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  • 1
    Electronic Resource
    Electronic Resource
    The intensity distribution in the focus of curved-crystal monochromators and an estimate of its influence on precision measurements of lattice parameters (1960)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 13 (1960), S. 832-835 
    Details
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0365110X60002028
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  • 2
    Electronic Resource
    Electronic Resource
    Monoterpene hydrocarbon contents of the resin from seeds of silver fir (Abies alba Mill.) (1987)
    Springer
    Trees 1 (1987), S. 94-101 
    Details
    ISSN: 1432-2285
    Keywords: Monoterpenes ; Abies alba Mill ; Resin ; Seeds ; Gas chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Using gas-chromatographic methods, the variability of the contents of monoterpene hydrocarbons (α-pinene, β-pinene, Δ3carene and limonene) in the resin of silver fir seeds (Abies alba Mill.) was studied. Resin cavities were characterized according to their position on the seed surface. It was estabilished that the terpene content of the resin of cavities localized on the abaxialadaxial surfaces of the seed differs significantly, creating a gradient of resin composition around the circumference of the seed. The differences between various resin cavities of single seeds were greater than the differences between different seeds of a single cone and between seeds of various cones on a single tree. An accurate definition of the resin cavity location on the seeds appears to be a fundamental condition for the collection of a sample representing the resin composition of individual trees. Resin biosynthesis in the course of organogenesis and the control of terpene contents in the resin of various locations on the seed and the cone are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203577
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  • 3
    Electronic Resource
    Electronic Resource
    A flow visualization technique for low-speed wind-tunnel studies (1987)
    Springer
    Experiments in fluids 5 (1987), S. 212-214 
    Details
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The paper describes a flow visualization technique (direct injection method) used in low-speed wind-tunnel studies. Mixture of titanium tetrachloride and carbon tetrachloride is used to produce closely spaced parallel streaklines of white smoke of long duration. The technique is described in detail and representative photographs of various flow patterns are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298465
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  • 4
    Electronic Resource
    Electronic Resource
    Canopy transpiration and water fluxes in the xylem of the trunk of Larix and Picea trees — a comparison of xylem flow, porometer and cuvette measurements (1985)
    Springer
    Oecologia 66 (1985), S. 475-483 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Leaf gas exchange, transpiration, water potential and xylem water flow measurements were used in order to investigate the daily water balance of intact, naturally growing, adult Larix and Picea trees without major injury. The total daily water use of the tree was very similar when measured as xylem water flow at breast height or at the trunk top below the shade branches, or as canopy transpiration by a porometer or gas exchange chamber at different crown positions. The average canopy transpiration is about 12% lower than the transpiration of a single twig in the sun crown of Larix and Picea. Despite the similarity in daily total water flows there are larger differences in the actual daily course. Transpiration started 2 to 3 h earlier than the xylem water flow and decreased at noon before the maximum xylem water flow was reached, and stopped in the evening 2 to 3 h earlier than the water flow though the stem. The daily course of the xylem water flow was very similar at the trunk base and top below the lowest branches with shade needles. The difference in water efflux from the crown via transpiration and the water influx from the trunk is caused by the use of stored water. The specific capacitance of the crown wood was estimated to be 4.7 x 10-8 and 6.3 x 10-8 kg kg-1 Pa-1 and the total amount of available water storage was 17.8 and 8.7 kg, which is 24% and 14% of the total daily transpiration in Larix and Picea respectively. Very little water was used from the main tree trunk. With increasing transpiration and use of stored water from wood in the crown, the water potential in the foliage decreases. Plant water status recovers with the decrease of transpiration and the refilling of the water storage sites. The liquid flow conductance in the trunk was 0.45 x 10-9 and 0.36 x 10-9 mol m-2s-1 Pa-1 in Larix and Picea respectively. The role of stomata and their control by environmental and internal plant factors is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379337
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  • 5
    Electronic Resource
    Electronic Resource
    The effect of a partially inserted absorbing control rod on the neutron flux density distribution (1961)
    Springer
    Atomic energy 9 (1961), S. 1010-1016 
    Details
    ISSN: 1573-8205
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Physics
    Notes: Abstract This paper presents a method of calculating the effectiveness of a partially inserted absorbing, cylindrical control rod in a reactor without a reflector. The method makes it possible to give a comparatively simple estimate of the distortion of the neutron flux density near the control rod. The calculations are made using the one group equation Δϑ + B2ϑ = 0, with special boundary conditions on the surface of the rod. As an example of the use of the method, the values of B2 and the corresponding flux distributions ϑ have been calculated for several positions of the rod in the reactor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01487461
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  • 6
    Electronic Resource
    Electronic Resource
    Choice of parameters of an X-ray monochromating unit (1962)
    Springer
    Czechoslovak journal of physics 12 (1962), S. 602-613 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Abstract В последнее время в ра ботах был упомянут ме тод расчета волнового распредел ения в обычных экспериментальных устройствах. В этой статье рассмотрен пример пр именения метода к монохроматизирующ ему элементу Johansson. Показа но, что можно найти условие, при котором можно достигнуть требуемой ширины монохроматизиров анного волнового интервала и максимальную интенсивность. Анализ показывает, что применять очень остр ые фокусы не выгодно, и что кристаллы не должны быть ни очень совершенными, ни слиш ком несовершенными. Оптимальные условия необходимо определи ть специально в каждом конкретном случае.
    Notes: Abstract In recent papers a way of computing the monochromated wavelength distribution in some current experimental arrangements was presented. In this paper an application is shown for the Johansson monochromating unit. The conditions are indicated for attaining the desired breadth of the monochromated interval and for its maximum intensity. The analysis implies that it is not advantageous to use very narrow foci and that the crystals should be neither very perfect nor very imperfect. The optimum conditions must be found in each case separately.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01690113
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  • 7
    Electronic Resource
    Electronic Resource
    A contribution to the theory of X-ray monochromators (1962)
    Springer
    Czechoslovak journal of physics 12 (1962), S. 588-601 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Abstract Введено понятие характеристической функции, полностью описывающей монорхоматизирующе е действие рентгенов ских монохроматоров. Даны формы этой функции для част о применяемых монохроматизирующи х элементов. Рассмотр ен пример расчета для элемента показывающий услов ия в одном частном слу чае. Кривые, дающие смещение цент ра тяжести волнового ра спределения монохро матического излучения для криста ллов различной степени совершеннос ти, позволяют сделать заключения о влиянии юстировки к ристалла на точные измерения пос тоянных решетки. Пред ложенная модель была проверен а экспериментально. Расчеты для данного экспериментального устройства позволяют п ростое опре деление эффективной ширины кривой отражения, если измерить расстояние между двумя соответственн о выбранными линиями поликристаллическо г о образца. Кроме того, экспериме нтально было установлено, что малый упругий изгиб не изменяет существенно кривую отражения несовершенных крист аллов с хорошими упру гими свойствами, если в кри сталле нет макроскоп ических деформаций.
    Notes: Abstract The characteristic function is introduced, describing completely the monochromating effect of monochromating units. Expressions for this function are presented for monochromating units frequently used. An example of computation for Johansson's unit shows the conditions in a special case. The curves indicating the shift of the wavelength centroid of monochromated radiation for crystals of different perfection allow conclusions to be drawn about the influence of the alignment of the crystal on precision measurements of lattice constants. The experiments verify the suggested model. The computations for a given experimental arrangement permit a simple determination of the effective breadth of the reflection curve, if a distance of two suitably chosen diffraction lines of a polycrystalline specimen is measured. Finally, it was found experimentally that a small elastic bending does not essentially alter the reflection curve of highly elastic and imperfect crystals unless macroscopic distortions are present.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01690112
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  • 8
    Electronic Resource
    Electronic Resource
    Graphical solution of chromatic and geometric focusing of X-ray diffraction lines (1964)
    Springer
    Czechoslovak journal of physics 14 (1964), S. 646-651 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A nomograph and a transparent chart, serving for the rapid determination of the simultaneous chromatic and geometric focusing of X-ray diffraction lines, are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01688609
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  • 9
    Electronic Resource
    Electronic Resource
    Chromatic focusing of X-ray diffraction lines and achromatic camera (1964)
    Springer
    Czechoslovak journal of physics 14 (1964), S. 629-645 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The conditions for simultaneous suppression of the wave-length component (broadening) and instrumental component (broadening) of the X-ray diffraction lines are analyzed. The fulfilment of the chromatic focusing conditions theoretically restrains the wave-length component as if we used an infinitely narrow wave-length interval in the incident beam. This is advantageous particularly in measuring the line profiles, as the precision of profile analysis can thus be appreciably increased. This paper presents general considerations and computations for a given experimental set-up. A camera suitable for this kind of measurement is described and the profile of a line withϑ=74·3° in an achromatic arrangement and in an ordinary back-reflection camera is compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01688608
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  • 10
    Electronic Resource
    Electronic Resource
    Wavelength distribution of X-rays in the focus of a monochromator and an estimate of the influence of this distribution on precision measurements of lattice constants (1960)
    Springer
    Czechoslovak journal of physics 10 (1960), S. 215-224 
    Details
    ISSN: 1572-9486
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Abstract Рассчитано распреде ление энергии в φокус е монохроматора с φок усировкой Иогансона при предположении, чт о известно распредел ение яркости в φокусе лампыG(α,) кривая отражения кри сталлаR(α) и распредел ение энергииJ(λ-λ0) пад ающего излучения. Оказывается, что напр имер, местоположение центра тяжести дубле таКα может существенно изменят ься в зависимости от м естоположения крист алла на φокусной окружности, что сильн о может повлиять на то чные измерения посто янных решетки.
    Notes: Abstract Wavelength distribution in the focus of a Johansson type monochromator is computed assuming the tube focus emissivityG(α), reflection curveR(α) and wavelength distribution of the incident radiationJ(λ-λ0) are known. It is shown e.g. that the centre of gravity may be shifted in accordance with the position of the crystal on the focal circle which may considerably influence precision measurements of lattice parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01557264
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