نتایج جستجو برای: retention index

تعداد نتایج: 461268  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیخ بهایی - دانشکده زبانهای خارجی 1391

the skill of reading in english as a foreign language is an important and challenging one which is affected both by linguistic and extra linguistic factors. since vocabularies are part and parcel of every reading comprehension text, knowing enough vocabulary always facilitates this process. however, guessing strategy as one of the most important strategies has consistently ignored by language l...

Journal: :Journal of chromatographic science 2001
I Rykowska W Wasiak

Specific interactions of aliphatic linear and branched hydrocarbons as well as cyclic and aromatic hydrocarbons with new packings containing chemically bonded complexes of transition metals are studied. The possibility of using these packings to separate these compounds is also discussed. The packings under study contain complexes of Cu(II) and Cr(III) chemically bonded to the silica surface. C...

Journal: :Phytochemical analysis : PCA 2009
Mary Lucero Rick Estell María Tellez Ed Fredrickson

INTRODUCTION Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chro...

2010

Some food characteristics, like stickiness and consistency, can modify the time for food removal from the mouth as well as favors the activity of cariogenic bacteria, increasing dental caries risk. This study aimed to observe food retention in contact with a cariogenic substrate in 24-30 months old children. Therefore, 27 children (54 teeth) were evaluated. They intake a chocolate cookie and th...

2003
William P. Eckel Tobias Kind

Gas chromatographic (GC) retention indices are useful for reviewing mass spectral library searches for the tentative identification of organic compounds. If the known GC retention index (RI) of a compound that ranks high on the (gas chromatography-mass spectrometry) GC-MS library search “hit list” matches the RI of the unknown, there is a strong presumption that a correct identification has bee...

Journal: :جنگل و فرآورده های چوب 0
حسین جلالی ترشیزی عضو هیات علمی دانشگاه شهید بهشتی فریبا خلیلی نفت چالی دانش آموخته کارشناسی ارشد حسین کرمانیان عضو هیات علمی دانشگاه شهید بهشتی

by increasing demands on paper products and shortage of fiber resources, various strategies were introduced to meet the requirements. in this context, application of mineral fibers is a novel and growing approach. this study was aimed to reduce the plant fibers by application of, mineral fiber in the papermaking system. application of 0, 10, 20, and 30% loadings of rock wool mineral fibers (rwm...

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد گرمسار - پژوهشکده علوم انسانی و اجتماعی 1390

this study was an attempt to investigate and compare the effect of lexical inferencing and concept mapping on developing vocabulary retention of iranian language learners. sixty homogeneous students from different intact classes who were being taught as intermediate learners in sokhan english institute participated in this study. they were in different classes. a teacher made test as a pre-test...

2017
Zhenhua Liu Xinping Li Wei Xie

Carrageenans are commercially important sulfated gums found in various species of red seaweeds (Rhodophyta), wherein they serve a structural function similar to that of pectins in land plants. In this study, carrageenan was used independently or in combination with cationic polyacrylamide (CPAM) and/or Al2(SO4)3 to explore its application as a dry strength additive in papermaking. Strength inde...

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