What is the best method for tracking the sun position, is-it by solar position calculation along the day of the year or by other method?

In solar energy application, often we should know the sun position at each instant. With the sun position calculation, I think we can establish a database for this purpose. Then we can use-it for...

31 December 2014 7,264 12 View

In multilayer PV solar cells, how can I choose the materials (gap and contact type) in order to increase efficiency ?

When the PV solar cell is used in a multi layer form, the goal is to benefit of a large interval of solar radiations. I think that the gap and the contact of different layers must have certain...

31 December 2014 3,584 4 View

What is the energy value of a phonon generally measured in an indirect transition?

Is it possible to obtain a phonon energy of about 425 meV, or is it an indirect transition assisted with more than one phonon?

11 December 2014 6,267 1 View

Why we use the term of "optical constants" of a material in spite of their variations ? is-it by misnomer ?

Optical constants as well as the gap, represent the signing of a material. They must be specific for this material. However, optical constants depend of the size of the crystallites which form the...

11 December 2014 5,742 3 View

Can we predict barrier potential in a contact metal-semiconductor or semiconductor-semiconductor using a theoretical approach ?

From band structure obtained with an existing calculation method , can we reach the result relating to the contact barrier between two materials ?

11 December 2014 5,487 13 View

There are much old films which are colored later. How we proceed to retrieve the suitable color for original picture ?

There are much old films which are colored later. The obtained result seems to be satisfactory. The colors can be different from the originals but it is sufficient for mistaking the human eyes....

11 December 2014 8,546 1 View

The IR radiations are harmful for the performances of photovoltaic solar cells; how is-it possible to eliminate these kind of radiations ?

Among the parameters which decrease the efficiency of the photovoltaic solar cells, we can note the solar IR radiations. This kind of radiation increases the temperature and then disturbs often...

11 December 2014 447 17 View

Is it possible to obtain a natural colored image using electron microscopy or ecography ?

Until today, a good colored image is obtained using exclusively light. Electron microscope uses electrons and echograph uses ultrason. That gives only gray images.

10 November 2014 7,733 11 View

What kind of chemical products are generally used in order to target a given thin film by the CBD technique?

08 September 2014 9,211 2 View

Why does the energy gap of a quantum dot vary with its dimension?

Because of the gap of each material represents a signature of this material, why is it not the case for a quantum dot made with the given material.

01 February 2014 8,339 3 View

flexibility of polymers chain

effect of double bond on the flexibility of polymers

07 April 2021 0 0 View

Formulation of polymer color flakes

I am writing to request some information for making polymer color flakes. I would appreciate the help.

17 March 2021 0 0 View

Physics: Why do we describe light by referring to its wavelength, but microwaves and radar pulses by referring to their frequency?

In physics, the description of the properties of light generally refers to its wavelength (nm), while in the range of microwaves and radio waves we refer to the frequency of a signal (e.g. kHz or...

03 March 2021 1,682 3 View

Why can't make aluminum nitride film successfully by use sputter?

We use reactive sputtering process to make aluminum nitride film, and want to make c-axis aluminum nitride film on a silicon substrate, but the crystal orientation cannot be seen with...

03 March 2021 7,975 3 View

What is the production process of CaFe ferroalloys?

I looking for ferro calcium production process

03 March 2021 1,755 4 View

Why are the velocities so high in my Boussinesq approximation Fluent simulation?

Hello, I have a mechanism where air rises due to convective flows. In this simulation, nothing is driving the air except this. I understand that the Boussinesq approximation only works for small...

02 March 2021 4,910 3 View

12% ledeburitic cold work tool steel, etched for revealing retained austenite, any help for clarifying?

Hello everyone. Given microstructure image belongs to a 12% ledeburitic cold work tool steel (annealed and tempered). The sample was etched with picral (100 mL ethanol and 4 g picric acid). I...

02 March 2021 4,119 3 View

Why almost every element would be metallized in sufficiently high pressure and low temperature?

(This statement is from wikipedia, BTW). What is so special about metallic bond that is limiting high-P low-T state of a matter (as long as individual atoms exist, not white dwarf of neutron star...

02 March 2021 3,309 2 View

What are anisotropic electrical and optical properties of a semiconductor due to?

In some materials, properties such as band gap, thermal conductivity differ along different crystallographic axes. What are the basics?

01 March 2021 1,923 3 View

Shall I skip the measurement model in SmartPLS?

Hello everyone, I had run a mediation model in SmartPLS using questionnaires that were already validated among my statistical population. A professor who edited my paper -though she is not...

01 March 2021 3,052 3 View