检索结果-南通市图书馆

Systematic Method for Constructing Lewis Representations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Inorganic Chemistry 2024年第1期14卷 1-18页

作者： lahbib Abbas Lahcen Bih Khalid Yamni Abderrahim Elyahyaouy Abdelmalik El Attaoui Zahra Ramzi Materials Membranes and Nanotechnology Faculty of Science and Technology Moulay Ismail University Meknes Er-Rachidia Morocco Engineering Sciences and Professions Laboratory National School of Arts and Crafts Moulay Ismail University Meknes Meknes Morocco Materials Membranes and Nanotechnology Chemistry Department Faculty of Sciences Moulay Ismail University Meknes Meknes Morocco Physics Department Faculty of Sciences Ibn Tofail University Kenitra Morocco Laboratory of Molecular Chemistry Materials and Environment (LCM2E) Multidisciplinary Faculty of Nador Mohamed 1st University Oujda Nador Morocco Laboratory of SCiMATOP Chemistry Department Faculty of Sciences Semlalia Cadi Ayyad University Marrakech Morocco

The systematic method for constructing Lewis representations is a method for representing chemical bonds between atoms in a molecule. It uses symbols to represent the valence electrons of the atoms involved in the bond. Using a number of rules in a defined order, it is often better suited to complicated cases than the Lewis representation of atoms. This method allows us to determine the formal charge and oxidation number of each atom in the edifice more efficiently than other methods.

关键词： Systematic Method Lewis Representation Chemical Bond Formal Charge Oxidation Number

Graphite Carbone Structure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Crystal Structure Theory and Applications 2024年第1期12卷 1-10页

作者： lahbib Abbas Lahcen Bih Khalid Yamni Abderrahim Elyahyaouy Abdelmalik El Attaoui Zahra Ramzi Materials Membranes and Nanotechnology Laboratory Faculty of Science and Technology Moulay Ismail University Errachidia Morocco Engineering Sciences and Professions Laboratory National School of Arts and Crafts Moulay Ismail University Meknes Morocco Materials Membranes and Nanotechnology Laboratory Chemistry Department Faculty of Sciences Moulay Ismail Univer-sity Meknes Morocco Physics Department Faculty of Sciences Ibn Tofail University Kenitra Morocco Laboratory of Molecular Chemistry Materials and Environment (LCM2E) Multidisciplinary Faculty of Nador Mohamed 1st University Nador Morocco Laboratory of SCiMATOP Chemistry Department Faculty of Sciences Semlalia Cadi Ayyad University Marrakech Morocco

Carbon graphite is a crystalline form of carbon consisting of layers of hexagonal carbon atoms arranged in a two-dimensional “graphene” structure. Graphene layers are stacked on top of each other, forming a three-dimensional structure with a high degree of anisotropy. The carbon atoms within each layer are linked together by strong covalent bonds, creating a strong, stable lattice structure. However, the layers themselves are held together by weak van der Waals forces, enabling them to slide easily over each other. The properties of carbon graphite are highly dependent on the orientation and alignment of the graphene layers. When the layers are aligned parallel to each other, the material exhibits high strength and stiffness along the alignment direction, but is weaker and more flexible in other directions. Carbon graphite is used in a variety of applications where high strength, rigidity and electrical conductivity are required. Some common applications include electrical contacts, electric motor brushes, and as a structural material in aerospace and defense applications. The aim of our work is to describe the structure of graphite, its physical and chemical properties and its applications.

关键词： Graphite Graphene Hexagonal Structure Hardness Rigidity Electrical Con-ductivity

Determination of Latent Heats of Vaporization and Fusion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Chemical Engineering and Science 2024年第3期14卷 113-124页

作者： lahbib Abbas Lahcen Bih Khalid Yamni Abderrahim Elyahyaouy Abdelmalik El Attaoui Zahra Ramzi Chemistry Department Faculty of Science and Technology Moulay Ismail University Meknes Er-Rachidia Morocco Engineering Sciences and Professions Laboratory National School of Arts and Crafts Moulay Ismail University Meknes Meknes Morocco Materials Membranes and Nanotechnology Chemistry Department Faculty of Sciences Moulay Ismail University Meknes Zitoune Mekns Morocco Physics Department Faculty of Sciences Ibn Tofail University Kenitra Morocco Laboratory of Molecular Chemistry Materials and Environment (LCM2E) Multidisciplinary Faculty of Nador Mohamed 1st University Oujda Nador Morocco Laboratory of SCiMATOP Chemistry Department Faculty of Sciences Semlalia Cadi Ayyad University Marrakech Morocco

Water is the most abundant liquid on the surface of the earth. It is a liquid whose properties are quite surprising, both as a pure liquid and as a solvent. Water is a very cohesive liquid: its melting and vaporization temperatures are very high for a liquid that is neither ionic nor metallic, and whose molar mass is low. Thus, water remains liquid at atmospheric pressure up to 100C while similar molecules such as H2S, H2Se, H2Te for example would give a vaporization temperature close to 80C. This cohesion is in fact ensured by hydrogen bonds between water molecules. This type of bonds between neighboring molecules, hydrogen bonds, is quite often found in chemistry [1] [2]. Any change in the state of aggregation of a substance occurs with the absorption or release of a certain amount of latent heat of transformation. Latent heat of fusion, vaporization or sublimation is the ratio of the energy supplied as heat to the mass of the substance that is melted, vaporized or sublimated. As a result of the reversibility of the processes, the fusion heat is equal to the heat released in the reverse process: crystallization and solidification heat. And likewise the heat of vaporization is equal to the heat of condensation. This equality of heat is often used to determine experimentally either of these quantities. There are two main measurement methods: 1) Direct measurement using the calorimeter, 2) Indirect measure based on the use of the VantHoff relationship. The objective of this work is to measure the latent heat of water vaporization and verify the compatibility of the experimental values with the values given by the tables using the indirect method.

关键词： Latent Heat of Vaporization Latent Heat of Fusion Calorimetry Relationship of Vant’Hoff

Chemical composition of Rosmarinus and Lavandula essential oils and their insecticidal effects on Orgyia trigotephras(Lepidoptera,Lymantriidae)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2015年第2期8卷 98-103页

作者： Ben Slimane Badreddine Ezzine Olfa Dhahri Samir Chograni Hnia Ben Jamaa mohamed lahbib Institut Superieur des Sciences et Technologies de l'Environnement de Borj-Cédria B.P.1003Hammam-Lif 2050-Tunisia Institut National de Recherche en Génie Rural Eaux et ForêtsTunis.Tunisia Institut National des Sciences Appliquees et Technologiques.Tunis.Tunisia

Objective:To evaluate toxic activities of essential oils obtained from Rosmarinus officinalis and Lavandula stoechas against the fourth larval instars of Orgyia ***:A total of 1 200 larvae were divided into three groups Ⅰ,Ⅱ,Ⅲ.Group Ⅰ was to investigate the effect of extracted essential oils from these aromatic plants as gastric *** thuringiensis and ethanol were used as control *** Ⅱ was used as contact action and Group Ⅲ was used as fumigant *** and ethanol were used as control *** the three experiments,the effect of essential oils on larvae was ***:The chemical composition of essential oils from two medicinal plants was determined and,their insecticidal effects on the fourth larval slate of Orgyia trigotephras were *** two simples presented an insecticidal activity,nevertheless Rosmarinus officinalis essential oil was less efficient compared to Lavandula stoechas one are ***:The relationship between the chemical composition and the biologieal activities is confirmed by the present *** the potential uses of these essential oils as bioinsecticides can he considered as an alternative to the use of synthetic products.

关键词： Rosmarinus Lavandula Orgyia trigotephras Essential oils Insect control

Offline Handwritten Characters Recognition Using Moments Features and Neural Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Computer Technology and Application 2015年第1期6卷 19-29页

作者： mohamed Abaynarh lahbib Zenkouar Laboratory of Electronics and Communication Faculty and Name of Institute Ecole Mohammadia d'Ingenieurs Avenue IbnsinaB.P. 765 Agdal Rabat 10000 Morocco

In this paper we revise the moment theory for pattern recognition designed, to extract patterns from the noisy character datas, and develop unconstrained handwritten. Amazigh character recognition method based upon orthogonal moments and neural networks classifier. We argue that, given the natural flexibility of neural network models and the extent of parallel processing that they allow, our algorithm is a step forward in character recognition. More importantly, following the approach proposed, we apply our system to two different databases, to examine the ability to recognize patterns under noise. We discover overwhelming support for different style of writing. Moreover, this basic conclusion appears to remain valid across different levels of smoothing and insensitive to the nuances of character patterns. Experiments tested the effect of set size on recognition accuracy which can reach 97.46%. The novelty of the proposed method is independence of size, slant, orientation, and translation. The performance of the proposed method is experimentally evaluated and the promising results and findings are presented. Our method is compared to K-NN （k-nearest neighbors） classifier algorithm; results show performances of our method.

关键词： Neural network character recognition orthogonal moments pattern recognition.

Chemical composition of Rosmarinus officinalis and Lavandula stoechas essential oils and their insecticidal effects on Orgyia trigotephras(Lepidoptera:Lymantriidae)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Coastal Life Medicine 2015年第1期 64-69页

作者： Ben Slimane Badreddine Ezzine Olfa Dhahri Samir Chograni Hnia Ben Jamaa mohamed lahbib High Institute of Environmental Sciences and Technology Borj-Cédria Technopole2050 Hamam-LifTunisia National Research Institute of Rural Engeneering Waters and ForestryBP N°102080 TunisTunisia National Institute of Applied Sciences and Technology BP 6761080 TunisTunisia

Objective:To evaluate toxic activities of essential oils obtained from Rosmarinus officinalis and Lavandula stoechas against the fourth larval instars of Orgyia ***:A total of 1200 larvae were divided into three groups-I,II,*** I was to investigate the effect of extracted essential oils from these aromatic plants as gastric *** thuringiensis was used as referencee and ethanol as *** II was used as contact action and Group III was used as fumigant *** both Groups II and III,Decis was used as reference and ethanol as *** the three experiments,the effect of essential oils on larvae was ***:The chemical composition of essential oils from two medicinal plants was determined,and their insecticidal effects on the fourth larval state of Orgyia trigotephras were *** presented an insecticidal *** officinalis essential oil was less efficient compared to Lavandula ***:The relationship between the chemical composition and the biological activities is confirmed by the present *** the potential uses of these essential oils as bioinsecticides can be considered as an alternative to the use of synthetic products.

关键词： Rosmarinus officinalis Lavandula stoechas Orgyia trigotephras Essential oils Insect control