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Two new scaffold-like metal-organic coordination polymers, [Zn2ndc2bpe]·DMF and [Zn2ndc2dedpbp] ·4DMF (ndc is 2,6-naphthalenedicarboxylate, bpe is trans-bis(4-pyridyl)ethylene, and dedpbp is 4,4′-diethynyl-4″,4′″-dipyridylbiphenyl), were synthesized by heating stoichiometric amounts of zinc(II) nitrate, H2ndc, and bpe or dedpbp in DMF. The structures of the polymers were established by X-ray diffraction. Coordination of linear dicarboxylate ligands to zinc cations gives rise to planar square-grid networks, and additional coordination of the bifunctional nitrogen-containing ligands results in the formation of scaffold-like triply interpenetrating structures with a primitive cubic topology.

Development of new means and methods of cerebral temperature monitoring is an actual problem due to the fact that severity and outcomes of diseases in patients with brain damages (strokes, a head trauma) in big degree depend on development of neurogenetic fever and a local cerebral hyperthermia. The temperature monitoring, which is carried out by the implanted sensors, is applied in neurosurgical patients and is practically not used in patients with disorders of cerebral bloodflow. In this regard, noninvasive techniques of brain temperature registration are developing: proton nuclear magnetic resonance spectroscopy and registration of own electromagnetic radiation (EMR) at the high range of frequencies (microwave). The main objective of the study was to define of diagnostic opportunities of noninvasive temperature measurement of brain by means of microwave radiothermometry.

High-power field-effect transistors (FETs) are among the main applications of heterostructures based on group III metal nitrides, which in most cases implement the classical GaN/AlGaN structure with a single junction. An alternative approach based on the use of double heterostructures with imporved two-dimensional electron gas (2DEG) confinement offers a number of advantages, but such structures are usually characterized by a lower carrier mobility and density (in GaN layers of reduced thickness) as compared to the values in the single-junction structures. Optimization of the heterostructure design and ammonia MBE growth conditions allowed us to obtain multilayer AlN/AlGaN/GaN/AlGaN heterostructures with quantum wells, which are characterized by a 2DEG carrier mobility of 1100–1300 cm2/(V s) and a sheet electron density of (1.1–1.3) × 1013 cm-2. Experimental FETs based on the obtained multilayer heterostructures in a static regime exhibit working current densities up to 0.6 A/mm at a transconductance of up to 150 mS/mm and a breakdown voltage above 100 V.

We have studied the effect of two detoxifying factors on aqueous solutions of phenol: UV radiation from different sources, and humic substances. The phenol photoconversion processes were monitored by the fluorescent method; the toxicity of the phenol solutions was monitored using a bioluminescence test. It was shown that effective detoxification of an aqueous phenol solution occurs as a result of addition of humic substances; the most effective photoinduced detoxification was detected when using UV radiation from an exciplex lamp (λrad = 308 nm). Other UV irradiation sources and the combined action of UV irradiation and humic substances are characterized by a smaller detoxifying effect. In this case, irradiation using an exciplex lamp (λrad = 222 nm) increases the toxicity of the phenol solution both in the presence and in the absence of humic substances.

Seven copper(II) bis-chelates derived from novel sterically hindered ligands — methoxy-β-diketones

Data of influence of the average monthly temperatures and monthly precipitation total on productivity of winter wheat in the Lugansk region for 60 years are presented. The atmospheric temperature and precipitation have decisive importance in dynamics of the winter wheat’s crop-producing power.

The temperature-concentration dependence of the dc electrical conductivity of glasses in the xAg2O-(1 − x)B2O3 (0.05 ≤ x ≤ 0.25) system is investigated using active (amalgam) electrodes. A series of glasses are synthesized with the use of D2O as an isotope tracer. The analysis of data on the electrolysis of glasses at 0.15 ≤ x ≤ 0.225 demonstrates that charge carriers in these glasses involve protons formed upon dissociation of impurity water. The water content is evaluated by IR spectroscopy. The electronic component of the total electrical conductivity is determined by the Liang-Wagner technique. It is shown that the contribution of the electronic component does not exceed the sensitivity of the technique (10−2—10−3%). The participation of silver ions in electricity transport processes is studied by the Hittorf method. It is demonstrated that their transport numbers do not exceed 0.53. A comparison of the physicochemical properties of glasses in the Ag2O-B2O3 and Na2O-B2O3 systems shows that sodium and silver ions occupy different positions in the structure.

The paper contains information on the currently available methods for intensive care for acute myocardial infarction (AMI), by using hyperbaric oxygenation (HBO), antihypoxants, and antioxidants. The presented information is based on the data available in the literature and on the results of the authors’ own studies made in 428 patients with AMI, in whom the time course of changes was determined in blood gas and in the biochemical parameters characterizing energy metabolism and free radical lipid peroxidation. Along with the conventional treatment (thrombolysis, restriction of a necrotic area, myocardial hemodynamic unloading, Labori mixture, anticoagulants, disaggregants, etc.), multimodality therapy for AMI used HBO sessions and antioxidants. The studies have provided evidence that it is possible and expedient to effectively and safely use HBO in AMI. Criteria for selecting the patients to undergo HBO, the time of its use, the choice of barotherapy regimes, and the nature of concomitant therapy are given. The application of the currently available methods for intensive care for hypoxia in AMI (HBO in combination with antihypoxants and antioxidants) can reduce the length of stay at hospital and in resuscitative and intensive care units and considerably decrease mortality rates.

The temperature-concentration dependence of the conductivity in glasses of the system Li2O-P2O5 was studied. The content of extrinsic hydrogen in the structure of glasses was estimated by IR transmission spectra. The effect of hydrogen on the electrical properties and structure of the glasses studied was considered.

The double heterostructure (DHS) high-electron mobility transistor (HEMTs) grown by ammonia molecular beam epitaxy (MBE) is investigated both experimentally and theoretically. The band diagram and the sheet 2D electron concentration are computed, predicting alternating electron and hole slabs to co-exist in the structure. The DC characteristics of the DHS HEMT with the 1 µm gate are measured to asses the device performance. A breakdown threshold up to ∼200 V is demonstrated for the source/drain voltage in DC operation. The parameters of the DHS and conventional AlGaN/GaN single-heterostructure HEMTs are compared. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Two coordination compounds of Zn(II) with a doubly deprotonated bis(β-diketone) 1,3-(CO-CH2-CO-Ph)2Ph (H2L), [Zn2(DMSO)4L2] (I) and [Zn2(bipy)2L2]·4(DMSO) (II) (bipy = 4,4′-bipyridyl; DMSO = dimethylsulfoxide), have been prepared and characterized with XRD method. Both structures are based on a binuclear flat fragment Zn2L2. The crystal structure I reveals van der Waals packing of molecules in which four DMSO ligands are coordinated axially to the cations of the binuclear fragments. The crystal structure II comprises a linear coordination polymer in which adjacent binuclear fragments are connected through bridging bipy ligands to form a molecular ladder type of architecture. Guest DMSO molecules reside in the voids of the crystal packing. The newly obtained host coordination polymer is compared with similar polymers based upon metal dibenzoylmethanate bis-chelate platforms.

The photometric redshifts were derived, based on photometry data in visual and infrared. Deep fields were observed during gamma-ray bursts investigation with the SAO RAS 6-meter telescope (BTA), Spitzer and Hubble Space Telescope. BTA BVRI images were used, as well as F475W, F606W, F814W of ACS at the Hubble Space Telescope and Spitzer IRAC ch1 3.6 μ m, ch3 5.7 μ m. Each BTA BVRI exposure was about one-hour long, reaching objects up to the ~27th stellar magnitude. The GRB 021004 field was investigated. A catalog of 874 discovered objects is being made as well as color diagrams and Hubble diagram for these objects.

A concept for the design of experimental AlGaN/GaN/AlGaN double heterostructures with a two-dimensional electron channel are discussed, together with their main properties. The structures were formed by ammonia molecular-beam epitaxy on sapphire substrates. The foundations for postgrowth technology are developed for microwave field-effect transistors based on Group-III nitrides, including the formation of a mesa isolation and the preparation stage of nonrectifying contacts and the Schottky barrier. The first field-effect transistors fabricated based on the above heterostructures have a complete set of static characteristics and can operate in a mode of weak microwave signals at a frequency of 8.15 GHz.

This article reviews a method of increasing antenna interference suppressor efficiency by dividing the bandwidth of multichannel receiver to narrow sub-bands. Also the principal possibility of the suppression ratio increase on 3-8 dB is proved here. The results of the seminatural experiments made with the use of samples of digitized receiver signal are shown in the article.

Electrical characteristics, namely, the temperature–concentration dependence of the electrical conductivity and the concentration dependence of the transport numbers of lithium ions (determined with the use of the Tubandt method) are investigated for glasses in the Li2SO4–LiPO3 system. It is revealed that only lithium ions are involved in charge transfer. The IR absorption spectra, density, microhardness, and ultrasonic velocity are measured. An analysis of the experimental results obtained demonstrates that SO2-4 ions form terminal groups and can be incorporated into polyphosphate structural fragments. An increase in the electrical conductivity and a decrease in the activation energy for electrical conduction are interpreted in the framework of a crossover of the migration mechanism. In lithium metaphosphate, lithium ions predominantly migrate through the interstitial mechanism. However, an increase in the lithium sulfate content in the initial glass leads to an increase in the fraction of charge carriers that migrate according to the vacancy mechanism.

The activation volumes calculated from the experimental data on the effect exerted by high hydrostatic pressure on the electrical conductivity are compared with the mean fluctuation-microhole volumes calculated from the data on the microhardness of glasses in the Li2O–P2O5 and LiF–LiPO3 systems. The fluctuation-microhole volumes determined from the microhardness are compared with the molar volumes of defects in the structure of glasses. The results obtained indicate that the defect formation occurs according to Frenkel, whereas migration of ions (charge carriers) proceeds predominantly through the interstitial mechanism, which agree with the available data.

The temperature–concentration dependence of the electrical conductivity of glasses in the Li2O–LiPO3 and Li2S–LiPO3 systems is investigated. With the use of the Tubandt method, it is demonstrated that the electric current in glasses of these systems is provided by migration of lithium ions. The concentration dependence of the electrical conductivity is interpreted using the obtained data on the IR absorption spectra, density, microhardness, ultrasonic velocity, etc. It is found that the electrical conductivity of glasses in the Li2S–LiPO3 system is more than 103 times higher than that in pure LiPO3. The observed increase in the electrical conductivity is explained by the formation of sulfur-containing polar structural–chemical groupings of the Li+[S–PO3/2] type, whose dissociation energy is lower than that of similar oxide polar structural fragments. This results in an increase in the number of lithium ions involved in the electricity transport due to an increase in the degree of dissociation of polar structural–chemical units.

The temperature and concentration dependences of the electrical conductivity was studied in Li2S-LiPO3 glasses. The effect of lithium sulfide additions (22.5-25 mol %) to LiPO3 on the electrical conductivity was studied. The nature of the conductivity was studied over the whole range of Li2S concentrations using Tubandt's procedure, and the contribution of electronic component to the total electrical conductivity was examined by Liang-Wagner's polarization method.

The temperature dependence of the electrical conductivity of vitreous lithium, sodium, and potassium metaphosphates is investigated using active electrodes (amalgams of the relevant alkali metals). The decrease in the electrical conductivity in the sequence LiPO3–NaPO3–KPO3 is explained by the fact that the electric current in lithium metaphosphate is carried by lithium ions, whereas the electricity transport in NaPO3 and KPO3 occurs through alkali metal ions together with protons formed upon dissociation of impurity water. The kink observed in the temperature dependence of the electrical conductivity of KPO3 is interpreted in terms of the charge carrier type. It is demonstrated that high-temperature (> 373 K) conduction is provided primarily by migration of potassium ions, whereas low-temperature conduction is due to migration of protons.

The steady-state electrical conductivity of oxychloride glasses in the PbCl2–PbO · B2O3 and PbCl2–2PbO · B2O3 systems is investigated. In the temperature range from ∼190 to ∼380°C, the dependence of logσ on the reciprocal of the temperature exhibits a linear behavior. The nature of charge carriers is studied using the Hittorf technique. It is demonstrated that protons and chlorine ions are charge carriers in solid glasses. The concentration dependence of the transport numbers of chlorine ions is examined by the Tubandt method. The contribution of the electronic component to the total electrical conductivity is estimated with the use of the Liang–Wagner technique. The concentration dependences of the electrical conductivity and the transport numbers of chlorine ions are interpreted in terms of the microinhomogeneous glass structure associated with the selective interaction of components during synthesis of glasses.

A derivative of the metal dibenzoylmethanate (DBM) host type, accomplished through the chemical modification of the DBM ligand, is reported for the first time. The new ligand, (1-naphthoyl)benzoylmethanate (NBM) differs from the parent DBM by an additional phenylene ring. Three new complexes (NiA2(NBM)2), with pyridine (Py), 4-methylpyridine (4-MePy) and 4-phenyl- pyridine (4-PhPy) is A, were synthesized and studied for host properties. Complexes with Py and 4-MePy were isolated as solvent- free forms and did not show any ability to form inclusion compounds with ten solvents tested. Single-crystal XRD study revealed van der Waals type of crystal structure of the complexes. The nickel atom is octahedrally coordinated by two chelating NBMs in the equatorial plane and two terminal pyridines. Naphthyl ligands turn almost perpendicular to the equatorial plane of the complex filling the pocket space which usually accommodates guest species in metal DBM analogues. This 'self-inclusion' of its own frag- ment, that the molecule demonstrates, explains the inability of the complexes to entrap guest solvents. The complex with 4-PhPy forms inclusion compounds with chloroform, benzene, tetrahydrofuran and acetone, the compounds have 1:2 host to guest ratio and are isostructural. A possible explanation of such a difference is the larger size of the pocket which now cannot be completely filled with the naphthyl fragment. # 2003 Elsevier Ltd. All rights reserved.

Activities of the key enzymes of ethanol metabolism were assayed in ethanol-grown cells of an Acinetobacter sp. mutant strain unable to synthesize exopolysaccharides (EPS). The original EPS-producing strain could not be used for enzyme analysis because its cells could not to be separated from the extremely viscous EPS with a high molecular weight. In Acinetobacter sp., ethanol oxidation to acetaldehyde proved to be catalyzed by the NAD+-dependent alcohol dehydrogenase (EC 1.1.1.1.). Both NAD+ and NADP+ could be electron accepters in the acetaldehyde dehydrogenase reaction. Acetate is implicated in the Acinetobacter sp. metabolism via the reaction catalyzed by acetyl-CoA-synthetase (EC 6.2.1.1.). Isocitrate lyase (EC 4.1.3.1.) activity was also detected, indicating that the glyoxylate cycle is the anaplerotic mechanism that replenishes the pool of C4-dicarboxylic acids in Acinetobacter sp. cells. In ethanol metabolism by Acinetobacter sp., the reactions involving acetate are the bottleneck, as evidenced by the inhibitory effect of sodium ions on both acetate oxidation in the intact cells and on acetyl-CoA-synthetase activity in the cell-free extracts, as well as by the limitation of the C2-metabolism by coenzyme A. The results obtained may be helpful in developing a new biotechnological procedure for obtaining ethanol-derived exopolysaccharide ethapolan.

The temperature–concentration dependences of the electrical conductivity and the activation energy for electrical conduction of glasses in the Na2O–B2O3 and Na2O–2PbO · B2O3 systems are studied. The investigation into the nature of the electrical conduction in these glasses reveals that the contribution from the electronic component (10–3%) of the conductivity is within the sensitivity of the Liang–Wagner technique. A considerable alkali conductivity is observed upon introduction of more than ∼12 mol % Na2O. The true transport number of sodium η Na is as large as unity at [Na2O] ≅ 15 mol %. It is shown that the observed temperature–concentration dependences of the electrical and transport properties are governed by the ratio between the concentrations of polar and nonpolar structural–chemical units of the Na+[BO4/2]–, Na+[O–BO2/2] ⇒ Na+[O–BO2/2], Pb2+1/2[BO4/2]–, Pb2+1/2[O–BO2/2], and [BO3/2] types.

The concentration and temperature dependences of the dc electrical conductivity σ of glasses in the PbF2–2PbO · B2O3 system is investigated. It is found that, at 20–25 mol % PbF2, the dependences log σ = f([F]) and Eσ = f([F]) exhibit kinks. The concentration dependence of the true transport number of fluorine ions ηF – is studied using the Tubandt method. It is shown that the introduction of 20–25 mol % PbF2 leads to a crossover from the protonic conductivity to the unipolar fluorine ionic conductivity (\(\eta _{{\text{F}}^{\text{ - }} } = 1.00\)). The results obtained are discussed in terms of the Myuller theory of the microinhomogeneous glass structure associated with the selective interaction of the components during the synthesis.

The steady-state electrical conductivity and microhardness of glasses in the system Na2O-B2O3 was studied. IR spectroscopy was applied to determine the content of impurity hydrogen in the glasses studied.

We report a theoretical investigation of angular distribution of a single-photon superradiance from cold and dilute atomic clouds. In the present work we focus our attention on the dependence of superradiance on the size and shape of the cloud. We analyze the dynamics of the afterglow of atomic ensemble excited by pulse radiation. Two theoretical approaches are used. The first is the quantum microscopic approach based on a coupled-dipole model. The second approach is random walk approximation. We show that the results obtained in both approaches coincide with a good accuracy for incoherent fluorescence excited by short resonant pulses. We also show that the superradiance decay rate changes with size differently for radiation emitted into different directions.

We report the investigation of the peculiarities of excitation trapping caused by the cooperative effects in a disordered ensemble of point-like impurity centers (atoms) embedded in a transparent dielectric and located in a Fabry-Perot cavity. On the basis of the general quantum microscopic theory we have calculated cooperative spontaneous decay of an excited atom located in the center of a sample. It is shown that in the case when the distance between the mirrors of a cavity d is less or comparable with resonant wavelength of the atomic transition λ0, the character of cooperative effects in a cavity essentially differs from one without a cavity. For the opposite case d λ0 cooperative effects in a cavity manifest themselves almost like in the case of absence of a cavity.

Results of analysis are presented for a study of heat-resistant nickel alloy modification with a combined inoculator based on titanium carbonitride. The type of dependence of modified alloy grain size on temperature and time for holding a melt after introducing a combined inoculator is demonstrated. Data are provided for the degree of improvement for heat-resistant nickel alloy properties using combined inoculators.

We report the microscopic method for the calculation of the spontaneous decay of an excited atom located near a nanoparticle. The spontaneous decay dynamics, the atomic transition line shape as well as its shift have been analyzed. Different form, sizes and densities of the atomic cluster have been considered.

The processes of ion migration in glasses of the NaF–Na2O–B2O3system are studied electrochemically. The results obtained in electrolysis of glass samples in cells with different electrodes are analyzed. The applicability of the known techniques for investigating the nature of current carriers and determining their transport numbers in glasses is discussed. Analysis of the data obtained in electrolysis of the studied glasses in cells with a mercury cathode and anodes prepared from sodium amalgam, metallic silver, and vitreous sodium tetraborate has revealed that protons can participate in the electricity transport processes in addition to sodium and fluorine ions.

Bacteria that produce exopolysaccharides (EPS) and use methane as the only source of carbon were selected by studying a collection of methanotroph strains: Methylococcus capsulatusE 494, 874, and 3009; M. thermophilus111p, 112p, and 119p; Methylobacter ucrainicus159 and 161; M. luteus57v and 12b; Methylobactersp. 100; Methylomonas rubra15 sh and SK-32; Methylosinus trichosporiumOV3b, OV5b, and 4e; M. sporium5,12, A20d, and 90v; and Methylocystis parvusOVVP. Mesophilic methanotroph strains with the ribulose monophosphate way of C1-compound assimilation synthesized EPS more actively than bacteria operating the serine cycle. The dynamics of EPS synthesis by methanotrophs during chemostat cultivation was studied.

We pioneered the study of the electrode properties of glasses containing 80 and 85 wt % LiF and 20 and 15 wt % A1(PO3)3. LiF-80-based glass electrodes functioned as lithium-selective electrodes in 1-0.0001 M LiCl solutions. Contrary to aliminosilicate glasses, these glasses responded to the Li+ ion better than to the Na+ ion and were nonselective to the Hi+ ion. This made them promising for the development of sensors for Li+ ions in different solutions. Forward and reverse transitions of these glasses from the hydrogen to the lithium function and from the lithium to the sodium function are described by the equation of the simple Nikol’skii theory.

Glasses in the MeF2-Na2B4O7 (Me = Mg, Ca, Sr, and Ba) system have been synthesized. It is shown that the glass formation is observed at a MeF2 content of up to 40 mol %. The influence of the MeF2 content on the electrical conductivity and the fluorine concentration in the glass bulk is examined. From the analysis of the concentration dependence of the electrical conductivity with due regard for the fluorine content, it is concluded that the glass structure is predominantly built up of the polar groupings Na+[BO4/2]-, Na+[F-BO3/2], Me 1/2 2+ [BO4/2]−, Me 1/2 2+ [F−BO3/2], [MeF4/2], and [MeF6/3] and the BO3/2 nonpolar structural-chemical units. The electricity transport is governed by the migration of sodium ions formed upon dissociation of the Na+[BO4/2]-and Na+[F-BO3/2] groupings. An increase in the MeF2 content leads to a decrease in the total concentration of sodium ions, a decrease in the Na+[BO4/2]- concentration, and an increase in the Na+[F-BO3/2] concentration. Upon introduction of MeF2 up to ∼20 mol %, the fluorine losses during the synthesis are caused by the dehydration of glass melt. An addition of 20–25 mol % MeF2 brings about the saturation of the glass by the [F-BO3/2]-type structural units, so that the fluorine concentration reaches a saturation in the structures of calcium-, strontium-, and barium-containing glasses and increases in magnesium-containing glasses, owing to the formation of the [MgF+6/3] groupings.

The temperature–concentration dependence of the electrical conductivity of glasses in the NaPO3–NaF system has been investigated. The regularities revealed are interpreted from the standpoint of the structural microinhomogeneity of glasses, which is due to the formation of polar structural units of the Na+[O–POO2/2], Na2+[O–2POO1/2], Na+[F–POO2/2], and Na+F– types. It is shown that the concentration dependence of the electrical conductivity is governed by the ratio between the concentrations of these structural units.

The nature of current carriers is revealed and the concentration dependence of the true transport numbers of chlorine ions η is studied by the Tubandt method in glasses of the PbCl2-2PbO · SiO2 system. It is demonstrated that, in glasses containing up to ∼20 mol % PbCl2, the electricity transport occurs through protons and chlorine ions. At [PbCl2] ≥ 20 mol %, the electric current is carried primarily by the chlorine ions. The known crystalline compounds in the PbO-PbCl2 system are synthesized, and the temperature dependences of their electric conductivity are investigated for the first time. It is found that the introduction of PbCl2 into PbO is accompanied, first, by an increase in the electric conductivity (to a PbCl2 mole fraction of ∼0.5), and, then (when PbCl2 single crystals are formed), by its decrease. The temperature-concentration dependence of the electric conductivity for glasses in the PbCl2-2PbO · SiO2 system is interpreted in terms of structural-chemical microinhomogeneity of the glass structure due to the selective interaction of components during the glass synthesis.

Glasses in the Na2O–B2O3, NaF–Na2O–B2O3, and NaF–B2O3 systems have been synthesized. The nature of current carriers and their transport numbers in these glasses are determined by the Hittorf and Tubandt techniques. The concentration dependences of the electrical conductivity and the transport numbers are investigated. It is demonstrated that the electricity transport in glasses in the NaF–B2O3 system is provided by sodium and fluorine ions. The results obtained are interpreted in terms of the microinhomogeneous glass structure.

We investigate two-particle dispersion in fully developed turbulence within a Levy-walk stochastic model using a generalized Drude approach. Different from one-particle pictures we focus here on the time evolution of the relative distance between two particles. Based on the Kolmogorov-Obukhov energy spectrum and on the temporal correlations in the flow the Richardson t3-law follows as a Levy-type enhancement of rare events.

We report preliminary results on the transfer of the ammonia MBE technology of AlN/AlGaN/GaN/AlGaN heterostructures to silicon substrates. Optimization of the growth conditions allowed the number of macroscopic cracks in the epilayers to be reduced and ensured the growth of heterostructures with two-dimensional electron gas, which are suitable for the creation of field-effect transistors. The saturation current of prototype devices based on the heterostructures grown on silicon substrates are comparable with the analogous parameter of devices grown on sapphire and exhibits no decrease related to thermal scattering at high bias voltages.

in a change in the temperature distribution over the cross sections of the block, which determines internal restraint of individual parts of the block and restraint of the block in the foundation; in a change in the form of restraint of the mass as a whole in the rock foundation; in the formation of narrowed or expanded sections in the block, the stresses in which can substantially differ from adjacent ones; in the formation of stress raisers in the concrete for certain forms of the relief of the rock foundation due to jogs of the contact surface of the block and rock mass.

As a result of this work, the structure and composition of the technical means of an extrareactor system for measuring the nonuniformity of energy release in a BBER-440 core were determined. They make it possible to solve the problem posed with maximum utilization of standard systems without affecting the latter. Analysis of the measurement error in the average axial distribution of enerry release showed that the system for extrareactor measurement of the nonuniformity of energy release satisfies the technical requirements for it. It can be calibrated not only according to data from neutron-measurement channels but also according to neutron-physical calculations simulating the calibration tests. The first sample of an extrareactor measurement system was installed in the third power-generating unit of the “Kozlodui” nuclear power plant. The results of testing the system during the 13th run confirmed that the measurement method, the algorithm, and the software are successful and also that the instrumentation is reliable. A similar system has also been installed in the second power-generating unit of the “Kozlodui” nuclear power plant, and the system will be installed in the first and fourth power-generating units. The modified systems software made it possible to include the system in the general computer network and to output the measurement results on a monitor.

Sterically hindered 1,3-diketones react selectively with propargyl and allyl bromides under conditions of phase transfer catalysis to giveC-alkylated products, whereas reactions with butyl and benzyl chlorides yield mixtures ofC- andO-isomers. An increase in the size of the substituents present in the initial 1,3-diketone hampers introduction of the second propargyl group. The propargyl-substituted 1,3-diketones undergo cyclization under the alkylation conditions to give substituted furans.

The new β-diketones with a methoxy group of the type (R 1 R 2 )C(OCH 3 )COCH 2 COR 3 and their barium complexes have been synthesized. The barium β-diketonates obtained were identified and characterized by elemental, IR and Raman spectroscopic analyses. TG, DTG and DTA analyses carried out in vacuo and at atmospheric pressure have allowed the determination of the relative volatility and thermal stability of these barium complexes. The influence of the methoxy group, by type of substituent in the ligand, has been investigated by mass spectrometry. It has been found that the introduction of bulky end substituents into the ligand does not reduce the maximal oligomerization degree of barium β-diketonates in the gas phase.

In the weak field approximation, the nonsymmetric gravitational theory (NGT) has, in addition to the Newtonian gravitational potential, a Yukawa-like potential produced by the exchange of a spin $1^+$ boson between fermions. If the range $r_0=\mu^{-1}$ is $25$ kpc, then this additional potential due to the interaction with matter in the halos of galaxies can explain the flat rotation curves of galaxies and the Tully-Fisher law ($L\sim v^4$) without the dark matter hypothesis. Possible fits to clusters of galaxies and gravitational lensing observations are discussed. The results are based on a linear approximation to a new perturbatively consistent version of the NGT field equations, which does not violate the weak equivalence principle., Comment: 16 pages, REVTeX 3.0; correction of a misprinting

Modulation of the polarization state of a probe beam is used for the contactless detection of the alternating voltage induced across a Bi 12 TiO 20 sample by a spatially oscillating interference pattern. The measured voltage is up to 78% of the theoretical limit. The advantages of this technique as compared with conventional short-circuit current measurements are discussed, and a new all-optical technique for Hall mobility measurements is proposed.