Thermal correction of quasistatic optical distortions in a VUV lithograph

For a projection objective of a lithographic setup designed for the wavelength range λ = 13 nm, optical distortions of its mirror components should not exceed a value of about 1 nm. The fabrication of mirrors of such an optical quality is very expensive. We have studied the possibility of using the thermal deformation of an optical element to improve the quality of its surface shape. It is shown, in particular, that, with this method, quasistatic large-scale (no smaller than 20% of the element diameter) optical distortions with an amplitude of about 15 nm can be compensated with an error up to 0.5 nm, that is, λ/20–λ/30.     

Synthesis of aryl-containing terpenoids based on 1,4-dihydronaphthalene

Successive transformations including oxidation of 1,4-dihydronaphthalene into 1,2,3,4-tetrahydronaphthalen-2-one, Reformatskii reaction of the latter with methyl bromoacetate, ozonolysis of the Reformatsky reaction product, and Emmons olefination of the aldehyde group in methyl 3-oxo-5-(2-formylphenyl)pentanate thus formed gave analogs of highly active dienoate juvenoids having an aromatic ring in their molecules.     

Numerical simulation of crystal growth processes by means of horizontal unidirectional crystallization from melts with different Prandtl numbers

The dependence of the form of a water solidification front on time in a rectangular chamber bounded by two vertical walls heated to different temperatures is studied numerically. One wall is suddenly cooled to a temperature below the freezing point. Calculations are performed allowing for the heat of crystallization and inversion in the dependence of water density on temperature.     

Numerical modeling of the process of heating a petroleum stratum by means of high-frequency electromagnetic radiation

Conclusions We have completed a numerical study on a two-dimensional model in which consideration has been given to the nonlinear heat-capacity function c(T) of the heating process for a petroleum stratum. It has been demonstrated that the efficiency of the heating depends significantly on correct selection of the parameters, and we have particular reference here to the absorption factor a defined by the radiation frequency. We have determined the optimum values of , as well as the optimum heating times. We have carried out calculations to confirm the possibility of utilizing high-frequency electromagnetic heating of petroleum strata in order to intensify the production yield of high-viscosity petroleum and to combat other well problems, and these can also be utilized for the development of practical recommendations.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 59–64, July–August, 1990.     

Three-dimensional structure of Erwinia carotovora L-asparaginase

Three-dimensional structure of Erwinia carotovora L-asparaginase, which has antitumor activity and is used for the treatment of acute lymphoblastic leukemia, was solved at 3 Å resolution and refined to R _cryst = 20% and R _free = 28%. Crystals of recombinant Erwinia carotovora L-asparaginase were grown by the hanging-drop vapor-diffusion method from protein solutions in a HEPES buffer (pH 6.5) and PEG MME 5000 solutions in a cacodylate buffer (pH 6.5) as the precipitant. Three-dimensional X-ray diffraction data were collected up to 3 Å resolution from one crystal at room temperature. The structure was solved by the molecular replacement method using the coordinates of Erwinia chrysanthemi L-asparaginase as the starting model. The coordinates refined with the use of the CNS program package were deposited in the Protein Data Bank (PDB code 1ZCF).     

Natural arylterpenes and their biological activity

Information on naturally occurring aromatic mono-, sesqui-, and diterpenes was systematized. The types of their biological activity and possible practical applications were described. Possible synthetic pathways to the most important terpenes were examined. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–13, January–February, 2006.     

Sources of 1/F noise in gallium arsenide IMPATT diodes

The quasistatic approximation is used to analyze 1/F noise in IMPATT diodes in the static and dynamic (self-oscillating) modes. Sources of 1/F noise are defined in accordance with the fluctuator model: allowance is made for fluctuations of the charge of traps and fluctuations of the electron drift velocity caused by their scattering by traps and metastable neutral centers. It is shown that the fluctuations of the voltage across the diode and the fluctuations of the oscillation frequency are mainly determined by the fluctuations of the trap charge, while the fluctuations of the oscillation amplitude are determined by scattering by neutral centers. A method is developed to determine the intensity of noise sources using the results of measurements of the fluctuations in the static and dynamic modes of IMPATT diodes and a method of checking the model as a whole is checked. Experimental results are presented and these show satisfactory agreement with the calculations. Zh. Tekh. Fiz. 67, 65–70 (August 1997)     

Electrochemical Properties of N-Substituted α-Diphenylphosphinoglycines

Russian Journal of Electrochemistry - The electrochemical properties of the N-substituted α-diphenylphosphinoglycines N-(2-methoxybenzyl) diphenylphosphinoglycine (1), N-(pyrazin-2-yl)...