I've been reading up on mercury vapor lamps, which are often used as a light source in fluorescence microscopes. I still don't understand why it decreases the lamp's lifetime if you turn it on and switch it off without waiting 20 - 30 minutes. Is there a reason for this?
Are there also filters that only allow two ranges of wavelengths to pass through as opposed to one? Basically a band pass filter with two regions of transmission. I'm sorry, I'm having little luck finding this online for some reason.
In fluorescence microscopy, dichroic mirrors reflect light under a critical wavelength (used to excite the sample) and transmit light over a critical wavelength (emission light from the sample). Are there mirrors that reflect two different wavelengths of light and transmit the rest? Essentially...
I'm confused about which phases are considered compressible and which are considered non-compressible.
In classical thermodynamics, gases and liquids are considered compressible. This is what the state principle (2 independent properties define all other properties) applies to gases and...
So if the tangent of the phase angle varies as frequency varies, is there a standard frequency people use to measure the tangent of the phase angle to compare the viscoelasticity of different polymers?
I understand that the dynamic modulus of a material is measured by inducing a sinusoidal force and measuring the strain response. Usually one gets a value for the storage and loss modulus. However, I don't understand how one would "quantify" how viscous a material is. I know a viscous material...
What if the material is isotropic and bulk (on the macroscale). But I'm talking about a situation in which the force exerted, and the area it is exerted on, is on the micro-scale.
Does Young's Modulus change with drastic changes in size? For example, suppose you exert a force on the micro scale or maybe even the nano scale. Would the same Young's modulus uphold at such a small scale?
I'm planning to deposit a thin layer of a gel (~10 - 100 uM), which will later be heat cured using a spin-coater. I've looked at a few models to predict the thickness of the gel based on experimental parameters (rpm, viscosity, time, etc.) but am still unsure on which model is the best to go...
I have been reading up on PALM works and am still confused about a few things. In particular, (1) how can you only excite a few molecules at a time and then only photobleach those molecules? Won't other molecules also automatically be excited and eventually photobleached? (2) When you fit the...
I have only taken chemistry I and II at the college level (introductory classes) and for physics I have taken a course on waves, oscillations, and quantum physics (which is a little above the level of an introductory college course).
Thanks for the reply. I have some few questions though,
1) how can the electron fall back to the ground state without radiating anything? If the explanation is too complicated I can just take this for granted.
2) Does intersystem crossing only occur if the electron falls back without...
Can someone explain the cause behind photobleaching (http://en.wikipedia.org/wiki/Photobleaching) of fluorophores when they are continuously excited. The wikipedia article does not really explain why photobleaching occurs.
I tried looking it up online, and most explanations were too...
I'm going though the particle in a box lesson in my physics textbook right now. I understand all the math, but don't understand a lot of the physics behind it. Also this is an intro physics course, we're only covering the basics of quantum mechanics and not going into too much detail.
How come...
For one of my physics classes (oscillations, waves, quantum mechanics) we use Young and Freedman University Physics 13th edition. However, the lectures given by the professor are usually more difficult/ on a higher level than the textbook.
For example, right now we're learning about...