Hexagonal close packing pdf

An Introduction to Hydrogen Embrittlement. An Intro to Pipeline Corrosion in Seawater. Follow Connect with us. Sign up. Thank you for subscribing to our newsletter! Connect with us. The hcp structure is very common for elemental metals, including: Beryllium Cadmium Magnesium Titanium Zinc Zirconium. Share this Term. Procedures 5 Ways to Measure the Hardness of Materials.

Don't miss the latest corrosion content from Corrosionpedia! Experimental Section 2. Myristyl-trimethylammonium bromide— MTAB b. Cetyl-trimethylammonium bromide — CTAB, c. Arginine-N-lauroyl amide dihydrochloride — ALA and d. The surfactants were also dissolved in 10 mM NaBr. Using the stock solution of DNA and of surfactants three types of sample preparation were applied Figure 1S in Supplementary Information : Method 1 - Particle formation, DNA solutions were added drop wise into gentle agitated surfactant solutions.

After 2h, the formed particles were separated by filtration from surfactant solution and washed with water, to remove the excess of surfactant and salt. For measurements the particles were open with a needle and fixed on a flat glass surface; Method 2 - Film formation on a flat surface, the DNA and surfactant solution were simultaneously sprayed on flat glass surface.

Method 3 - Film formation in capillaries, first the DNA solution was introduced in the capillary and then slowly the surfactant solution was added, after few seconds at the interface of the two solutions the film formation was observed.

Anisotropic liquid — crystalline phases give rise to typical birefringent textures under polarized light. Transmitted scattering was detected using a PSD 50 Hecus in 1D experiments with a pixel resolution of For the X-ray measurements, the gel particles and the films were dried.

All the measurements were done at room temperature under vacuum. The surfactant-DNA films were deposited on glass-plate. The q range obtained with our setup -1 was between 0. This mainly produces a widening of the peaks without a noticeable effect on the peak position. The instrumentally smeared experimental SAXS curves were fitted to numerically smeared models for beam size and detector width effects. The samples were oriented with respect to the incident beam using a high-resolution stepper motor.

The angle was kept between 0. The 2D images were analyzed with FIT2D software to obtain the one-dimensional spectra or radial cuts. Results and discussion 3. Several aspects inherent to the preparation procedure will be mentioned that affects the final properties of the particles.

The main purpose of this work was to investigate the nanostructure of cationic surfactant-DNA materials and lead to new insight into how drug delivery systems can be designed on the basis of appropriate phase behavior. The structure and properties of the studied complexes in thin film geometry can be significantly different from the bulk properties. The direct association of cationic surfactant to DNA decreases the effective charge of the nucleic acid, allowing the surfactant-DNA complex to form a membrane.

The formation and the stabilization of the DNA gel particles were earlier studied24, 18 using mixtures of DNA and cationic surfactants. In this work, the nanostructure of the obtained translucent, gel particles were studied in detail, in particular in the form of stable cationic surfactant-DNA films. The structure of the latter differs in hydrophobic chain length and also in the hydrophilic head group.

The studies were carried out on films obtained from the different methods please refer to the above section 2. The thicknesses of those films were between mm and they showed an opaque structure.

Measurements were carried out on dry films in vacuum. All complexes were found to be birefringent under the polarized light. The qualitative phase behavior of the materials was observed by microscopy, and the obtained results are presented in Figure 2. The first observation was the different texture of these complexes. Not clearly defined structures were observed. However, for the samples prepared by the different methods the coexistence of lamellar or hexagonal structure was mainly detected.

The appearance of the smoky texture and the presence of spherulites suggest a hexagonal structure Surfactant-DNA complexes additionally form some birefringent crystals with sharp edges, by method 2 dry film by spraying method.

Figure S5. The yellow-boxed region represents the defect-free crystalline domain, b the black-and-white converted image with the proper threshold delineating the boundary of the nanospheres Image-J. The red boxed regions are excluded for the analysis because of the apparent line defects from the initial assembly stage.

As can be seen in Figure S5b, the interparticle distance i. If included in analysis, those distances measured along the defect line would produce wider pitch measurements and present a bimodal distribution, which is obviously faulty.

Therefore, we did not use low-magnification image like Figure S5a and always analyzed 10,x images like Figure S5b for more accurate measurements. This analysis approach is rather time-consuming, but provides the accuracy needed for the pitch measurement and in evaluating the effect of stretching on pitch.

Finally, while the number of the nanospheres for analysis is small 80 or , the available measurements for pitches interparticle distances are much more.

The yellow-highlighted circles in Figure S5b are in a 10 by 8 array, which provides measurements. This is because each sphere is associated with 6 neighboring spheres in a hexagonal array and thus 6 pitch measurements.

We have collected the data from 3 different locations in each center vs. Figure S6. From d, the membrane ripping first happens at the edge between the adjacent gripping points. Let us improve this page! Submit Feedback.

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