化学学习中“电解质”概念相异构想的跨年级研究

运用自编的二段式诊断测验,对10到12年级的529名中学生进行了“电解质”概念相异构想的问卷测查。对测查数据运用Rasch模型进行分析,结果显示不同年级中学生有关“电解质“的相异构想存在着差异。依据SOLO分类标准对中学生“电解质”的相异构想进行了分类,并借助课堂观察和访谈对不同年级中学生“电解质”相异构想的来源进行了分析。     

高三学生水溶液中离子平衡相异构想的调查

通过调查问卷和访谈方法,对高三53名学生关于“水溶液中的离子平衡”的相异构想进行调查研究,探查学生头脑中存在的相异构想,分析产生的原因,并以建构主义学习理论为指导,提出了转变相异构想的几点建议。     

中学生“原子结构”相异构想的认知成因分析及转变策略

物质结构内容的抽象性导致学生产生大量的相异构想,影响着学生对化学概念的学习和深刻理解。通过整合国内外相关研究结果,从思维的视角分析了中学生“原子结构”相异构想产生的原因,并提出转变学生相异构想、促进概念理解的教学策略。     

国内外化学相异构想研究的进展与启示*

国内外有关化学学科的相异构想研究主要包括对学生相异构想进行诊断及其原因分析,以及开发有效的教学模式或策略对学生相异构想进行概念转变。通过对国内外相关研究现状的分析,为相异构想的后续研究提供思路。     

转变初中生化学前概念中相异构想的教学策略

笔者在初中生化学前概念中相异构想成因的前期研究基础上,分析了影响学生相异构想转变的因素,并结合前人研究成果,从引发学生认知冲突、促进学生认知顺应、激发学习兴趣、促进学习主动调控等角度,初步提出了促进学生相异构想转变的教学策略.     

初中化学核心概念相异构想调查研究——以“酸、碱、盐”为例

采用自编的二段式多项选择诊断测验为研究工具,对55名初三学生“酸、碱、盐”核心概念的相异构想进行调查研究,诊断了学生头脑中存在的相异构想并探析了产生这些相异构想的成因和主要来源,为中学化学教师进行概念转变教学及相关研究提供一定的依据和思路。     

日常生活概念"平均"对科学概念"8电子稳定结构"学习的影响 --关于高一学生"8电子稳定结构"化学概念相异构想的研究

通过“游戏”和“访谈”方法,对高一学生“8电子稳定结构”化学概念学习的“相异构想”进行研究。结果表明,日常生活概念“平均”对科学概念“8电子稳定结构”学习产生了负迁移,同时高一学生对相关的化学微观概念产生了很多的相异构想;结合研究结果,提出一套中学化学微观概念教学模式。     

教师与学生部分核心化学概念相异构想的比较研究

通过对化学教师部分核心化学概念相异构想的调查研究,并与高一学生的研究结果相比较,发现教师与学生整体回答的曲线大致平行;教师及学生在“宏观—微观”、“微观—符号”表征转换方面存在困难。为了促进教师与学生相异构想的转变,应促进教师教学的反思,充分利用教材的资源,丰富学生相异构想的调查。     

化学概念理解水平的确定与测查研究——以酸碱反应概念理解测查工具的开发为例

为测量学生酸碱反应概念的理解水平,并诊断学生的相异构想,基于RASCH模型开发了酸碱反应概念理解的测查工具。使用该测查工具对752名高中生进行测试,分析显示测试结果有一定的信度和效度。研究还表明,中学生对酸碱反应概念的理解水平随年级升高而提高,但在不同的理解水平上学生均存在较多的相异构想。     

聚苯乙烯共混改性研究进展

综述了近年来用普通塑料,工程塑料和弹性体等共混改性聚苯乙烯的进展情况,提出了用纳米材料和反应挤出改性聚苯乙烯的构想。     

Investigation of the molecular surface area and volume: Defined and calculated by the molecular face theory

Based on the molecular face (MF) theory, the molecular face surface area (MFSA) and molecular face volume (MFV) are defined. For a variety of organic molecules and several inorganic molecules, the MFSA and MFV have been studied and calculated in terms of an algorithm of our own via the Matlab package. The MFV shows a very good linear relationship with the experimentally measured critical molar volume. It is also found that the MFSA and MFV have significant linear correlations with those of the commonly used hard‐sphere model and the electron density isosurface. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010     

Molecular dynamics search for magic numbers for silver and copper clusters

Isothermal molecular dynamics is used to find the magic numbers corresponding to clusters of fcc transition metals: silver and copper. To that end, we use both our own computer program with a tight-binding potential and well-known LAMMPS software whose standard package is designed to model metal systems by the embedded atom method. Regardless of the choice between two relaxation techniques (lowtemperature relaxation at 1 K and the variant involving a gradual temperature decrease with subsequent relaxation at 1 K), magic number 13 is detected that corresponds to the first term of the Chini series. At the same time, other magic numbers are also found that belong and do not belong to this series.     

Theseus: A new software package for the handling and analysis of thermal denaturation data of biological macromolecules

A new software package (THESEUS) has been assembled for the analysis of the DSC data, Concerning the thermal denaturation of biological macromolecules. The system is useful to obtain accurate physico-chemical information, bypassing the casual and systematic errors, very common in these experiments. It can also be used for handling data from other instruments and methodologies giving thermodynamic, spectroscopic or other kind of data as a function of temperature. Because many of the researches in this field are of exploratory nature and continuously new unfolding mechanisms are described or hypothesized in the current literature, we have written and assembled this powerful and flexible program of general applicability, in order to put the operator in a position to control each step of the calculation procedure and use his own experience for choosing the better way to solve unexpected problems.     

Modeling of the Microwave Initiated Emulsion Polymerization of Styrene

The emulsion polymerization of styrene, activated by microwave irradiation and conductive heating, was modeled using the Predici^® simulation package of CiT. Microwave activated initiation was modeled as adding a second conventional free‐radical chemical initiator, whose concentration is given by the intensity of microwave irradiation, and its “decomposition” kinetic rate constant is related to the ratio of monomer concentration to the rate of absorbed radiation. Most of the kinetic rate constants and model parameters used in the model were taken from the literature, in order to avoid unnecessary parameter estimation procedures. Model predictions of conversion, number and weight average molecular weights, for microwave and thermally activated systems, agree well with the experimental data reported in the literature, including experimental data previously reported by our own group.     

The dynamo library for molecular simulations using hybrid quantum mechanical and molecular mechanical potentials

The Dynamo module library has been developed for the simulation of molecular systems using hybrid quantum mechanical (QM) and molecular mechanical (MM) potentials. Dynamo is not a program package but is a library of Fortran 90 modules that can be employed by those interested in writing their own programs for performing molecular simulations. The library supports a range of different types of molecular calculation including geometry optimizations, reaction‐path determinations and molecular dynamics and Monte Carlo simulations. This article outlines the general structure and capabilities of the library and describes in detail Dynamo's semiempirical QM/MM hybrid potential. Results are presented to indicate three particular aspects of this implementation—the handling of long‐range nonbonding interactions, the nature of the boundary between the quantum mechanical and molecular mechanical atoms and how to perform path‐integral hybrid‐potential molecular dynamics simulations. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 1088–1100, 2000     

Kisik — a combined chemical information system for a minicomputer

A minicomputer-oriented chemical information system (CIS) based on three different Spectrometries, i.e. infrared, mass, and ¹³C-n.m.r., is described and discussed.The system has roughly the same characteristics as CIS's implemented on large mainframe computers: substructure search, library searches on various files, file manipulation, statistical handling of retrieved data, etc. The source package is very suitable and simple for moving the entire CIS from one computer to another. In addition, the system has the Option UPDATE that enables the user to create his own fεles and modify them easily; this is rather difficult and expensive to implement on larger systems because of the very high disk-space price to frequency-of-access ratio. However, the quantity of data is strongly dependent on the disk space. At the moment the system handles 1016 compounds, each of which is described by a chemical name, molecular formula and weight, two-dimensional structure image, infrared, mass, and ¹³C-n.m.r. spectra. All these data for one compound are linked on-line via the identity number of the compound so there is no delay in accessing any of the items mentioned. The entire data bank together with the program package has a 1.8 Mbyte requirement which fits well within the 2.5 Mbyte space available on the small disk used by a PDP $\text{11}\text{34}$ minicomputer.     

pFind 2.0: a software package for peptide and protein identification via tandem mass spectrometry

This paper describes the pFind 2.0 software package for peptide and protein identification via tandem mass spectrometry. Firstly, the most important feature of pFind 2.0 is that it offers a modularized and customized platform for third parties to test and compare their algorithms. The developers can create their own modules following the open application programming interface (API) standards and then add it into workflows in place of the default modules. In addition, to accommodate different requirements, the package provides four automated workflows adopting different algorithm modules, executing processes and result reports. Based on this design, pFind 2.0 provides an automated target-decoy database search strategy: The user can just specify a certain false positive rate (FPR) and start searching. Then the system will return the protein identification results automatically filtered by such an estimated FPR. Secondly, pFind 2.0 is also of high accuracy and high speed. Many pragmatic preprocessing, peptide-scoring, validation, and protein inference algorithms have been incorporated. To speed up the searching process, a toolbox for indexing protein databases is developed for high-throughput applications and all modules are implemented under a new architecture designed for large-scale parallel and distributed searching. An experiment on a public dataset shows that pFind 2.0 can identify more peptides than SEQUEST and Mascot at the 1% FPR. It is also demonstrated that this version of pFind 2.0 has better usability and higher speed than its previous versions. The software and more detailed supplementary information can both be accessed at http://pfind.ict.ac.cn/.     

MDAnalysis: A toolkit for the analysis of molecular dynamics simulations

MDAnalysis is an object‐oriented library for structural and temporal analysis of molecular dynamics (MD) simulation trajectories and individual protein structures. It is written in the Python language with some performance‐critical code in C. It uses the powerful NumPy package to expose trajectory data as fast and efficient NumPy arrays. It has been tested on systems of millions of particles. Many common file formats of simulation packages including CHARMM, Gromacs, Amber, and NAMD and the Protein Data Bank format can be read and written. Atoms can be selected with a syntax similar to CHARMM's powerful selection commands. MDAnalysis enables both novice and experienced programmers to rapidly write their own analytical tools and access data stored in trajectories in an easily accessible manner that facilitates interactive explorative analysis. MDAnalysis has been tested on and works for most Unix‐based platforms such as Linux and Mac OS X. It is freely available under the GNU General Public License from http://mdanalysis.googlecode.com . © 2011 Wiley Periodicals, Inc. J Comput Chem 2011     

PEACH 4 with ABINIT-MP: a general platform for classical and quantum simulations of biological molecules

A program package for molecular simulations of biological molecules was developed. The package, "PEACH version 4 with ABINIT-MP version 20021029," was constructed by incorporating ABINIT-MP, a program for the fragment molecular orbital (FMO) method [Chem.Phys. Lett. 313 (1999) 701], into PEACH, a program package for classical molecular dynamics simulations (MD). A few capabilities of the package were demonstrated. First, high parallel efficiency of FMO was demonstrated in a single point calculation of a protein. Second,FMO-MD simulations [Chem. Phys. Lett. 372 (2003) 342] of a peptide were performed with and without explicit solvent, and the simulations showed the influence of the solvent on the electronic state of the peptide.