Recommended Interesting Articles

Chemistry

Step reactions

Use of polyethylene terephthalate The main areas of application for PET are the production of fibers, molding compounds, hollow bodies and foils. The material is used in continuous filaments, staple fibers, crimped fibers, felts or tow for clothing fabrics, home textiles and industrial purposes. They are also used in blends with other fibers such as cotton, wool, silk and synthetic fibers in the form of woven and knitted fabrics into outer and underwear, coats, ties, furniture covers, bed linen.
Read More
Chemistry

Special polymer architectures

Synthesis of Polycatenans The formation of catenans occurs through covalent ring closure reactions in which another ring is included. In order to obtain the desired topology, templates are usually used. The molecules adopt the arrangement in the coordination sphere of a transition metal that leads to an intertwined form when the ring closes.
Read More
Chemistry

Systems of linear ordinary differential equations of the second order

Oscillating balls We consider three balls with the same mass m, which are connected by two springs with the same spring constant k. We denote the displacements of the masses from the equilibrium positions by x1, x2 and x3. Newton's law says for the equations of motion: mx⋅⋅1 = -k (x1-x2) mx⋅⋅2 = -k (x2-x1) -k (x2-x3) mx⋅⋅3 = -k (x3 -x2).
Read More
Chemistry

Group speed

Subject - PhysicsWhen wave packets are propagated, which arise when several plane waves of different wavelengths are superimposed, a distinction is made between the phase velocities of the individual waves and the group speed with which the entire wave packet is propagated. In the propagation of wave packets, which arise when several plane waves of different wavelengths are superimposed, a distinction is made between the phase velocities of the individual waves and the group velocity with which the entire wave packet is propagated.
Read More
Chemistry

Gravity

Subject - Physics In our daily life, gravity is, besides electromagnetic interaction, the most important force, as it influences all our movements. Gravity describes the mutual attraction of masses. Both planetary motion (Kepler's laws) and the free fall of bodies are determined by gravity.
Read More