Surface意思

Indian Energy advected to and from the lake by precipitationsurface water, surface意思, and ground water had little effect on evaporation rates. North American It enters the soilsurface water and eventually the ground water. New Zealand The reservoirs store rainwatersurface意思, groundwater surface意思, and surface water until water is needed on the field.

English images. English synonyms. Times, Sunday Times It is used to make bread , cakes , and pastry. Chinese Quiz.

Surface意思

Surface states are electronic states found at the surface of materials. They are formed due to the sharp transition from solid material that ends with a surface and are found only at the atom layers closest to the surface. The termination of a material with a surface leads to a change of the electronic band structure from the bulk material to the vacuum. In the weakened potential at the surface, new electronic states can be formed, so called surface states. The allowed wave numbers for a given potential are found by applying the usual Born—von Karman cyclic boundary conditions. Consequently, if the cyclic boundary conditions are abandoned in the direction normal to the surface the behavior of electrons will deviate from the behavior in the bulk and some modifications of the electronic structure has to be expected. A simplified model of the crystal potential in one dimension can be sketched as shown in Figure 1. The step potential solid line shown in Figure 1 is an oversimplification which is mostly convenient for simple model calculations. At a real surface the potential is influenced by image charges and the formation of surface dipoles and it rather looks as indicated by the dashed line. The first type of solution can be obtained for both metals and semiconductors. In semiconductors though, the associated eigenenergies have to belong to one of the allowed energy bands. The second type of solution exists in forbidden energy gap of semiconductors as well as in local gaps of the projected band structure of metals. It can be shown that the energies of these states all lie within the band gap. As a consequence, in the crystal these states are characterized by an imaginary wavenumber leading to an exponential decay into the bulk.

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Add to word list Add to word list. B2 [ C ] the outer or top part or layer of something:. Tropical rain forests used to cover ten percent of the earth's surface. The marble has a smooth , shiny surface. Neil Armstrong was the first person to set foot on the surface of the moon.

We'll need a flat surface to play the game on. Teeth have a hard surface layer called enamel. These plants float on the surface of the water. She's cleaned all the kitchen surfaces. Rage bubbled just below the surface of his mind.

Surface意思

Add to word list Add to word list. B2 [ C ] the outer or top part or layer of something. The marble has a smooth , shiny surface. Neil Armstrong was the first person to set foot on the surface of the moon. Don't put anything wet on a polished surface, or it will leave a mark. She watched the sunlight dancing on the water's surface. Pollution has decayed the surface of the stonework on the front of the cathedral.

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In this picture, it is easy to comprehend that the existence of a surface will give rise to surface states with energies different from the energies of the bulk states: Since the atoms residing in the topmost surface layer are missing their bonding partners on one side, their orbitals have less overlap with the orbitals of neighboring atoms. We have almost lists of words from topics as varied as types of butterflies, jackets, currencies, vegetables and knots! These states exist in the forbidden energy gap only and are therefore localized at the surface, similar to the picture given in figure 3. Add to word list Add to word list. The trial may take more than a year to. Read Edit View history. ISBN X. Surface states originating from clean and well ordered surfaces are usually called intrinsic. Much of it was left by American astronauts who landed on the lunar surface between and during NASA's Apollo missions. I suspect that such factors as "inter-reflections between surfaces," though certainly demonstrable and interesting, are of secondary importance even in most natural environments. Kittel Eggs provide a unique surface to paint on. In the tight binding approach, the electronic wave functions are usually expressed as a linear combination of atomic orbitals LCAO , see figure 5.

These may bind to receptor molecules on the surfaces of cells. The volume of gas trapped on these surfaces can be considerable.

Teeth have a hard surface layer called enamel. Basic Theory of Surface States. Social unrest, never far below the surface in Brazil, has erupted over the last few days The board is expected to meet today to consider a formal takeover proposal. As a consequence, in the crystal these states are characterized by an imaginary wavenumber leading to an exponential decay into the bulk. Here's our quick guide to get you speaking like a true bardd! Word of the Year. Zotov; M. Conngratulating someone shows you care about their successes or life events. Your feedback will be reviewed. The nearly free electron approximation can be used to derive the basic properties of surface states for narrow gap semiconductors.