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Tuesday, May 29, 2012

PowerPoint Presentation On Electron Probe Microanalysis

PPT On Electron Probe Microanalysis EPMA

Presentation Transcript:
1. Electron Probe MicroanalysisEPMA

2. What’s the point?
We utilize the x-rays produced by the electron microprobe for many research applications. There are other techniques, similar in some ways, that are worth discussing, that utilize x-rays for secondary x-ray fluorescence. Two in particular are: XRF (X-Ray Fluorescence), where x-rays from a sealed tube are used to produce x-rays by secondary fluorescence in samples of interest (traditionally a macro-technique) Synchrotron Radiation, where electrons are accelerated in ~10s-100s meters diameter rings, and then made to produce highly focused beams of extremely intense x-rays or light, which are then fed into many different types of experiments. The benefits of secondary x-ray fluorescence include very low detection limits (10s of ppm easy in 10 seconds, no backgrounds)

 3. XRF Basics
The basics of XRF are very similar to those of EPMA—we are dealing with characteristic x-rays and continuum x-rays— with the exception that we are doing secondary fluorescence : x-ray spectroscopy of our samples using x-rays coming out of a sealed tube to excite the atoms in our specimen. The big difference is that there is NO continuum generated in the sample (x-rays can’t generate the Bremsstrahlung), and we are using BOTH characteristic x-rays of the sealed tube target (e.g., Cr, Cu, Mo, Rh) AND continuum x-rays to generate the characteristic x-rays of the atoms in the sample. XRF has been a bulk analytical tool (grind up 50-100 grams of your rock or sample to analyze), though recently people are developing “micro XRF” to focus the beam on a ~100 mm spot.

 4. X-ray Sources
 The standard X-ray tube (top right) was developed by Coolidge (at GE) around 1912. It is desirable to produce the maximum intensity of x-rays; a Cu target tube might be able to deliver 2 kW. The limiting factor is the heat that the target (anode) can handle; cold water is used to remove heat. Higher power can be delivered by dissipating the heat over a larger volume, with a rotating anode (bottom right). However, this is not normally used for XRF.

5. X-ray Attentuation
 This figure shows the attenuation of the X-rays in the target (sample). In addition to photoelectric absorption (producing characteristic X-rays and photoelectrons [=Auger electrons]), the original X-rays may be scattered. There are two kinds of scattering: coherent (Rayleigh) and incoherent (Compton).

 6. X-ray Scattering
Coherent scattering happens when the X-ray collides with an atom and deviates without a loss in energy. An electron in an alternating electromagnetic field (e.g. X-ray photon), will oscillate at the same frequency (in all directions). This is useful for understanding X-ray diffraction (in depth). Incoherent scattering is where the incident X-ray loses some of its energy to the scattering electron. As total momentum is preserved, the wavelength of the scattered photon increases by the equation (in Å) where f is the scatter angle. Since f is near 90°, there will be an addition peak from the main tube characteristic peak at about 0.024Å higher wavelength

7. For More Info Please Refer Our PPT.

Friday, May 11, 2012

PowerPoint Presentation On Statistical Process Control

PPT On Statistical Process Control

Presentation Transcript:
1.Statistical Process Control

2.What is SPC ?
What is VSC ?
Why we use control charts ?
Plotting of control chart ...

3. The Arithmetic mean :
 Most of the time when we refer to the average of something we are talking about arithmetic mean only. To find out the arithmetic mean , we sum the values and divide by the number of observation. Advantages : it's a good measure of central tendency.It easily understood by most people Disadvantages :- Although the mean is reliable in that it reflects all the values in the data set, it may also be affected by extreme values that are not representative of the rest of the data.

4. The Median :
The median is a single value from the data set that measures the central item in the set of numbers.Half of the item lie above this point and the other half lie below it. We can find median even when our data are qualitative descriptions. For example we have five runs of the printing press the results of which must be rated according to the sharpness of the image. Extremely sharp, very sharp, sharp slightly blurred, and very blurred.

5. Mode :-
The mode is a value that is repeated most often in the data set. Infect it is the value with highest frequency.

6. For More Info Please Refer Our PPT.

Saturday, May 5, 2012

PowerPoint Presentation On Personality

PPT On Personality


  Presentation Transcript: 
1. Don't compare yourself with any one in this world. If you compare, you are insulting yourself.

2. No one will manufacture a lock without a key. Similarly God won't give problems without solutions.

3. Life laughs at you when you are unhappy... Life smiles at you when you are happy... Life salutes you when you make others happy...

4. Every successful person has a painful story. Every painful story has a successful ending. Accept the pain and get ready for success.

5. Easy is to judge the mistakes of others. Difficult is to recognize our own mistakes. It is easier to protect your feet with slippers than to cover the earth with carpet.

 6. No one can go back and change a bad beginning; But anyone can start now and create a successful ending.

7. If a problem can be solved, no need to worry about it. If a problem cannot be solved what is the use of worrying?

8. If you miss an opportunity don't fill the eyes with tears.  It will hide another better opportunity in front of you

 9. "Changing the Face" can change nothing. But "Facing the Change" can change everything. Don't complain about others; Change yourself if you want peace.

10. Mistakes are painful when they happen. But year's later collection of mistakes is called experience, which leads to success.

11. Be bold when you loose and be calm when you win. Heated gold becomes ornament.  Beaten copper becomes wires.   Depleted stone becomes statue.  So the more pain you get in life you become more valuable.

12. Thanks.
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