Reliability a 2-way linear consecutively connected system with multistate components

A 2-way linear consecutively-connected system with multistate components (2-way LCCSMC) consists of linearly ordered components e_i, iε[0,n+1]. e₀, can send a signal only in forward direction, each e_i, iε[1,n], is capable to send it in both directions, e_n+1, can send it only in backward direction. All components are capable to receive a signal.The component e_i is in state (h,k), hε[0,i], kε[0,n+1−i], iε[0,n+1], if it sends a signal directly to h components immediately preceding e_i and k components immediately following e_i. e₀ and e_n+1 can only be in states (0,·) and (·,0), respectively. The probability that e_i is in state (h,k) is assumed to be known for each admissible h and k. The states of all components are mutually s-independent. The 2-way LCCSMC is operating iff a signal is transmitted forward, from e₀ to e_n+1, and backward, from e_n+1 to e₀, possibly indirectly via intermediate components e₁, … ,e_n. The paper gives an algorithm for determining the 2-way LCCSMC reliability.     

Reconstruction of dependences of the tunneling current on the oxide voltage using the dynamic current-voltage characteristics of the n +-Si-SiO2- n -Si heterostructures

Precision measurements of dynamic current-voltage characteristics of an Al-n ⁺-Si-SiO₂-n-Si structure with a thin (<50 ?) oxide make it possible to separate the active (I _a ) and capacitive (I _c ) components from the total current. An algorithm for the analysis of the capacitive component is developed; this algorithm makes it possible to determine in a single experiment the doping level of n-Si, the oxide capacitance C _i , and also the density and sign of the charge fixed in the oxide. Dependences of the surface potential in n-Si and the voltage drop across the oxide on the gate potential V _g in the transverse electric fields |F| ≤ 10 MV/cm were calculated based on the above data without using any adjustable parameters. At maximum values of |F|, the sheet density of electrons (holes) in n-Si does not exceed 10¹³ cm⁻², which is indicative of the degeneracy and size quantization of electron gas. The dependences I _t (V _g ) and V _i (V _g ) were used to recover the current-voltage characteristics of the tunneling current I _t (V _i ) ≡ I _a (V _i ); these characteristics were measured within more than ten orders of magnitude of their range of variation in the conditions of both the enhancement of the n-Si surface and the inversion. The observed I _t (V _i ) characteristics are not quantitatively described in the context of existing concepts of the tunnel effect. Original Russian Text ? A.G. Zhdan, N.F. Kukharskaya, V.G. Naryshkina, G.V. Chucheva, 2007, published in Fizika i Tekhnika Poluprovodnikov, 2007, Vol. 41, No. 9, pp. 1135–1142.     

Specific features of the temperature dependence of the conduction electron concentration in the narrow-gap and zero-gap states of Cd<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Hg<Subscript>1 − <Emphasis Type="Italic">x</Emphasis></Subscript>Te

Results of studies of the conductivity σ and the Hall coefficient R in the Cd _x Hg_{1 − x} Te crystals with x = 0.1, 0.12, 0.14, and 0.15 are analyzed in the temperature range T = 4.2–300 K and the magnetic field range B = 0.005–2.22 T. Using data on the R(B) in low and high magnetic fields and the data on σ(T), electron and hole concentrations and mobilities are determined. It is shown that the electron concentration n in the studied samples is almost independent of T in the range 4.2–15 K, while as T increases, it increases according to the law n ∝ T ^r (r > 3/2), where r = f(n, T, x). It is found that r varies from 1.7 at x = 0.1 to 3.1 at compositions with x = 0.14 and 0.15. The results for n(T) are compared with theory, taking into account nonparabolicity of the variance law for ⃛(T), and with the theory of impurity states in narrow-gap and zero-gap semiconductors. It is shown that the constancy of n(T) up to ∼15 K and the strong dependence n(T) (r > 3/2) at higher temperatures are caused by the intense ionization of electrons localized at acceptor states.     

A numerical method for calculation of transients in electric circuits

 The present paper describes a numerical method for calculation of transients in electric circuits,using a step by step approach.For a small interval of time △t=const,for each branch j of circuit one calculates α_j=R_j+L_j/△t+△t/C_j,β_j=R_j+△t/C_j and θ=△t/C_j.After that,for each interval △t the current increments △i_(jk),the currents i_(jk)=i_(jk-1)+△i_(jk)and the capacitor\'s voltage u_(cjk)=u_(cjk-1)+Au_(cjk)are calculated. The values of △i_(jk)are the roots of a system of simultaneous linear equations.The results of numerical calculation of transients by the proposed method do not differ from those obtained by analytical ones.The proposed method can be applied to a large number of problems in electrical engineering.A similar approach can be used for the calculation of transients in non-linear electric circuits and in other engineering disciplines(mechanics,thermodynamics,hydraulics etc.).Several numerical examples show how the pro- posed method can be applied.     

Dispersion characteristics of the Hm,n and Em,n modes in a multilayer metal-dielectric waveguide

Dispersion equations for the H _m,n and E _m,n modes in a three-layer metal-dielectric waveguide with odd and even field variations over the thickness of two basic layers are analyzed analytically and numerically. For the first time, the effects of interaction between even cophasal H _n ^s modes and antiphase H _n ^p modes in the double-thickness basic layer and the odd E _m ^s and E _m ^p modes in the single-thickness basic layer are found. The realizability of high-power microwave power dividers on the basis of the considered waveguides is shown.     

On the maximum thickness of the space-charge region of reverse biased <Emphasis Type="Italic">p</Emphasis><Superscript>+</Superscript>-<Emphasis Type="Italic">n</Emphasis> junctions with a positive bevel

Two-dimensional potential and electric-field strength distributions in edge regions of sharply asymmetric reverse biased p ⁺-n junctions with a positive bevel were numerically simulated. It was shown that the maximum thickness of the space-charge region W _nM nonmonotonically depends on the angle θ between the bevel surface and junction plane: the function W _nM (θ) reaches a maximum at θ decreasing from 60° to 35° as the parameter Q _s /ɛ _s ɛ₀ EvM increases from 0 to 0.02 (here Q _s is the surface charge density, ɛ _s ɛ₀ is the absolute permittivity of the semiconductor, and E _vM is the maximum field strength in the space-charge region of the p ⁺-n junction far from the bevel). The results obtained may be useful in designing high-voltage thyristors based on Si, SiC, and other materials.     

Book

Book Reviews in this article: 'Tis the season Mass Media and American Politics by Doris A. Graber. Washington, D.C.: Congressional Quarterly Inc., 1980. 304 pages. Politics as Communication by Robert G. Meadow. Norwood, N. J.: Ablex Pub lishing Company, 1980. 269 pages. The Great Debates: Carter vs. Ford 1976 edited by Sidney Kraus. Bloomington, Ind.: Indiana University Press, 1979. 553 pages. Carter us. Ford: The Counterfeit Debates of 1976 by Lloyd Bitzer and Theodore Rueter. Madison, Wisc.: University of Wisconsin Press, 1980. 428 pages. Ambitious analysis The MOSS Media Eledion: How Americans Choose Their President by Thomas E. Patterson. University of California San Diego Renewing a tradition Social Theories of the Press: Early Cerman and American Perspectioes by Hanno Hardt. Boston College A good start Evaluation: A Systematic Approach University of Hawaii Naturalistic approach The Television Erperience: what Children See by Mariann Pezzella Winick and Charles Winick. Say good night, Gracie Don't Touch That Diall: Radio Programming in American Life, 1920–1960 by J. Fred MacDonald. An emerging discipline Readings in Consumer Behavior: Zndividuals, Gmps and Organizations edited by Melanie Wallendorf and Gerald Zaltman. University of Iowa A vital agenda Friendly Fascism: The New Face of Power in America by Bertram Gross. University of California. San Diego Scholar1y Marxism Multinational Corporations and the Contsol of Culture: The Ideological Apparatuses of Imperialism by Armand Mattelart. Saint Mary's College of California All about “All in the Family” All in the Family: A Critical Appraisal edited by Richard P. Adler. University of Washington Worth the wait The Signs of Language by Edward S. Klima and Ursula Bellugi. University of Chicago Critical linguistics Language as Ideology by Gunther Kress and Robert Hodge. Queens College City University of New York Scattered insights Nonverbal Behavior: Applications and Cultural Implications edited by Aaron Wolfgang. University of Windsor Intelligent overview American Communication in a Global Sociecy by Glen Fisher. Northern Illinois University The SECAM story The Politics of Intenatcional Standards: France and the Color TV War by Rhonda J. Crane.     

An Efficient Existentially Unforgeable Signature Scheme and Its Applications

A signature scheme is existentially unforgeable if, given any polynomial (in the security parameter) number of pairs (m ₁ , S(m ₁ )), (m ₂ , S(m ₂ )), . . ., (m _k , S(m _k )), where S(m) denotes the signature on the message m , it is computationally infeasible to generate a pair (m _k+1 , S(m _k+1 )) for any message m _k+1 {m ₁ , . . ., m _k } . We present an existentially unforgeable signature scheme that for a reasonable setting of parameters requires at most six times the amount of time needed to generate a signature using ``plain' RSA (which is not existentially unforgeable). We point out applications where our scheme is desirable. Received 2 May 1995 and revised 10 July 1997     

Book

Book reviews in this article: Family feud Electronic Democracy: Television's Impact on the American Political Process by Anne Rawley Saldich. Radical conscience Something to Guard: The Stormy Life of the “National Guardian,” 1948–1967 by Cedric Belfrage and James Aronson. University of Pennsylvania Phonic form The Sound Shape of Language by Roman Jakobson and Linda R. Waugh. Australian media scene Reflections of Reality: The Media in Australia by Trevor Barr. Australia's Media Monopolies by Humphrey McQueen. Small Screen, Big Business: The Great Australian TV Robbery by Susan Kippax and John P. Murray. Northern Illinois University Marxian analysis Communication and Class Struggle, Volume 1: Capitalism, Imperialism edited by Armand Mattelart and Seth Siegelaub. Queens College City University of New York Bull session supremacy? Education's Lasting Influence on Values by Herbert H. Hyman and Charles R. Wright. Texas Tech University A moral dimension From the Other Point of View by J. Daniel Hess. The Univetsity of Texas at Austin Judicious scholarship Who Owns the Media?: Concentration of Ownership in the Mass Communications Industry edited by Benjamin M. Compaine. Iowa State University Difficult task The News From Southeast Asia: The Sociology of Newsmaking by Rodney Tiffen. University of Minnesota Just a duncin' fool To Dance Is Human: A Theoy of Nonverbal Communication by Judith Lynne Hanna. University of California San Francisco Strong analysis The British Press: A Manifesto edited by James Curran. Rutgers University The Organization of styles Photographers At Work: A Sociology of Photographic Styles by Barbara Rosenblum. University of California at Davis Asian priorities Communication Strategies for Productivity Improvement by Florangel Rosario-Braid. University of Hawaii Australian insight The Politics of the Press by Patricia Edgar. Capricrnia Institute of Advanced Education Rockhampton, Australia A personal look Inside ABC: American Broadcasting Company's Rise to Power by Sterling Quinlan. University of Louisville Third World media Media and the Third World by D. R. Mankekar. UNESCO and the Third World Media: An Appraisal. Lombard Associates, Inc. New York City Guidelines on TV debates With the Nation Watching. Report of the Twentieth Century Fund Task Force on Televised Presidential Debates. With a Background Paper by Lee M. Mitchell. Rutgers University Pioneering attempt Cognitive Styles in Law Schools by Alfred G. Smith. National Telecommunications and Information Administration Debatable assumptions A Free and Balanced Flow. Report of the Twentieth Century Fund Task Force on the International Flow of News. With a Background Paper by Colin Legum and John Cornwell. Fordham University For selective reading Information Societies: Comparing the Japanese and American Experiences edited by Alex S. Edelstein, John E. Bowes, and Sheldon M. Harsel. Capricornia Institute of Advanced Education Rockhampton, Queensland, Australia Resolving contradictions Nonsense: Aspects of Intertextuality in Folklore and Literature by Susan Stewart. Washington State University Balancing act Mass Media, Freedom of Speech and Advertising: A Study in Communication Law by Daniel M. Rohrer. University of North Carolina Immaculate perception? Hip Capitalism by Susan Krieger. Foreword by James G. March. State University of New York at Buffalo Briefly noted Asian Journalism by Elliot S. Parker and Emelia M. Parker. The Habima—Israel's National Theater by Emanuel Levy. Language and Control by Roger Fowler, Bob Hodge, Gunther Kress, and Tony Trew. Teaching Ethics in Journalism Education by Clifford G. Christians and Catherine L. Covert. The Celluloid Persuasion by Lawrence Murray.     

Self-compensation in CdTe〈Cl〉 in the presence of phase equilibrium of the system crystal-cadmium (tellurium) vapor

The self-compensation of charged point defects in CdTe〈Cl〉 is investigated down to the lower limit of free-carrier densities (n _i ,p _i ) over the entire range of vapor pressures P _Cd and P _Te in equilibrium of the crystal-gas phases during annealing. Under conditions where P _Te2 is controlled during annealing of the crystal, the electron density n is observed to increase from 10⁷ cm⁻³ to 10¹⁴ cm⁻³ as P _Te increases from P _min to CdTe〈Te〉 saturation. This result is attributed to the formation of a Te_Cd antistructural defect. The appearance of Te_Cd in the crystal lowers the concentration of cadmium vacancies to the point that the mechanism of exact self-compensation of CdTe〈Cl〉 is disrupted, and low-resistivity n-type crystals are obtained. The data obtained on the concentration p(n) as a function of P _Te2 is used to plot the total n-n _i -p _i dependence with the variation of P _Cd-P _Te2, reflecting the state of point defects in CdTe〈Te〉. The procedure for annealing crystals in two-phase crystal-gas equilibrium is used to reversibly induce n _i -p _i inversion of the electrical conductivity of the crystal. Fiz. Tekh. Poluprovodn. 32, 159–163 (February 1998)     

Degradation fitting of irradiated solar cells using variable threshold energy for atomic displacement

Characteristic degradation curves for proton and electron induced degradation of triple junction (3J) and isotype Ga_0.5In_0.5P/GaAs/Ge solar cells were obtained. The displacement damage dose methodology in combination with a varying effective threshold energy for atomic displacement T _{d ,e f f} was used to analyze 3G28 and 3G30 3J cell data. The nonionizing energy loss (NIEL) was calculated analytically, and T _{d ,e f f} was explicitly introduced as a fit parameter. Using the GaAs NIEL in fitting the 3J degradation data, a T _{d ,e f f} of 21 eV was determined, whereas a T _{d ,e f f} of 36 eV was found using the Ga_0.5In_0.5P NIEL. In GaAs and Ga_0.5In_0.5P single junction cells, the effective threshold energies for atomic displacement of 22 and 34 eV were determined. Copyright © 2017 John Wiley & Sons, Ltd.     

Books

Book reviews in this article: Clear indictment Broadcasting in the United States: Innovative Challenge and Organizational Control by Vincent Mosco. Superficial treatment A Crisis for the American Press by John Hohenberg. Improved collection Television: The Critical View (second edition) edited by Horace Newcomb. User's guide The Use of Radio in Social Development by Terry D. Peigh, Martin J. Maloney, Robert C. Higgins, and Donald J. Bogue. Undelivered promises Freedom of Speech and Human Rights: An International Perspective by Daniel M. Rohrer. No joke Understanding Laughter: The Workings of Wit and Humor by Charles R. Gruner. The surest path Television Violence and the Adolescent Boy by William A. Belson. Profound distrust The Third World and Press Freedom edited by Philip C. Horton. Collective behavior Crowds and Riots: A Study in Social Organization by Sam Wright. Examining ethnicity Interethnic Communication edited by E. Lamar Ross. Contemporary dilemmas Opening and Closing: Strategies of Information Adaptation in Society by Orrin E. Klapp. Artfully articulated On the Margins of Discourse: The Relation of Literature to Language by Barbara Herrnstein Smith. “Scholarly sampler” Inter/Media: Interpersonal Communication in a Media World edited by Gary Gumpert and Robert Cathcart. No punches pulled Communications for a Mobile Society. An Assessment of New Technology by Raymond Bowers, Alfred M. Lee, and Cary Hershey. Understanding culture The Cultural Dialogue: An Introduction to Intercultural Communication by Michael H. Prosser. Research controversies Television Network News: Issues in Content Research edited by William Adams and Fay Schreibman. Something for everyone Intercultural and International Communication edited by Fred L. Casmir. Introduction to Jakobson Six Lectures on Sound and Meaning by Roman Jakobson. Sound if selective Deviance and Mass Media edited by Charles Winick. Looking at looking A Paradigm for Looking—Cross-Cultural Research with Visual Media by Beryl L. Bellman and Bennetta Jules-Rosette. Monitoring the marketplace Telecommunications Policy and the Citizen: Public Interest Perspectives on the Communications Act Rewrite edited by Timothy R. Haight.     

Qualitative analysis of motion properties of semistate models of large-scale systems

This paper studies the behavior of motions of large-scale (LS) semistate systems (SSS) governed byP _i (t)x _i =M _i (t,x _i )x _i +f _i (t)+h _i (t, x), i=1,2,...,s, =(x ₁ ^T x ₂ ^T x _s ^T )^T, where matricesP _i (t) are singular. Using Lyapunov's approach and the tools for LS system analysis, a variant of attractivity and ultimate boundedness of appropriate time-variable sets are investigated. The results are based on a specific choice of the aggregate functions. It is assumed that the reduction of equations to a normal form of lower order is inconvenient. The aggregation-decomposition approach used in this paper reduces the dimensionality of an aggregate matrix of the system to the number of its systems. Motion properties of LS systems are deduced from the properties of its isolated subsystems, the character of interconnections, and the conditions imposed on the system aggregate matrix. Sufficient algebraic conditions for the above-mentioned motion properties are developed.     

A new mathematical approach to multi-area power system reliability evaluation

In the original interconnected system reliability model the system state space consists of a set of all n-tuples X = (x₁, x₂,…, x_l, x_l+1,…, x_n) where x₁, x₂, x₃,…, x_l are generation capacities and x_l+1, …, x_n are intertie capacities. Corresponding to each load state i we have state space S_i. For each S_i there exists a map F_i:S_i → R. For each i, S_i is then decomposed into sets of acceptable states A_ks and sets of unacceptable states B_ls. Each B_l is then classified accordingly as it is a loss of load in a particular area or not. Then the appropriate reliability indices are calculated. In this approach the maximal flow function is viewed as a map F: _iS_i → R. It is shown that F is a piecewise linear function. It is also shown that there is a one-one correspondence between B sets with the same area loss of load to each of the linear functions. A useful result which aids in the reduction of computational time of frequency calculation of loss of load is then derived.     

Hole boil-off and the magnetoresitance of the semimagnetic semiconductor Hg1−x MnxTe1−y Sey

Galvanomagnetic effects were investigated in gapless and narrow-gap semiconductors of the form Hg_1−x Mn_xTe_1−y Se_y with x=0.03–0.11, y=0.01–0.10 (−150<ɛ _g <190)meV and acceptor concentration 5.4×10¹⁶<N _A <4.3×10¹⁸ cm⁻³. In magnetic fields H=5–50 kOe and at T=1.3–4.2 K, the observed hole concentration p=1/eR was found to increase by a substantial factor (of up to 500). This was accompanied by a fall in the longitudinal (ρ _zz ) and transverse (ρ _xx ) magnetoresistivities. The hole “boil-off” is assumed to be a consequence of the existence at H=0 of a bound magnetic polaron and the delocalization of carriers when these states are destroyed by the external magnetic field. The anomalous ratio of longitudinal-to-transverse resistivities (ρ _zz >ρ _xx ), observed at liquid-helium temperatures and in magnetic fields H>10 kOe, is explained in terms of the properties of the energy spectrum of the valence band of semimagnetic semiconductors in quantizing magnetic fields. Fiz. Tekh. Poluprovodn. 31, 1198–1205 (October 1997)     

A high‐performance switch architecture based on mesh of trees

With emergence of various new Internet‐enabled devices, such as tablet PCs or smart phones along with their own applications, the traffic growth rate is getting faster and faster these days and demands more communication bandwidth at even faster rate than before. To accommodate this ever‐increasing network traffic, even faster Internet routers are required. To respond for these needs, we propose a new mesh of trees based switch architecture, called MOTS(N) switch. In addition, we also propose two more variations of MOTS(N) to further improve it. MOTS(N) is inspired by crossbar with crosspoint buffers. It forms a binary tree for each output line, where each gridpoint buffer ? ? Because the fabric of MOTS(N) switch is not pure crossbar, we call the buffers in the same location in pure crossbar gridpoint buffers. Details will be presented in the following sections.
is a leaf node and each internal node is 2‐in 1‐out merge buffer § § 2‐in 1‐out merge buffer can accommodate two memory writes and one memory read simultaneously by using its modularized architecture 31 .
emulating FIFO queues. Because of this FIFO characteristic of internal buffers, MOTS(N) ensures QoS like FIFO output‐queued switch. The root node of the tree for each output line is the only component connected to the output port where each cell is transmitted to output port without any contention. To limit the number of buffers in MOTS(N) switch, we present one of its improved (practical) variations, IMOTS(N) switch, as well. For IMOTS(N) switch architecture, sizes of the buffers in the fabric are limited by a certain amount. As a downside of IMOTS(N), however, every cell should go through log ₂N + 1 number of buffers in the fabric to be transmitted to the designated output line. Therefore, for even further improvement, IMOTS(N) with cut‐through, denoted as IMOTS‐CT(N), is also proposed in this paper. In IMOTS‐CT(N) switch, the cells can cut through one or more empty buffers to be transferred from inputs to outputs with simple 1 or 2 bit signal exchanges between buffers. We analyze the throughput of MOTS(N), IMOTS(N), and IMOTS‐CT(N) switches and show that they can achieve 100% throughput under Bernoulli independent and identically distributed uniform traffic. Our quantitative simulation results validate the theoretical analysis. Copyright © 2012 John Wiley & Sons, Ltd.     

On the extraction of the source and drain series resistances of MOSFETs

This article reviews and scrutinizes various proposed methods to extract the individual values of drain and source resistances (R_D and R_S) of MOSFETs, which are important device parameters for modeling and circuit simulation. In general, these methods contain three basic steps: (1) the extraction of the total drain and source resistance (R_D+R_S); (2) the extraction of the difference between the drain and the source resistances (R_D−R_S); and (3) the calculation of R_D and R_S from the knowledge of (R_D+R_S) and (R_D−R_S). These methods are tested and compared in the environments of circuit simulator, device simulation and measurements.     

Determination of the exciton energy from electron beam excited luminescence in direct gap semiconductors

The exciton radiative recombination spectra of CuCl, ZnSe, CuGaS₂ and AgGaSe₂ have been investigated at 300 K. The sample was excited by electron beams of different energies. The reabsorption is determined by the ratio η of the spectra obtained for different electron beam energies such as 5 and 40 kV. This ratio is independant of hv when the absorption coefficient α is small (< 10³cm⁻¹). It increases when α becomes larger than the inverse of the penetration depth ( 3 μ) of the 40 kV electron beam. In this case, η is approximately proportional to the absorption coefficient. In particular, its maxima give the excitonic energies E_ex. We find the following values, in agreement with previous reflectivity and absorption measurements: for CuCl, E_ex(Z₃) = 3.26 eV and E_ex(Z₁₂) = 3.33 eV: for ZnSe, E_ex = 2.70 eV; for CuGaS₂, E_ex(A) = 2.46 eV and E_ex(B) = 2.59 eV. In the case of AgGaSe₂, there is no peak in the η spectrum and we have fitted our data to a broadened exciton model. We obtain E_ex(A) = 1.80 eV.     

Integrally Small Perturbations of Linear Nonautonomous Systems

Let A(t) and B(t) (t≥0) be variable n×n-matrices. Assuming that the system [(x)\dot]=A(t)x\dot{x}=A(t)x is exponentially stable and the matrix norm of the integral ò₀^t (B(s)-A(s)) ds\int_{0}^{t} (B(s)-A(s))\,ds is sufficiently small, for the system [(x)\dot]=B(t)x\dot{x}=B(t)x we derive explicit stability conditions, which improve the well-known ones in appropriate situations. The results are illustrated by a numerical example.     

Properties of deep Cu levels in GaP

Optical properties of two Cu-induced deep acceptorlike levels in GaP with binding energies E_A = 0.50 ± 0.01 eV and E_B 0.7 eV have been investigated. Data are reported here from purely optical techniques, based on detection of photoluminescence. A detailed spectral analysis of the broad Cu-related 1.65 eV-emission reveals a moderate Frank-Condon shift Δ_FC 105 ± 15 meV for the A-center. Accurate spectral data for optical cross section σ_pA⁰(hν) and σ_nA⁰(hν) were measured for the 0.50 eV A-center. Optical cross sections σ_pB⁰(hν) and σ_nB⁰(hν) could also be measured via luminescence, in spite of the fact that the B-center appears to have a completely nonradiative recombination.