نتایج جستجو برای: low to high molecular weights
تعداد نتایج: 11397681 فیلتر نتایج به سال:
asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...
In this work, crosslinkers were prepared by conjugating high- and low-molecular-weight gelatin with different mole ratios of itaconic acid (IA) with double bonds. Then, the gelatin-itaconic acid (gelatin-IA) crosslinkers were compared with the gelatin-methacrylate (gelatin-MA) crosslinkers. The molecular weights and structures of gelatin-MA and gelatin-IA were confirmed using gel permeation chr...
morphological changes in polyvinyl butyral (pvb) electrospun nanofibres can be acquired by preparation of pvb spinning solution in different solvents. accordingly, three solvents, including ethyl alcohol, n-butanol and isopropanol, with diverse physical properties (e.g. boiling point, density, dipole moment and dielectric constant) were used to prepare polyvinyl butyral (pvb) spinning solution...
dendrimer synthesis strategies now provide virtual control of macromolecular nanostructures as a function of size and surface/interior functionality. these strategies involve the covalent assembly of hierarchical components reactive monomers , branch cells or dendron’s around atomic or molecular cores according to divergent/convergent dendrite branching principles.combinon of two or more dendri...
in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...
rested on sociocultural theory (sct), this study attempted to examine the effect of written corrective feedback (wcf) followed by producing written languaging on developing writing accuracy over new tasks. to this aim, two intact iranian efl classes at the low-intermediate level were randomly assigned to two experimental groups: direct (n = 25) and indirect (n = 25). both groups wrote on a numb...
High strength and elastic biodegradable membranes are of great demand in modern technology. Similar membranes have been developed by irradiating different weight poly (vinyl alcohol) (PVA) – hydroxypropyl guar gum (HPG) blends and followed by combining with ex situ nanosilica. Polarized light microscopic (PLM) study indicates that electron beam irradiation produced crosslinks and develop...
the identification of natural hazard prone areas for future planning requires an efficient decision support tool to provide the appropriate weights for the various topographical, geological, and seismological factors responsible for the expected hazards. in the present study, an analytical hierarchy process (ahp) with six earthquake hazard parameters (ehps) was used as a decision support system...
abstract the third millennium has started, but the world is facing with serious challenges in achieving international security and peace. various human rights violations have lead the states to find means to protect human rights. also article 55 of the united nations charter introduces the respect to human rights and fundamental freedom as the most suitable ways to realize peace and security. ...
toury (1978:200) believes that translation is a kind of activity which inevitably involves at least two languages and two cultural traditions. being polite while asking for something takes place differently in different cultures and languages, therefore various strategies may be applied for making requests and also translation of them in order not to disturb or threaten the face or better to sa...
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