Gas formation in liquid in initial stages of a pulsed discharge

Gas formation in electrolytes with=10^–2–10^–4–1cm^–1, distilled water = 10^–5-1.5 ·10^{–6 –1}cm^–1, and chemically pure n-hexane in the initial stages of formation of discharge with rectangular voltage pulses of 0.67 and 1.85 sec duration is investigated. The experimental results are compared with the results of approximate calculations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 42–47, November, 1972.The authors thank V. V. Ryumin for taking part in the discussion of the results and V. V. Lopatin for participation in the experiments with electron-optical light amplifier.     

Gluon and quark jets in deep-inelastic scattering of electrons by nucleons

The paper considers the formation of gluon and quark jets in the inelastic scattering of electrons by nucleons with large momentum transfers. It is assumed that these jets are created by the processes e^–+qe^–+q+g and e^–+ g e^–+q+q, where q is a quark and g is a gluon. The angular distributions of gluon and quark jets are calculated in the lowest order in the quark-gluon coupling constant. It is shown that after integration the processes e^–+qe^–+q+g and e^–+g e^–+q+¯q lead to violation of the scaling invariance of deep-inelastic scattering of electrons by nucleons.Translated from Izvestiya Vysshkikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 68–73, September, 1981.     

An IR-Radiometer with Internal Signal Modulation

An infrared (IR) radiometer electrical circuit on the basis of photoresistors and photodiodes made of silicon doped with zinc (Si) as well as the narrow bandgap semiconductor alloy Pb_0.78Sn_0.22Te is presented. In the circuit suggested a bridge with the photoreceiver connected to the radiometer input and immediately fed by signal generators functions as a radiation modulator. The threshold sensitivity turned out on a recorder is 2·10^–13 W·Hz^–1/2 (for the n⁺–n–n⁺ structures made of Si, =0.8–l.2m, T=300K); 1.4·10^–15W·Hz^–1/2 (for p⁺–n–n⁺ S-diodes on the basis of Si, =0.8–1.2m, T=300K) and 10^–12W·Hz^1/2 (for photodiodes on the basis of Pb_0.78Sn_0.22Te, =8–13m, T=77K).     

Electrical properties of p-type ZnGeP2 irradiated by H+ ions

The properties of p-type ZnGeP₂ [p₀=(5–10)·10¹⁰ cm^–3, ₀=(2–5)·10^–7 (·cm)^–1], irradiated with H⁺ ions [E=5 MeV, T_irr=300 K, D=(1·10¹²–1.7·10¹⁶) cm^–2] are studied. An increase in the resistivity (to gr_max - 5·10¹¹ ·cm) and subsequent reduction in for large currents of H⁺ ions ( - 9·10⁸ ·cm for D - 1.7·10¹⁶ cm^–2), is observed in irradiated crystals. The resistivity of irradiated p-type ZnGeP₂ is found to be very sensitive to hydrostatic pressure [(4–5)·10^–5 bar^–1]. The annealing of radiation defects in the temperature interval (20–600) °C is examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 91–93, October, 1991.     

Estimation of the Optimum Concentration Interval of the Contents of Praseodymium, Neodymium, Europium, Holmium, and Erbium in a Solution

Based on the electronic absorption spectra of Pr³⁺, Nd³⁺, Eu³⁺, Ho³⁺, and Er³⁺ ions in 1 M aqueous solutions of chloric acid, calibration graphs have been constructed in a concentration of metals–optical density of a solution format for different frequencies. The band for praseodymium was used at 22,520 cm^–1, for neodymium at 17,380, 13,480, and 12,560 cm^–1, for europium at 25,380 cm^–1, for holmium at 18,580 and 15,580 cm^–1, and for erbium at 39,160, 26,480, and 19,160 cm^–1. The errors in determining the concentration of the indicated elements as a function of their content have been calculated. It is shown that for perchloric solutions of praseodymium it is possible to correctly determine its contents within the concentration range 0.1–1.5% at a frequency of 22,520 cm^–1; for neodymium the ranges are 0.4–1.0, 0.3–1.0, and 0.5–1.0% at 17,380, 13,480, and 12,560 cm^–1, respectively; for europium 0.4–1.5% at 25,380 cm^–1; for holmium — 0.2–1.5 and 0.4–1.5% at 15,580 and 18,580 cm^–1, and for erbium the range is 0.4–1.0% at frequencies of 39,160, 26,480, and 19,160 cm^–1.     

Supertransferred hyperfine interaction in magnetic insulators (II)

The important mechanisms of supertransferred hyperfine (STHF) interactions in N–O–M chains are briefly discussed: (i) spin polarization ofns states in the N-ion due to the s-d exchange interaction,H _STHF ^sd ; (ii) contributions of spin-polarized states of the intervening O-ion,H _STHF ^II ; (iii) transfer of d-electrons of the M-ion to emptyns states in the N-ion,H _STHF ^III . The dependence ofH _STHF upon the N–O–M bond configuration, electronic structure, and orbital state of the M-ion is presented in a convenient form. The STHF interactions in the chains Sn⁴⁺–O^2––Fe³⁺, Cr³⁺ in compounds with slightly distorted Perovskite structure are considered. The STHF field in the chain Sn⁴⁺–O^2––Cr³⁺ is shown to change the sign within the range of angles near 170°. This conclusion is in line with published data on the isoelectronic chain Sn⁴⁺–O²–Mn⁴⁺ in the compounds Ca_1–x Sr _x MnO₃. The results obtained for the N–O–Fe³⁺ chain are rationalized by the predicted angular dependence ofH _STHF=+ cos + cos². Features of the STHF interactions in N–O–M chains with an M-ion in an orbital degenerate state are examplified by a preliminary analysis of N–O^2––V³⁺ chains in orthovanadites.     

IR Reflection of Thin Bi4Ge3O12 Films

The spectra of IR reflection of the systems thin Bi₄Ge₃O₁₂ film–substrate made of molten -SiO₂ quartz in the region 10–1600 cm^–1 at 295 K are investigatedterpretation of fundamental vibrations in the region 10–800 cm^–1 and two phonon processes in the region 800–1600 cm^–1 are considered.     

Positron mobility in anthracene

We have measured the positron mobility in a sample of scintillation grade anthracene at two temperatures. We obtain at 300 K: =(26.0±0.9±2.6) cm²V^–1s^–1 and at 77 K: =(33.4±1.1±3.3) cm²V^–1s^–1, where the first error estimate is statistical and the second is systematic. We have also made preliminary measurements on a highly purified sample that yields =(130±3±20) cm² V^–1 s^–1 at 300 K. The data are consistent with the hypothesis that the positron is scattered from both impurities and acoustic phonons in the first sample, and predominantly from photons in the second. It appears that positrons in pure anthracene crystals are delocalized and have a mean free path of about 85 Å at room temperature.     

Generation of picosecond pulses in solid-state lasers using new active media

Results are reported of investigations aimed at generating nanosecond radiation pulses in solid-state lasers using new active media having broad gain lines. Passive mode locking is accomplished for the first time in a BeLa:Nd³⁺ laser at a wavelength 1.354 m, and in a YAG:Nd³⁺ laser on a 1.32–m transition. The free lasing and mode-locking regimes were investigated in an alexandrite (BeAl²O₄:Cr³⁺) laser in the 0.72–0.78–m range and in a synchronously pumped laser on F 2- centers in LiF in the 1.12–1.24–m region. The features of nonlinear perception of IR radiation by the eye, using a developed picosecond laser on F₂ ^– centers, are investigated for the first time.Translated from Lazernye Sistemy, pp. 67–86, 1982.     

Two-proton multiplets in theN=82 nucleus 62 144 Sm82 from in-beamγ-measurements

In a high sensitivity (,2n) in-beam study of ₆₂ ¹⁴⁴ Sm₈₂, with the Kölner Würfel OSIRIS -detector array including a Compton polarimeter, we have identified the complete two-proton multiplets d ₅ ^2/–2 , d ₅ ^2/–1 g ₇ ^2/–1 , g ₇ ^2/–2 , h_11/2d ₅ ^2/–1 and the 9^– to 4^– members of the h_11·/2g ₇ ^2/–1 multiplet.Work partially supported by CICYT (Spain).     

Negative muon hyperfine transition rate in aluminum

The residual polarization of theF ^– hyperfine state of ^–27Al has been investigated as a function of applied transverse magnetic field strength using standard TD- ^–SR techniques. TheF ^– precession frequency is –0.2623(5) [theoretical value: –0.2622] times that of the free muon in the same field. The observed muon decay electron asymmetry in theF ^– state decreases with increasing magnetic field strength, due to initial precession in the opposite direction of theF ⁺ state, which most muon initially populate, followed by a rapid transition to theF ^– state. A fit of the data to this model indicates a transition rateR=41(9)s^–1, in good agreement with theoretical predictions. This method can be used to determineR experimentally in other cases where it is too fast to be observed directly.     

Electric and tensoelectric study of radiation defects in GaAs

The electric and tensoelectric properties are studied for GaAs crystals which have been irradiated by electrons (2.3 Mev) at 300°K with integrated fluxes of up to 2·10¹⁵ –1·10¹⁹ cm^–2. On the basis of the electrical neutrality equation, including seven energy levels (E1–E5, H0, H1) of the radiation defects, the specific resistivity and the strain sensitivity coefficient are quantitatively analyzed as a function of exposure. The pressure coefficients for the E1–E5 levels with respect to the _c ⁶ point are determined to be (0, 9.6, 11.0, 11.6, 11.6)·10^–6 eV/bar, respectively, at 300°K.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 81–87, October, 1986.     

Polarization measurements in high energy elastic scattering of pions,kaons, protons and antiprotons on protons and comparison with regge phenomenology

The polarization parameterP has been measured for elastic scattering on polarized protons, of ^–, K^– and ¯p at 40 GeV/c and of ⁺, K⁺ and p at 45 GeV/c. Four-momentum transfer ranges from –0·08 to –1·8 (GeV/c)² for ^–p, and from –0·08 to about –1sd0(GeV/c)² for p, ⁺, K^± and ¯p.The angular distribution of the polarization in ^–p exhibits the well known non sense double zero att=–0·6 (GeV/c)². The K^–p and ¯pp results are compatible with exchange degeneracy for ¦t¦_r <0·5 (GeV/c)². The energy dependence of the polarizationP(t) in ^–p and in K⁺p above 10 GeV/c incident momentum is compatible with interference between Pomeron and Regge poles. On the contrary, the polarization in pp elastic scattering decreases faster than ordinary Regge model predictions. This result can be explained by interference between non flip and flip amplitudes of the Pomeron, leading to negative values for the polarization.Presented by A.de Lesquen at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.     

Energy spectrum and angular distribution of muons from the decay of heavy leptons produced in colliding electron-positron beams

On the basis of an arbitrary (V, A) structure of the neutral weak ¯ee and LL currents (L=^–, M⁰) a study is made of the processes of production in colliding electron-positron beams of pairs of heavy leptons with subsequent decays in accordance with the schemes e⁺e^––(µ^–v_µv) + ⁺( anything) and e⁺e^–M⁰(µ^–e⁺v_e) + M⁰( anything). The energy spectrum and asymmetry of the distribution of the produced muons are investigated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 66–70, February, 1981.     

Redox reaction of μ−O in water determined by the chemical shift

The chemical shift of ^–O in water, ice and in aqueous hydrogen peroxide (H₂O₂) was examined using ^–O resonance. Two distinct signals are obtained in water and ice. Using ⁺ resonance signal as a standard, the observed shiftsg are –7.0×10^–4 (signal A) and –12.1×10^–4 (signal B) respectively. The intensity of the two fractions are almost equivalent in water; however, in ice, the intensity of signal B decreases with increase of signal A. After the addition of hydrogen peroxide to the water signal B disappears, A increases, and the total amplitude is increased.     

Correlation function of A γ-γ cascade (0.34 MeV–1.38 MeV) on49Ti

The angular correlations of a cascade of capture gamma rays with energies of E₁=0.34 MeV, E₂=1.38 MeV on⁴⁹Ti nuclei have been measured. The results confirm that it is a cascade of the type 1/2^– (M1+E2) 3/2^– (E2) 7/2^– with a mixing parameter of the first transition =–0.1, or =+2.2.     

Properties of MOS-structures based on anode-oxidized CdSnAs2

The properties of metal (Al, Au)-anodic oxide-CdSnAs₂ monocrystal structures are studied. It is established that MOS-structures using undoped CdSnAs₂ crystals show a high positive fixed charge in the anodic oxide (N_S 5·10¹² cm^–2) and high surface state density on the oxide-CdSnAs₂ boundary surface (N_SS 2·10¹³ cm^–2·eV^–1). In MOS-structures using diffusion-doped (copper) crystals the sign of the fixed charge is negative (N_S 10¹¹ cm^–2, N_SS 2·10¹² cm^–2·eV^–1). The latter structures show a definite photosensitivity and photomemory. The possibility of effective control of the fixed charge value within the oxide by illumination is shown. The surface state distribution over energy, time constant, and capture section is determined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 90–93, September, 1982.     

Do We Really Need Cold Dark Matter?

It is shown that a negative cosmological constant –10^–56 cm^–2 can completely replace cold dark matter in galaxy clusters. The consequences of such a constant are discussed.