促进学生有机物性质认识能力发展的“醇类”教学研究

以"有机化学基础"选修模块中醇类及相关内容的教学设计为研究对象,探讨了醇类知识对于促进学生以有机物性质认识能力为核心的有机化学认识素养发展的功能和价值,从促进学生有机物性质认识能力发展的角度设计并实施了凸显"结构分析-性质预测"的探究活动为主的醇类教学,通过问卷调查和对学生的访谈对教学效果进行检测,并进行了基于学生不同认识基础的"醇类"教学效果的对比研究,探研先期所学习的结构与性质关系以及反应类型等知识对于学生有机物性质认识能力发展的积极影响。     

促进学生有机物认识方式发展的烃、卤代烃单元复习教学研究

在烃、卤代烃单元复习教学之前,探查了学生对有机物的认识方式和基础知识的掌握情况,进而将复习课的核心教学目标定位为"建立基于化学键的有机物认识方式,促进学生有机物认识方式的发展"。基于复习教学目标,设计了认识性任务、问题、活动及其具体的教学过程,通过设计2种任务类型实现同课异构。通过教学实践,分析教学效果,探讨促进学生有机物认识方式发展的有效教学策略。     

元素周期律复习教学中认识模型建构的有效策略

探查了元素周期律复习教学中认识模型构建的有效策略。从学生对于元素周期律的学后障碍点及相应的发展核心入手,在北京市选择了2所学生水平不同的学校分别进行了2课时的元素周期律复习教学。教学过程中基于学生认识发展的核心,选取了不同的模型构建组织策略,通过进阶式的教学任务对元素周期律的“位置-结构-性质”认识模型和物质性质的认识模型进行了构建。在问卷测查以及将本研究授课效果与常规授课进行对比后,证明并提炼了基于模型构建的元素周期律复习教学的有效策略。     

促进学生有机物性质认识能力发展的先行组织者的建构

以高中生有机物性质认识能力的构成为指导,基于对不同版本教材为学生认识有机物性质所搭建的先行组织者的内容与功能的分析,基于对北京市丰台区学生情况的分析,阐述了为促进学生有机物性质认识能力发展,建构认识域及认识角度和思路的策略及方法。     

促进学生认识发展的“微观结构与物质的多样性”单元教学设计

对已有的认识方式4要素的关系进行了修正,在分析了学生已有的物质结构基础知识和已有认识方式的基础上,阐述了“微观结构与物质的多样性”对学生认识方式可能产生的影响。分析了如何通过单元教学设计来实现这种影响,促进学生认识方式的发展,并给出了教学设计案例。     

电化学认识模型及其在高三原电池复习教学中的应用

综述了关于高中原电池教与学的已有研究,分析了电化学知识要求和学生电化学认识特点,从电化学的本体维度、认识维度和问题维度,构建并提出了高中电化学认识模型,并在高三原电池复习教学中进行了应用,针对分析型任务和设计型任务进行对比性教学实验。通过对学生电化学认识发展的前后测及其对比统计分析,并结合学生访谈对教学效果进行了检验,在此基础之上进一步分析和概括了基于电化学认识模型建构的原电池复习教学有效策略。     

立体化学教学中空间感观能力的培养

介绍了在有机物结构、有机反应机理和构象快速转换平衡的教学中培养学生构建空间感观的策略.教学实践表明,这些策略的实施具有较好的效果.     

新高考背景下高考化学试题分析与命题研究——水溶液主题

通过建立模型分析了近6年来的北京市高考试题。从试题水平来看,学生需要建立水溶液问题的基本认识角度和分析思路;从能力要求来看,部分试题实现了对关键能力的融合考查。在此基础上进行试题命制和施测,发现学生不能自主调用多个认识角度形成思路,提出了比较不同问题情境中的共同认识角度与建立“水溶液-平衡”二元分析模型的教学改进策略。     

发展高中生有机物化学性质核心概念理解的研究——“卤代烃”教学案例

在"卤代烃"的教学中,基于探查学生的迷思概念,采用在教师引导下进行实验探究的策略,发展高中生有机物化学性质核心概念的理解能力。主要介绍教学内容分析、核心概念分析、学生情况分析、教学目标、教学过程和教学效果评价等。     

素养导向的高中化学项目教学中教师有效行为研究——以“探秘神奇的医用胶”项目教学为例

以“探秘神奇的医用胶”为主题设计实施了素养导向的项目教学。从教师行为的角度,对本次项目教学的课堂录像编码分析,发现本次项目教学的3个关键过程、7种高频行为类型、7种高频和次高频问题类型。根据编码结果回顾课堂录像,分析讨论教师在项目教学中如何通过高频行为类型、高频和次高频问题类型帮助学生建立有机物和有机反应的认识角度和认识思路,促进学生化学学科核心素养的发展。     

A methodology for choosing parameters for ESR readout of alanine dosimeters for radiotherapy

Spectrometer settings for ESR readout of alanine dosimeters for radiotherapy have been investigated. Several ESR parameters were studied and determined. The main reason for this work is to choose the suitable parameters to increase signal-to-noise ratio and to reduce the uncertainty on ESR readout, which is one of the main components of uncertainty of alanine/ESR dosimetry system for radiotherapy. The new spectrometer settings have been applied for ESR readout of alanine dosimeters irradiated from 1 to 10 Gy. A higher signal-to-noise ratio has been achieved compared to our old spectrometer settings. The extended uncertainty (k=2) has been evaluated in the dose range 2–10 Gy (maximum uncertainty of 4.9% for 2 Gy, while minimum uncertainty of 1.4% for 10 Gy), which implies that the alanine/ESR dosimetry system can be applied to radiotherapy dose level that needs a global accuracy of 5%.     

Potential of FTIR spectroscopy for analysis of tears for diagnosis purposes

It has been widely reported that the tear film, which is crucially important as a protective barrier of the eye, undergoes biochemical changes as a result of a wide range of ocular pathology. This tends to suggest the possibility of early detection of ocular diseases on the basis of biochemical analysis of tears. However, studies of tears by conventional methods of biomolecular and biochemical analysis are often limited by methodological difficulties. Moreover, such analysis could not be applied in the clinic, where structural and morphological analyses by, mainly, slit-lamp biomicroscopy remains the recommended method. In this study, we assessed, for the first time, the potential of FTIR spectroscopy combined with advanced chemometric processing of spectral data for analysis of raw tears for diagnosis purposes. We first optimized sampling and spectral acquisition (tears collection method, tear sample volume, and preservation of the samples) for accurate spectral measurement. On the basis of the results, we focused our study on the possibility of discriminating tears from normal individuals from those of patients with different ocular pathologies, and showed that the most discriminating spectral range is that corresponding to variations of CH₂ and CH₃ of lipid aliphatic chains. We also report more subtle discrimination of tears from patients with keratoconus and those from patients with non-specific inflammatory ocular diseases, on the basis of variations in spectral ranges attributed notably to lipid and carbohydrate vibrations. Finally, we also succeeded in distinguishing tears from patients with early-stage and late-stage keratoconus on the basis of spectral features attributed to protein structure. Therefore, this study strongly suggests that FTIR spectral analysis of tears could be developed as a valuable and cost-saving tool for biochemical-based detection of ocular diseases, potentially before the appearance of the first morphological signs of diseases. Combined with supervised modelling methods and with use of a spectral data base acquired for representative patients, such a spectral approach could be a useful addition to current methods of clinical analysis for improvement of patient care.

Application of thermal analysis for investigations of polymer powders for coatings

Polypropylene coatings obtained by the fluidized bed method were investigated. It was proved that the application of thermal analysis methods for their characterization gave many useful data, as a consequence of the similar conditions of thermal measurements and plastics powder processing. Significant correlations were found between the thermal properties and the standard coating poperties.

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Zusammenfassung Durch Fluidisationsverfahren erhaltene Polypropylenbeschichtungen wurden untersucht. Es wurde festgestellt, daß infolge der ähnlichen Bedingungen von thermischen Messungen und Plastpulverisierungsverfahren die Anwendung von thermischen Untersuchungsmethoden zu deren Charakterisierung viele nützliche Angaben liefern. Es konnten eindeutige Beziehungen zwischen thermischen Eigenschaften und Standardbeschichtigungseigenschaften gefunden werden.

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Prospects for development of a technology for production of butene-1

Industrial technologies for production of butene-1 are described, including the most promising process for recovery of butene-1 of polymerization purity from C₄ fractions formed in pyrolysis and catalytic cracking of hydrocarbons. It is shown that this technology can be improved and suggested to use as a raw material the recycle butene fraction formed from these C₄ fractions upon isolation of 1,3-butadiene and isobutene. A technological scheme for recovery of butene-1 of polymerization purity is suggested.     

Preparation of PVA membrane for immobilization of GOD for glucose biosensor

A membrane was prepared using polyvinyl alcohol (PVA) with low and high degree of polymerization (DOP), acetone, benzoic acid (BA) and was cross-linked by UV treatment. Membrane composition was optimized on the basis of swelling index. Membrane prepared with 12% low DOP and 8% high DOP of PVA, 2% BA, dissolved in buffer containing 20% acetone and cross-linked with UV treatment exhibited lower swelling index. Fourier transform infrared (FTIR) study of the membranes showed appearance of a strong band at approximately 2337 cm(-1) when UV was used for cross-linking in the presence of benzoic acid. Scanning electron microscope (SEM) study revealed that membrane cross-linked with UV treatment was smoother. Glucose oxidase (GOD)-PVA membrane was associated with the dissolved oxygen (DO) probe for biosensor reading. Glucose was detected on the basis of depletion of oxygen, when immobilized GOD oxidizes glucose to gluconolactone. A wide detection range, 0.9-225 mg/dl was estimated from the linear range of calibration plot of biosensor reading. Membranes were reused for 32 reactions without significant loss of activity and stored for 30 days (approximately 90% activity) at 4 degrees C. Membranes were also used with real blood samples.     

New method for prefractionation of plasma for proteomic analysis

The depth of proteome analysis is severely limited in complex samples with a wide dynamic range of protein abundance such as plasma. Removal of high‐abundance proteins should reveal the signal of lower abundance plasma proteins. However, smaller proteins may be part of larger protein complexes and hence the removal of proteins involved in complexes with high‐abundance proteins such as albumin may inhibit the search for disease biomarkers. Prefractionation of a sample divides it into fractions of reduced complexity, allowing improved detection of lower abundance proteins. Using a prefractionation device, which employs Gradiflow? technology, we were able to separate small volume plasma samples into multiple fractions based on the molecular weight and/or charge. The resulting samples of reduced complexity were directly compatible with 2‐DE. The use of this prefractionation machine may therefore be useful in the hunt for disease biomarkers.     

Adhesives for assembly procedures for products of radioelectronic industry

A list of adhesive materials, sealants, and potting compounds used at the enterprise is given. The basic properties of these materials are discussed, and particular process procedures in which they are employed are described.     

Piperazine-based buffers for liposome coating of capillaries for electrophoresis

Anionic liposomes can be coated on fused-silica capillaries for electrophoresis in the presence of N-(hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) (HEPES) as background electrolyte (BGE) solution. In this work, the interaction of various compounds with zwitterionic and anionic phospholipid coatings was studied with HEPES at pH 7.4 as BGE solution. The chromatographic and electrophoretic behavior of three test sample solutions (anionic, cationic, and neutral) was investigated for evaluation of the phospholipid coatings. Our results show that hydrophobic interactions between analytes and the phospholipid coating are important for the migration of charged analytes. In addition, the performances of other piperazine-based buffers, i.e., N-(2-hydroxyethyl)piperazine-N'-(2-hydroxypropanesulfonic acid), piperazine-N,N'-bis(2-ethanesulfonic acid), and piperazine-N,N'-bis(hydroxypropane sulfonic acid), at pH 7.4, as liposome solvent and BGE solution were evaluated and compared with the performance of HEPES at pH 7.4. The anionic liposome solution comprised 80/20 mol% phosphatidylcholine/phosphatidylserine. A simple test solution was selected and the chromatographic and electrophoretic migration behavior of the analytes was evaluated. The results show that, in addition to HEPES, other piperazine-based buffers at pH 7.4 are suitable for coating of fused-silica capillaries with anionic liposomes.     

Prospects for the use of fluidized-bed devices for production of coatings

It is shown that, currently, the most effective grinding and dispersant equipment in the technology of coating production are fluidized-bed devices—devices in which grinding and dispersion of pigments and fillers occur via ferromagnetic bodies driven by an electromagnetic field.     

缓冲溶液pH计算公式的推导

酸碱缓冲溶液在分析化学中的应用是多方面的 ,因此酸碱缓冲溶液 ｐＨ的计算是分析化学中必不可少的一个内容。目前 ,高师院校的分析化学多采用华中师范大学等校编的《分析化学》(第 2版 ) ,笔者在几年的教学中 ,发现该教材在缓冲溶液 ｐＨ计算的公式推导中存在疏漏。为此 ,在比较其他教材中该章节的内容后 ,从酸碱平衡最本质的内容ＰＢＥ出发 ,提出一种新的缓冲溶液ｐＨ计算公式推导方法。1　华中师范大学版教材中的问题[1]　　以一元弱酸及其共轭碱体系进行讨论 ,设弱酸ＨＡ浓度为ｃａ,共轭碱ＮａＡ浓度为ｃｂ。将ＨＡ Ａ-体系以Ｈ2 Ｏ作媒…