内容包括利用Sonogashira偶联反应合成共轭高分子,采用核磁共振和红外光谱等检测手段对其结构进行表征,并利用紫外-可见光谱、荧光和热重分析对其性能进行研究。本实验结合了高分子化学和聚合物仪器分析与表征的知识点,建议纳入高分子专业高年级综合实验课程。     

气相色谱专家系统中柱系统的推荐

本文给出气相色谱专家系统中柱系统推荐软件的总体结构和设计及一个运用所研制的软件进行咨询的例子。用户只要回答与样品中组分结构有关的几个关键问题,软件即可对样品可否采用气相色谱法进行判断和对气相色谱柱系统进行推荐。从初步使用和验证来看,本系统是成功的。     

BODIPY基荧光探针的合成、表征及对铜离子的检测——推荐一个大学综合化学实验

介绍了一个大学综合化学实验——BODIPY基荧光探针的合成、表征及对铜离子的检测。该实验是一个科研转化的大学生综合化学实验,内容包括3,5-二氯BODIY的合成、BODIPY基荧光探针分子的合成,以及利用紫外-可见分光光度计和荧光光谱仪检测目标分子对金属离子的响应性。通过本实验,使学生了解BODIPY基荧光传感器这一科研前沿领域,激发学生对科学研究的兴趣,培养学生的科研探究能力。本实验综合了有机化学、仪器分析和应用波谱学知识点的学习,培养学生的实验操作技能,提升学生的综合及创新能力,建议纳入高年级综合化学实验课程。     

二次生长法NaA沸石分子筛膜的合成与表征——推荐一个研究型综合实验

介绍一个研究型综合实验——二次生长法NaA沸石分子筛膜的合成与表征。实验预先利用热浸渍法在α-Al_2O_3多孔载体管外表面引入NaA沸石分子筛晶种,再通过二次生长法合成NaA沸石分子筛膜。用扫描电子显微镜和X射线衍射仪表征载体管和NaA沸石分子筛及膜的形貌和结构,并利用渗透蒸发乙醇脱水膜分离装置测试膜的分离性能。通过本实验使学生了解膜分离技术这一科学前沿领域,激发学生对科学研究的兴趣,培养学生的科研探究能力。本实验涵盖合成、表征及性能测试,知识要点多、学科覆盖面广,有利于提升学生的实践操作能力、创新意识和综合运用知识的能力。     

大学化学综合实验:Fe/Fe3O4磁性材料的合成、结构性质与磁性能的测定*

推荐一个大学化学综合实验: Fe/Fe3O4磁性材料的合成、结构性质与磁性能的测定,该实验涉及材料的合成、结构表征和磁性能的测定。通过该实验可以使学生掌握一些大型仪器的基本原理和基本操作,掌握材料合成的方法、材料结构及形貌的表征手段以及磁滞曲线的测定方法。使学生在掌握材料研究的基础理论和基本实验技能的同时,培养学生独力实验能力和创新意识,尤其是培养他们综合运用知识的能力。进一步缩短教学与科研的距离。     

YVO4:Eu发光材料的合成、结构与荧光性——推荐一个大学综合实验

This comprehensive experiment is recommended for the synthesis, structure and fluorescence properties of YVO₄:Eu photoluminescent materials. The main purpose of this experiment is to introduce the research of fluorescent materials, including the synthesis of materials, structure characterization and fluorescence measurement. Students can master the basic principle and operation of instruments, the method for material synthesis, and luminescence properties of the materials. While mastering the basic theory and the basic experimental skills, the experimental ability and creative consciousness, especially their ability to use knowledge comprehensively, can be cultivated and improved. The distance between teaching and scientific research is shortened.     

新型电控荧光聚合物的合成与性能研究——推荐一个综合化学实验

介绍一个研究探索型大学化学综合性实验——新型电控荧光聚合物的合成与性能研究。内容包括电控荧光聚合物的合成及电控荧光性能的相关测试。通过本实验的实践,使学生在掌握基础理论和基本实验技能的同时,提高独立实验能力和创新意识。本实验的开展还可以使学生接触到学科的前沿领域,激发学生对科学研究的兴趣,培养学生的科研探究能力。     

Computer-assisted learning using a dialogue system for virtual teacher-student communication

Over the past decade, computer-assisted learning in the field of chemistry has given rise to a large number of systems that approach this objective from different viewpoints: static courses aimed at specific concepts, tutorial systems, 2D and 3D virtual environments, and so on. Correct structuring and representation of the knowledge to be taught, the building of a suitable student interface, and the adaptation of the learning process to the knowledge of the student are but a few of the challenges to be faced in the development of efficient computer-assisted learning systems. The present study tackles the use of computerized dialogue systems as a viable alternative for the simulation of teacher-student interaction and proposes an ontology for the characterization of such interaction, employing the object-oriented paradigm in the modeling of both the knowledge to be taught and the actual level of the student. The proposed solution is based on the representation of the knowledge to be taught through a network of multiconnected knowledge frames (chunks), where each chunk may be specialized in more specific frames (prerequisites and subobjectives), contain associated explanations of varying complexity and with a range of explanatory models, and be associated with one or a set of possible questions the student might ask; to this end, a constantly evolving knowledge model is maintained throughout the explanatory process. Based on the proposed model, Java was used to develop and manage an explanatory system that could be used in any type of teaching system based on student-dominated dialogues. Here, the system has been applied to the teaching of chemistry laboratory practice by its integration into the Virtual Chemistry Laboratory (VCL), a system designed by the authors to simulate chemistry techniques in a virtual 3D world.     

9-(4-溴丁基)-9H-咔唑的相转移催化合成、表征及室温磷光性能研究——推荐一个大学化学综合实验

推荐了一个大学化学综合实验"9-(4-溴丁基)-9H-咔唑的相转移催化合成、表征及室温磷光性能研究"。实验利用相转移催化合成9-(4-溴丁基)-9H-咔唑分子,采用核磁共振、高分辨质谱和红外光谱对其分子结构进行表征,并利用紫外-可见吸收光谱、稳态/瞬态荧光光谱和密度泛函(DFT)理论计算对其室温磷光性能进行研究。本综合实验涵盖了有机化学、分析化学、物理化学、仪器分析以及理论化学的知识点,建议纳入化学专业高年级综合实验课程。     

Analogs of tetrahydrofolic acid. XXXIX . selective bromoacylation of polyfunctional molecules for synthesis of active-site-directed irreversible enzyme inhibitors

A number of methods for selective bromoacylation of side-chain amino groups on 2-amino-4-pyrimidinols or 2,4,6-triaminopyrimidines have been developed for these extremely sensitive products. The choice of method depends upon whether (a) the aminopyrimidine is a stronger base than the amine to be bromoacylated, (b) as weak a base as the amine to be bromoacylated but the amine is more reactive, (c) the amine group to be bromoacylated is a strong aliphatic amine. In case (a) the aminopyrimidine can be protonated to protect it from acylation with an anhydride; in case (b), the reaction with an anhydride is controlled by temperature, stoichiometry, and time of reaction; in case (c), the reaction is selectively controlled by use of the less reactive p-nitrophenyl esters. Other difficulties were solved such as (a) proper characterization of the products when combustion analyses were unsatisfactory due to polymerization; in these cases a combination of thin layer chromatography, color reactions, and derivatization were employed; and (b) insolubility leading to overreaction on the aminopyrimidine which was solved with partial aqueous systems.     

Applications of imaged capillary isoelectric focussing technique in development of biopharmaceutical glycoprotein-based products

CE-based methods have increasingly been applied to the analysis of a variety of different type proteins. One of those techniques is imaged capillary isoelectric focusing (icIEF), a method that has been used extensively in the field of protein-based drug development as a tool for product identification, stability monitoring, and characterization. It offers many advantages over the traditional labor-intensive IEF slab gel method and even standard cIEF with on-line detection technologies with regard to method development, reproducibility, robustness, and speed. Here, specific examples are provided for biopharmaceutical glycoprotein products such as mAbs, erythropoietin (EPO), and recombinant Fc-fusion proteins, though the technique can be adapted for many other therapeutic proteins. Applications of iCIEF using a Convergent Bioscience instrument (Toronto, Canada) with whole-field imaging technology are presented and discussed. These include a quick method to establish an identity test for many protein-based products, product release, and stability evaluation of glycoproteins with respect to charge heterogeneity under accelerated temperature stress, different pH conditions, and in different formulations. Finally, characterization of glycoproteins using this iCIEF technology is discussed with respect to biosimilar development, clone selection, and antigen binding. The data presented provide a "taste' of what icIEF method can do to support the development of biopharmaceutical glycoprotein products from early clone screening for better product candidates to characterization of the final commercial products.     

Dielectric spectroscopy of thixotropic dispersions

The full characterization of a dispersion requires measurement of the degree of dispersion and knowledge of the type of structuring assumed by the dispersed particles. Dielectric spectroscopy in the low frequency range is a promising experimental approach to this problem.     

Characterization of Radioactive Hazardous Waste

The characterization of radioactive hazardous waste, also known as transuranic "mixed waste" has to be completed before it can be classified for proper treatment (incinerator, mechanical compaction or thermal treatment), packing, and transport. The characterization of the TRU mixed waste is not only complex process but rather an expensive undertaking. The process knowledge is the basic foundation of characterization. It is the documented knowledge of processes and materials that generated the waste. The transuranic waste Quality Assurance Program Plan (QAPP) defines the Data Quality Objectives (DQO's) and provides the scope of analytical parameters and methods required to accurately characterize the radioactive mixed waste. Based on the historical data and process knowledge a sampling and analysis plan can be developed to characterize the radioactive hazardous waste. Based on the characterization, an assessment of the regulatory status can be made before the waste could be accepted for disposal at the WIPP facility. The Waste Acceptance Criteria (WAC) developed by WIPP defines the parameters for receiving and final disposal of the TRU waste. The sets of criteria, such as: heat generated, fissile gram equivalent (FGE), plutonium-equivalent (PE) curies, and specifications of a dose rate have to be met before the waste is accepted for deep geological disposal. The characterization of radioactive waste becomes even more complex due to the presence of iron base metals/alloys, aluminum base metals/alloys, organic, chelating agents that are mixed with plastic, rubber, cellulose, soils and cement. Some of the modern characterization technologies that are under development and currently used for TRU mixed wastes are: nondestructive examination, nondestructive assay, headspace gas analysis, and drum coring for Resources Conservation Recovery Act (RCRA) sampling.     

Analysis of ceramides in cosmetics by reversed-phase liquid chromatography/electrospray ionization mass spectrometry with collision-induced dissociation

A rapid, sensitive and selective method involving reversed-phase liquid chromatography (LC) with electrospray ionization (ESI) mass spectrometry (MS) was employed for determination of commercial ceramides in cosmetics for quality control of the product formulation. Using this LC/ESI-MS technique, simultaneous separation and characterization of ceramides and an impurity substance were possible. Informative fragmentation patterns were obtained by employing LC/ESI-MS in both positive and negative ionization modes to identify the structures of both sphingoid base and N-acyl chains of ceramides, and also of an impurity. The combination of positive and negative mass spectra can be used for unambiguous confirmation of ceramides and for characterization of unknown species. In-source collision-induced fragmentation resulted in characteristic product anions for the ceramides containing a phytosphingosine moiety at m/z 267, 255 and 225, and for those with a sphingosine moiety at m/z 263 and 237, regardless of the length of the fatty acyl chains. The detection limit was about 0.5 pmol in selected-ion monitoring mode. Quantification using internal standards showed good linearity and a relative standard deviation of 4%. These ceramides were more sensitively detected in positive than in negative ion mode.     

一种金属有机框架纳米材料的制备及其染料吸附性能研究——推荐一个研究型综合化学实验

介绍一个从合成、表征到性能研究的完整研究型综合实验。合成路线巧妙,制备出了文献报道的尺寸最小的纳米金属有机框架。引入纳米材料研究基本表征手段和吸附动力学研究,通过实验教学展示材料研究方法,拓展学生知识面。通过对实验条件的设计,激发学生探索精神、培养学生创新意识、训练学生化学思维。     

K2GeF6:Mn荧光粉的化学共沉淀合成、结构测定与发光性能研究——介绍一个研究型综合实验

介绍一个大学化学研究型综合实验——K2GeF6:Mn荧光粉的化学共沉淀合成、结构测定与发光性能研究。本实验结合氧化还原与化学共沉淀法制备K2GeF6:Mn荧光粉,借助XRD和SEM对粉体进行结构表征,并利用荧光光谱仪测试分析其发光性能,探究激活剂含量和反应温度对粉体结构与性能的影响,获得可应用于商业白光LED的红色荧光粉。通过该实验的设计与实施,使学生在掌握基本实验技能的同时,能够结合基础理论知识解释实验原理、分析实验现象,并进一步提升学生的科学研究思维和综合运用知识的能力。     

Treatment of soy bean process water using hybrid processes

The soy bean process water that is a by-product of soy processing technology can be utilized with a hybrid separation system recommended and investigated in this work. The aims of the soy bean water processing are to i.) concentrate the valuable components of the soy process water and ii.) reuse its water content. Two hybrid separation systems are considered and investigated: ultrafiltration followed by nanofiltration and centrifugal separation followed by nanofiltration. These hybrid separation systems are new in the area of their current application. Experiments verify that centrifugal separation is a more appropriate pre-treatment method for the removal of suspended solids and for the preservation of the sucrose content of the soy bean process water than ultrafiltration. Total sucrose can be rejected by nanofiltration membrane forming a sugar-rich retentate that contains other valuable components, too. Both tested hybrid processes result in clear and reusable permeates with low chemical oxygen demand that can be recycled to the production process reducing its water consumption and improving its sustainability. The recommended new hybrid separation system, centrifugal separation followed by nanofiltration, proves to be successful in this area of the biochemical industry.     

碳布负载氢氧化镍电极材料的合成及其电容性能分析——推荐一个综合化学实验

作为超级电容器的电极材料,Ni(OH)₂具有理论比电容高、来源丰富、环境友好等优点,但较低的电导率影响了其实际性能。解决该问题的一种有效方法是在碳布导电基底上原位生长Ni(OH)₂薄膜。以此为基础设计综合化学实验,通过Ni(OH)₂/碳布薄膜电极的制备、表征及电化学性能测试,使学生进一步理解化学平衡原理在材料合成中的应用,了解材料的基本表征方法,掌握循环伏安法、恒流充放电法等电化学分析方法在实际测试中的运用与解析,从而达到巩固电化学理论知识、培养学生的实验技能、提高学生综合实验能力的目的。本实验的开展还可以帮助学生了解储能领域的科技前沿,激发学生的科研兴趣,培养学生的科研创新意识,适合在大学化学实验中推广应用。     

Rapeseed oil methyl ester pyrolysis: on-line product analysis using comprehensive two-dimensional gas chromatography

Thermochemical conversion processes play a crucial role in all routes from fossil and renewable resources to base chemicals, fuels and energy. Hence, a fundamental understanding of these chemical processes can help to resolve the upcoming challenges of our society. A bench scale pyrolysis set-up has been used to study the thermochemical conversion of rapeseed oil methyl ester (RME), i.e. a mixture of fatty acid methyl esters. A GC×GC, equipped with both a flame ionization detector (FID) and a time-of-flight mass spectrometer (TOF-MS), allows quantitative and qualitative characterization of the reactor feed and product. Analysis of the latter is accomplished using a dedicated high temperature on-line sampling system. Temperature programmed analysis, starting at -40°C, permits effluent characterization from methane up to lignoceric acid methyl ester (C(25)H(50)O(2)), in a single run of the GC×GC. The latter combines a 100% dimethylpolysiloxane primary column with a 50% phenyl polysilphenylene-siloxane secondary column. Modulation is started when the oven temperature reaches 40°C, thus dividing the chromatogram in a conventional 1D and a comprehensive 2D part. The proposed quantification approach allows to combine the quantitative GC×GC analysis with 2 other on-line 1D GC analyses, resulting in a complete and detailed product composition including the measurement of CO, CO(2), formaldehyde and water. The GC×GC reveals that the product stream contains a huge variety of valuable products, such as linear alpha olefins, unsaturated esters and aromatics, that could not have been identified and quantified accurately with conventional 1D GC because of peak overlap.