Explain why gold coating is required when preparing samples for the scanning electron microscopy (SEM)?
Why are high energy electrons in a scanning electron microscope (SEM) used to bombard samples?
Tabulate the similarities and differences between TEM(Transmission electron microscopy) and SEM(Scanning Electron Microscopy) regarding (a) sample preparation (4), (b) processing (4), (c) instrumentation (4), (d) detection (4) and (e) the structures that can be observed (3), (f) staining (3), (g) IHC (4) and (h) ISH (4).
(1 mark) 2. What is chemical fixation and why is fixation important when preparing biological samples? (2 marks) 3. Describe the main steps involved in preparing a sample for transmission electron microscopy. (2 marks) 4. Describe how an image is formed with a transmission electron microscope. (2 marks) 5. Describe the main steps involved in preparing a sample for scanning electron microscopy. (2 marks) 6. Describe how an image is formed with a scanning electron microscope. (2 marks) 7. Briefly...
1. Fill out the following table by indicating which general technique (light microscopy (LM) or electron microscopy (EM]) could be used to observe each structure or phenomenon. Put "no" in the box if the technique could not be used. If light microscopy can be used, name one technique (bright-field, phase-contrast, fluorescence, etc.) that you think would be effective. You will find some useful information in Appendix 1 of this manual and Chapter 18 of your textbook. Structure or phenomenon Could...
Explain why the conservation laws of physics are not violated when a positron and an electron annihilate each other. (Note there are more conservation laws in physics than charge)
1. Explain why the spectral lines (wavelengths) associated with the energy released when the electron returns to the n = 1 level were not measured using any method. 2. Describe another method for identifying the metal ions (for the unknowns in the flame test portion) besides simply observing the colors of the flames. 3. For hydrogen, discuss what present quantum theory predicts for the position of the 1s electron?
Explain in detail why, where, and when non-standard codon:anticodon base pairing is required
When did the U.S. go off of the Gold Standard? 6) Explain the Trilemma. 7) Assume that there is a fixed exchange rate is overvalued, what can the central bank due to defend the currency? 8) What is the difference between a spot and forward exchange rate? 9) What is the current value of the Euro and Yen exchange rates? 10) If the Euro depreciates relative to the dollar, are American goods more or less expensive? Why?
1. Using basic electrostatic arguments, explain why an electron “in” the 2s orbital of neon is of higher potential energy than it would be “in” the 1s orbital. 2. Explain why is it that periods 2 and 3 of the periodic table have 8 elements apiece while periods 4 and 5 have 18 elements and why aren't there 18 elements in period 3? 3. How many orbitals exists when n=5, l=3? What are these orbitals called? Are these orbitals degenerate?...
Why are there only 1-4 states in this quantum well when in the quantum free-electron model there is a quasi-continuum of energy states? (i.e. what is different?) I Quantitatively measure the energies of the states and compare to the energy of the equivalent states in a single quantum well with the same parameters. Describe and explain what you observe. Why are there only 1-4 states in this quantum well when in the quantum free-electron model there is a quasi-continuum of...