Recent content by Guilherme Franco

Hi I'm preparing some BCNO phosphor samples. Their basic structure is hexagonal Boron Nitride (h-BN) but it's doped with carbon and oxygen. The simplest BCNO phosphors are usually made from urea and boric acid alone, this already produces a BN structure with C and O impurities. I'm trying to...

I think the answer for this may be straightforward, but I don't see anywhere that explains this from the scratch: A large resonant cavity with a small hole is used to approximate an ideal black body. I understand the conditions for the modes inside the cavity. But there are two points that...

I'm seemingly having problems of having too much evaporation of urea in the preparation of a gel. The gel is formed by drying the components in a water mixture, and it takes hours to dry at 70 ºC and dries much faster at 100 ºC (also produces a gel with better consistency), but at 100ºC it seems...

I'm trying to find a good database of absorption or reflection spectra in visible light for pigments. I've found a wonderful database in this article: http://e-conservation.org/issue-2/36-FORS-spectral-database#CSV It's almost exactly what I needed Except I don't understand the data The...

I was just being specific about what I wanted to know. The question is just that, when looking with keywords associated with heavy element migration towards the core, I didn't found any of this. Now, another question if you know: Does volcanic activity bring up material from layers deep enough...

Let me be more specific: I'm needing some source that talks, in a more broad way, about how heavier elements tend to "sink into the core" during Earth's formation (when we're talking about siderophile elements, that readily combine with molten iron). Wikipedia's page about the Goldschmidt...

Interestingly, in my case, if I sum up all measures (propagating the error to the sum) and then divide everything by 3 (the value and the error), I get to the exact same value of 0.005/sqrt(3), because the error would be sqrt(3*(0.005²))/3 doing like that. Just a coincidence though, if I tried...

My question is simple, and I'm only asking it because most places talk about more advanced problems than this one: I've measured the radius of a sphere (a very regular one) with a micrometer of 0.01 mm resolution. I took 3 measures (rotating it between each measure), and all of them were...

My question might seem simple, however I couldn't find data on this. Let me explain my situation: I'm involved in a project about the formulation of new criteria to avaliate exoplanetary systems for search of extraterrestrial intelligence. The key question is mostly around the element...

Hello. I couldn't sum my entire question in the title, so here it goes: I have a friend that needs information about the content of Iodine and Molybdenum in stars (from as much stars as he can). There are references to the content of many stars in books and papers, but most of them don't give...