{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# Structure.questions_VI_answer - Show that Pauling’s first...

This preview shows pages 1–2. Sign up to view the full content.

MTLE-2100 Structure of Engineering Materials, Questions VI-Answer 1. Lead screens for the protection of personnel in x-ray diffraction laboratories are usually at least 1 mm thick. Calculate the transmission factor, I trans /I incident , of such a screen for Cu K α , Mo K α , and the shortest wavelengh radiation from a tube operated at 30,000 volts. ρ =11.34 g/cm 3 . λ μ / ρ μ x 0.1 I trans /I incident Cu K α 1.54Å 233.1 264.3 1.7E-115 Mo K α 0.711Å 122.8 139.3 3.3E-61 λ SWL (12400/30KV) 0.413 Å33 37.4 5.8E-17 (by extrapolation) 2. Calculate the breadth B (in degrees of 2 θ ) due to the small crystal effect alone, of the powder pattern lines of particles of diameter 1000, 750, 500 and 250 Å . Assume θ = 45 ° and λ = 1.5 Å . For particles 250 Å in diameter, calculate the breadth B for θ = 10, 45 and 80 ° . t= 0.9 λ /Bcos θ B . B= 0.9 λ /tcos θ B 1000 Å . 0.00191 rad. = 0.11 ° 750 Å . 0.00255 rad. = 0.15 ° 500 Å 0.00382 rad. = 0.22 ° 250 Å . 0.00764 rad. = 0.44 ° 250 Å . θ = 10 ° 0.00548 rad. = 0.31 ° 45 ° 0.44 ° 80 ° 0.0311 rad. = 1.78 ° 3. CsCl structure has Cl at corners of cubic cell and Cs at the body center position.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Show that Pauling’s first and second rules apply to the compound CsCl. r Cs+ = 1.67 Å , r Cl-= 1.81 Å . r/R = 1. 67 Å /1.81 Å =0.92. CN=8 is expected since the ratio is between 0.73—1.0. Strength of Cs +-Cl- bond = 1/8. Valence of anion, Cl, is one 1 = (CN around Cl) x (1/8). CN around Cl is 8. These are consistent with CsCl structure. 4. What is piezoelectricity? Applied electric field results in setting up an electric charge on the surface of a material. Conversely when an electric field is applied to the material, the material expands in one direction and contract in another direction. 5. What is the glass transition temperature? Temperature separating the super-cooled liquid state from glassy state. 6. What is a polymorphic transformation? Transformation between different crystal structures with the same chemical composition....
View Full Document

• Spring '08
• Tomozawa
• Glass, Glass transition, CsCl structure, small crystal effect, shortest wavelengh radiation, x-ray diffraction laboratories

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern