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Register a new userدراسة في كيمياء المنتجات الطبيعية لنبات الشيح السوري
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Aِl-Baath University رسالة ماجستير
Publication date
2017
fields
Chemistry
and research's language is
العربية
Created by
Shamra Editor
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عزلت ستة مركبات من الخلاصة الميتانولية المائية الخام لنبات الشيح السوري بواسطة طرائق الفصل الكلاسيكية والكروماتوغرافية
No English abstract
References used
George E (1932) Flora of Syria Palestine and Sinai 2nd , American Press Beirut
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Scientific literature analysis needs fine-grained named entity recognition (NER) to provide a wide range of information for scientific discovery. For example, chemistry research needs to study dozens to hundreds of distinct, fine-grained entity types
, making consistent and accurate annotation difficult even for crowds of domain experts. On the other hand, domain-specific ontologies and knowledge bases (KBs) can be easily accessed, constructed, or integrated, which makes distant supervision realistic for fine-grained chemistry NER. In distant supervision, training labels are generated by matching mentions in a document with the concepts in the knowledge bases (KBs). However, this kind of KB-matching suffers from two major challenges: incomplete annotation and noisy annotation. We propose ChemNER, an ontology-guided, distantly-supervised method for fine-grained chemistry NER to tackle these challenges. It leverages the chemistry type ontology structure to generate distant labels with novel methods of flexible KB-matching and ontology-guided multi-type disambiguation. It significantly improves the distant label generation for the subsequent sequence labeling model training. We also provide an expert-labeled, chemistry NER dataset with 62 fine-grained chemistry types (e.g., chemical compounds and chemical reactions). Experimental results show that ChemNER is highly effective, outperforming substantially the state-of-the-art NER methods (with .25 absolute F1 score improvement).
The aim of this study is improving the durability of precast products of Glass Fiber
Reinforced Concrete (GRC) and in the context of sustainability applications, reduction of
cement consumption and replacement of it with green materials. This study
has been done
to test the role of the natural pozzolan from Shihan Hill in As Suwayda as supplementary
cementing material by 10% -15% -20% - 25%, and to determine the effect of it on the
consistency and flexure strength over 180 days, as well as to test its role in improving the
micro-structure of the mixture by reducing the content of Ca(OH)2 and increasing C-S-H
& C-A-S-H gel, which were tested using X-Ray Diffraction (XRD) and Energy Dispersive
X-Ray (EDX) techniques, and as a result reduced the erosion of fibers as shown in images
by Scanning Electronic Electron Microscopy (SEM). Moreover the role of pozzolana has
been studied in controlling the degradation of the material over time which tested by
immersion in hot water 50° for 150 days and by drying – wetting cycles. Also the effect of
pozzolana on absorption, porosity and resistance of sulfates attacks was studied. The
results have shown that the used natural pozzolana has no negative effect on consistency or
mechanical properties, and it improved all the studied durability factors.
In this work Rosmarinus officinalis L. grown in Syria was studied. The
general characteristics of the whole plant, as well as the leaves and the flowers
were determined. It was shown that there are two varieties of Rosmarinus one
having violet flo
wers and the other having white flowers. The two varieties
were compared morphologically and they were in accord with what was
mentioned in the literature.
The two varieties were also compared chemically and it was possible to
explain the differences mentioned in the literature by differences in the
composition of the volatile oil.
The chemical study of the drug shows the quantity as well as the percentage
of its constituents. At last the main substitute of the drug used in Syria was
shown and compared with the main drug. It was shown that the composition of
the volatile oil of the substitute is different from the composition of the volatile
oil of Rosmarinus, thus it can not be used for the same purpose.
أجريت هذه الدراسة في مركز بوقا ( اللاذقية ) خلال 2015 و 2014 وهدفت إلى تقييم طرائق المكافحة الميكانيكية والكيميائية على نبات العليق
Chemical composition of the essential oil of the aerial parts of Artemisia
vulgaris L. (Asteracea), grown in Syria was determined by GC/MS. The oil
obtained by hydrodistillation, was found to contain 55 components, accounting
for 98.82 %.
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