Quasi-stationary states of electrons interacting with strong electromagnetic field in two-barrier resonance tunnel nano-structure

An exact solution of non-stationary Schrodinger equation is obtained for a one-dimensional movement of electrons in an electromagnetic field with arbitrary intensity and frequency. Using it, the permeability coefficient is calculated for a two-barrier resonance tunnel nano-structure placed into a high-frequency electromagnetic field. It is shown that a nano-structure contains quasi-stationary states the spectrum of which consists of the main and satellite energies. The properties of resonance and non-resonance channels of permeability are displayed.Comment: 8 pages, 3 figure

Optimization of quantum cascade laser operation by geometric design of cascade active band in open and closed models

Using the effective mass and rectangular potential approximations, the theory of electron dynamic conductivity is developed for the plane multilayer resonance tunnel structure placed into a constant electric field within the model of open nanosystem, and oscillator forces of quantum transitions within the model of closed nanosystem. For the experimentally produced quantum cascade laser with four-barrier active band of separate cascade, it is proven that just the theory of dynamic conductivity in the model of open cascade most adequately describes the radiation of high frequency electromagnetic field while the electrons transport through the resonance tunnel structure driven by a constant electric field.Comment: 10 pages, 2 figure

Non-perturbation theory of electronic dynamic conductivity for two-barrier resonance tunnel nano-structure

The non-perturbation theory of electronic dynamic conductivity for open two-barrier resonance tunnel structure is established for the first time within the model of rectangular potentials and different effective masses of electrons in the elements of nano-structure and the wave function linear over the intensity of electromagnetic field. It is proven that the results of the theory of dynamic conductivity, developed earlier in weak signal approximation within the perturbation method, qualitatively and quantitatively correlate with the obtained results. The advantage of non-perturbation theory is that it can be extended to the case of electronic currents interacting with strong electromagnetic fields in open multi-shell resonance tunnel nano-structures, as active elements of quantum cascade lasers and detectors.Comment: 10 pages, 2 figure

Renormalized energy of ground and first excited state of Fr\"{o}hlich polaron in the range of weak coupling

Partial summing of infinite range of diagrams for the two-phonon mass operator of polaron described by Fr\"{o}hlich Hamiltonian is performed using the Feynman-Pines diagram technique. Renormalized spectral parameters of ground and first excited (phonon repeat) polaron state are accurately calculated for a weak electron-phonon coupling at $T=0$ K. It is shown that the stronger electron-phonon interaction shifts the energy of both states into low-energy region of the spectra. The ground state stays stationary and the excited one decays at a bigger coupling constant.Comment: 12 pages, 5 figure

Energy spectrum of localized quasiparticles renormalized by multi-phonon processes at finite temperature

The theory of renormalized energy spectrum of localized quasi-particle interacting with polarization phonons at finite temperature is developed within the Feynman-Pines diagram technique. The created computer program effectively takes into account multi-phonon processes, exactly defining all diagrams of mass operator together with their analytical expressions in arbitrary order over the coupling constant. Now it is possible to separate the pole and non-pole mass operator terms and perform a partial summing of their main terms. The renormalized spectrum of the system is obtained within the solution of dispersion equation in the vicinity of the main state where the high- and low-energy complexes of bound states are observed. The properties of the spectrum are analyzed depending on the coupling constant and the temperature.Comment: 16 pages, 3 figures, 3 table

Modul pengembangan keprofesian berkelanjutan SD kelas awal terintegrasi pendidikan karakter : I kelompok kompetensi

Program Pengembangan Keprofesian Berkelanjutan bagi Guru merupakan tindak lanjut dari hasil Uji Kompetensi Guru(UKG) 2015 dan bertujuan meningkatkan kompetensi guru dalam melaksanakan tugasnya sesuai dengan mata pelajaran yang diampunya. Sebagai salah satu upaya untuk mendukung keberhasilan suatu program diklat, Direktorat Pembinaan Guru Pendidikan Dasar pada tahun 2017 melaksanakan review, revisi, dan mengembangkan modul paska UKG 2015 yang telah terintegrasi Penguatan Pendidikan Karakter(PPK) dan Penilaian Berbasis Kelas, serta berisi materi pedagogik dan profesional yang akan dipelajari oleh peserta selama mengikuti Program Pengembangan Keprofesian Berkelanjutan

Analisis Kekuatan Suspensi Pegas Daun Truk Dengan Metode Finite Element

Leaf spring suspension is used on vehicles with a large payload capacity.The leaf springs provide reflections due to the load value received. It will experience the toughest conditions in the repeated compressive loads, so the potential to fail due to fatigue limit of the material through . With often hold large loads so broken on experience spring leaves.This study aims to determine how the modeling and the strength of the leaf spring suspension trucks using Finite Element Method. The first step begins with a rear axle load calculation ,then analyzed are static loads such as heavy vehicles . Then proceed with leaf spring suspension geometry modeling. After modeling the geometry, the next step is modeling the load and pedestal. Type pedestal modeling performed in this research is the foundation of the model using fixed pedestal and roller..From Finite Element Method is , it is known the power of truck leaf spring suspension.Maximum tension that occurs in the leaf spring suspension is 233 MPa. While the materials used have the yield strength of 1158 MPa. From these results it can be calculated that the resulting safety factor is 4,9. Keyword:finite element method, leaf spring, yield strength, Solidworks, fixed and rolle

Black here, black there, black everywhere: using theatre to understand what being-black-in-the-world entailed during apartheid South Africa

When a Black person sees a display on stage of a fellow Black person getting killed by a White person, why do they not intervene to stop that killing from happening? One would answer, ‘Because it is just a performance. That Black person is not literally getting killed. It is all an act'. Fair enough. Then why does that spectating Black person get a heavy heart when he sees that killing being portrayed on stage? Is it because it is an experience he is familiar to? He has seen his fellow Blacks getting killed in front of his eyes. What does he do about what he sees on stage? What does the play do to his psyche? Richard Schechner, using Goffman's words, argues that the events on stage must be experienced as, what he deems, ‘actual realization': meaning that “the reality of performance is in the performing” (Bennet, 1997:11). Because the violence taking place on stage is only a performance, the spectator does not intervene as he might in an actual violence he would see taking place outside the theatre hall. However, that does not, as Schechner puts it, make the violence ‘less real' but ‘different real' (Bennet, 1997:11). The imaginary world of theatre is not an entirely ‘unreal' world, it is a world based on real occurrences. These real occurrences are taken to the imaginary world with hopes that when they are returned to the real world they will impact it in different ways, in ways set to transform it