Showing papers on "Atmospheric temperature range published in 1979"
TL;DR: Analysis of the detailed results indicates that metabolic coordination within the normal (Arrhenius) range is largely achieved by modulation of enzyme activity rather than amount and the restricted growth that occurs outside this range is accompanied by marked changes in the levels of most of these proteins.
Abstract: The adaptation of Escherichia coli B/r to temperature was studied by measuring the levels of 133 proteins (comprising 70% of the cell9s protein mass) during balanced growth in rich medium at seven temperatures from 13.5 to 46 degrees C. The growth rate of this strain in either rich or minimal medium varies as a simple function of temperature with an Arrhenius constant of approximately 13,500 cal (ca. 56,500 J) per mol from 23 to 37 degrees C, the so-called normal range; above and below this range the growth rate decreases sharply. Analysis of the detailed results indicates that (i) metabolic coordination within the normal (Arrhenius) range is largely achieved by modulation of enzyme activity rather than amount; (ii) the restricted growth that occurs outside this range is accompanied by marked changes in the levels of most of these proteins; (iii) a few proteins are thermometer-like in varying simply with temperature over the whole temperature range irrespective of the influence of temperature on cell growth; and (iv) the temperature response of half of the proteins can be predicted from current information on their metabolic role or from their variation in level in different media at 37 degrees C.
361 citations
TL;DR: In this paper, a comparative review of hardness data and compressive creep measurements obtained under large confining pressures confirms the hypothesis of Rice [1971] that single-crystal hardness measurements, corrected for elastic effects, can be correlated to the fully ductile yielding of a polycrystal by dislocation mechanisms, including dislocation climb and glide.
Abstract: The variation of hardness with temperature was measured for olivine on a number of crystal faces by the Vickers diamond pyramid technique (up to 800°C) and by a mutual indentation technique (for temperatures up to 1500°C). A comparative review of hardness data and compressive creep measurements obtained under large confining pressures confirms the hypothesis of Rice [1971] that single-crystal hardness measurements, corrected for elastic effects, can be correlated to the fully ductile yielding of a polycrystal by intragranular dislocation mechanisms, including dislocation climb and glide. The computed differential yield stresses, σ (in gigapascals), which empirically correspond to a strain rate of 10−5 s−1, were well represented by an equation of the form σ = 9.1(±0.3) - 0.23(±0.01)T2, where T is the absolute temperature (in degrees Kelvin), and the quoted variances are for 1 standard deviation. The olivine data therefore predict a high-stress polycrystalline flow law that may be expressed as = 1.3 × 1012exp - [(60×103)/T][1 - (σ/9.1)]2 where is the strain rate in s−1. A similar functional dependence of strain rate on stress is indicated for Al2O3 for temperatures below 900°C but is contraindicated for MgO and NaCl. Using a semiempirical method of dislocation rosette analysis, the critical resolved shear stress on the {110} [001] slip system was estimated (to 20%) over the temperature range 20°C to 780°C as 1.2 GPa and 0.3 GPa, respectively. These data are useful in providing an upper bound to the yield stress in a region of stress and temperature space not easily accessible by other experimental methods.
297 citations
TL;DR: In this paper, the flow stress of Ni3(Al, Nb) single crystals has been measured as a function of orientation in the temperature range 77 to 910 K. The flow stress behavior is similar to that observed in other Ni3Al-based alloys, but the absolute value of the stress was found to be much higher.
Abstract: The flow stress of Ni3(Al, Nb) single crystals has been measured as a function of orientation in the temperature range 77 to 910 K. While the increasing flow stress behavior is similar to that observed in other Ni3Al-based alloys, the absolute value of the stress was found to be much higher. Also, the effect of orientation changes was to produce much greater changes in the temperature at which the peak flow stress occurs than has been previously observed. The operative slip systems were analyzed by two surface slip trace analysis. Primary octahedral slip was found to be predominant at temperatures below the peak stress temperature, while primary cube slip is prevalent above the peak temperature. The anomalous increase in the flow stress of Ni3(Al, Nb) with increasing temperature is generally consistent with the thermally activated cross-slip of a/2 dislocations from {111} planes onto {100} planes. The cross-slip is shown to be aided not only be the resolved shear stress on the {100} cross-slip plane but also by the stress tending to constrict the a/ Shockley partial dislocations on the primary glide plane.
278 citations
TL;DR: In this article, the transition from a semi-conducting to a metallic phase occurs over a temperature range of 0.1'K with a corresponding volume change of 1.044%.
Abstract: Accurate lattice parameters and thermal expansion coefficients of the low- and high-temperature phases of VO2 have been determined from measurements on single crystals with the Bond method [Acta Cryst. (1960), 13, 814–818]. The transition from a semi-conducting to a metallic phase occurs over a temperature range of 0.1 K with a corresponding volume change of 0.044%.
155 citations
TL;DR: In this article, the single crystal elastic constants of aluminum have been measured using a piezoelectric composite oscillator from room temperature to just 20 K below the melting point, and the elastic moduli differ markedly from previous high temperature results, but match in well with previous cryogenic results.
149 citations
TL;DR: In this article, temperature-stable surface-acoustic-wave (SAW) devices have been fabricated with an rf−sputtered SiO3 film overlay on YZ LiTaO2.
Abstract: Temperature‐stable surface‐acoustic‐wave (SAW) devices have been fabricated with an rf‐sputtered SiO3. film overlay on YZ LiTaO2. The material properties of this composite structure relevant to surface‐acoustic‐wave propagation have been thoroughly studied. For an SiO2 film thickness of approximately one‐half of an acoustic wavelength, a piezoelectric coupling coefficient of 0.014 is present and the temperature stability of phase delay is similar in magnitude to that of bulk acoustic waves in AT‐cut quartz. A variation in delay of less than one part in 105 is observed over the temperature range −40 to 80 °C. The film‐overlay structure is dispersive and the nature of this dispersion has been fully characterized. The dependence of the phase and group delay on temperature and frequency has been measured. For most characteristics, theoretical as well as experimental values have been determined. In addition to YZ LiTaO3, five other cuts of LiTaO3 have been analyzed theoretically. To demonstrate potential appli...
123 citations
TL;DR: In this paper, a significant decrease in resistivity has been observed in glow-discharge-produced silicon (GDSi) containing 1019−1021 cm−3 phosphorous atoms.
Abstract: Significant decrease in resistivity has been observed in glow-discharge-produced silicon (GDSi) containing 1019−1021 cm−3 phosphorous atoms. At the highest doping level a resistivity of 0.01 ω cm at room temperature was obtained. The temperature dependence of the resistivity follows the form, ϱ = ϱ0exp(T0/T)14, over a temperature range from 80–400 K. Optical absorption, which increased with wavelength and was roughly proportional to the conductivity, was observed in the longer wavelength side of the intrinsic absorption edge and it was ascribed to mobile charge carriers. Hall effect measurements have shown that μH of phosphorus doped GDSi is about 1 cm2 V−1s−1 and has a normal (negative) sign.
112 citations
TL;DR: In this article, the Auger de-excitation mechanism was shown to be proportional to the number of free electrons in the Schottky barrier in the presence of trapped and free electrons.
102 citations
TL;DR: In this article, the authors investigated the 7Li nuclear magnetic relaxation time T1 and of the broad line spectra over a wide temperature range for binary and ternary alkali silicate, alkali borate, and alkali phosphate glasses.
93 citations
TL;DR: Amorphous poly(ethylene terephthalate) has been isothermally annealed in a wide range of temperatures from Tg to Tm and the effects of temperature and time of thermal treatment on density, melting curve and WAXS have been systematically explored as discussed by the authors.
90 citations
TL;DR: Inelastic neutron scattering was used to study structural phase transitions in polyphenyls as mentioned in this paper, which result from the stabilization of the nonplanar molecular configuration with respect to a torsional angle between the planes of phenyl rings.
TL;DR: In this article, the reactivity of solid silicon with a dydrogen has been studied in a temperature range between about 10°C and ≈540°C at discharge currents up to ≈420 mA and a pressure of ≈0.13 mbar (0.1 torr).
TL;DR: In this paper, the authors used the permeability time-lag method to determine the diffusivity of hydrogen in palladium in the temperature range 496-946°C.
TL;DR: In this article, the current peaks due to transient SCLC were observed both in high-density polyethylene (HD-PE) and in oxidised HD-PE in the temperature range 50-90 degrees C.
Abstract: Current peaks due to transient SCLC were observed both in high-density polyethylene (HD-PE) and in oxidised HD-PE in the temperature range 50-90 degrees C. From the time at which the current peak occurs, carrier mobilities ranging from 10-11 to 10-9 cm2 V-1 s-1 were obtained. The mobility values obtained agree well with those evaluated from surface-charge decay measurements. They strongly depend upon applied field and temperature. The charge carriers have a much lower mobility in oxidised HD-PE than in non-oxidised HD-PE. This is attributed to the introduction of deep traps by the oxidation.
TL;DR: The hexagonal cell dimensions a and c of 2H-MoS2 and WSe2 have been measured over the temperature range 10 to 320 K as discussed by the authors, and the linear coefficients of thermal expansion in both directions were approximately equal.
Abstract: The hexagonal cell dimensions a and c of 2H-MoS2 and 2H-WSe2 have been measured over the temperature range 10 to 320 K. In both compounds a increased linearly and c non-linearly with temperature, the linear coefficient of thermal expansion in the c direction being greater than that in the a direction for 2H-MoS2. In 2H-WSe2 the linear coefficients of thermal expansion in the a and c directions were approximately equal.
TL;DR: In this paper, the coefficient of thermal expansion has been determined in the temperature range 25-400°C for InP, the ternary alloy Ga0.47In0.53As, and the quaternary alloy GA0.26In 0.74As0.40P0.60
Abstract: The coefficient of thermal expansion has been determined in the temperature range 25–400 °C for InP, the ternary alloy Ga0.47In0.53As, and the quaternary alloy Ga0.26In0.74As0.40P0.60 grown on (100) InP by liquid‐phase epitaxy. This parameter is (4.56±0.10) ×10−6/°C for InP, (5.42±0.10) ×10−6/°C for Ga0.26In0.74As0.60P0.40, and (5.66±0.10) ×10−6/°C for Ga0.47In0.53As.
TL;DR: In this paper, tracer diffusion and ionic conductivity were measured on the same single crystals of sodium beta-alumina of composition 1.23 Na20.11 Al2O3.
TL;DR: In this paper, a relaxed lattice was used to fit satisfactorily the experimental pair correlation function for liquid mercury in the presence of both CuKα and MoKα radiation.
Abstract: The structure of liquid mercury has been studied with both CuKα and MoKα radiation using a theta–theta diffractometer with monochromator in the diffracted beam. Special attention has been paid to the temperature dependence of the liquid structure and the use of small droplets of about 5 μm diameter actually allowed measurements on supercooled liquid down to 60 K below the normal melting point. No significant variation in the first coordination number is observed over the temperature range studied, the change in the shape and the height of the first peak of the structure factor being probably due to some long range correlation increase when the temperature is lowered. A structure model based on a relaxed lattice is found to fit satisfactorily the experimental pair correlation function for liquid mercury.
TL;DR: In this paper, the authors show that when a Pd layer is interposed between Si and V, the bilayer system starts to react at <300°C with the formation of Pd2Si.
Abstract: Solid phase reactions in the temperature range between 250 and 600 °C between Si and V‐Pd bilayers as well as alloy layers have been studied by MeV 4He+ backscattering and x‐ray diffraction techniques. When a Pd layer is interposed between Si and V, the bilayer system starts to react at <300 °C with the formation of Pd2Si. Annealing at higher temperatures (∼600 °C) leads to a uniform layer of VSi2 formed on top of the Pd2Si. Reversing the bilayer sequence (Si/V/Pd) raises the reaction temperature of the system to ∼500 °C with V mixing into the Pd layer. Annealing at higher temperature leads to the formation and accumulation of Pd2Si at the interface and a mixed (nonuniform) structure of Pd2Si and VSi2 in the outer surface region. For a Pd‐rich alloy (Pd80V20), a reaction started at about 300 °C and produced Pd2Si by depleting Pd from the alloy. This resulted in a mixed structure of Pd2Si and VSi2 in the outer region, similar to the final stage of the Si/V/Pd system. For a V‐rich alloy (Pd90V10), the forma...
TL;DR: In this article, a thorough investigation has been done about the behavior of natural diamond as a radiation detector material for a wide temperature range, and the average energy required to create an electron-hole pair and energy resolution have been measured in the 100 K - 400 K interval.
Abstract: A thorough investigation has been done about the behavior of natural diamond as a radiation detector material for a wide temperature range. Drift velocities and mean free drift time have been determined at temperatures ranging between 85 K and 700 K and with electric fields up to 60 KV/cm. Average energy required to create an electron-hole pair and energy resolution have been measured in the 100 K - 400 K interval. The spectroscopic features of diamond detectors have also been analyzed on a broad temperature interval. It was found that as T approaches 500 K polarization phenomena begin, thus establishing the upper temperature limit for the detector operation.
TL;DR: In this paper, the authors developed PbTiO3 ceramics with very small temperature coefficients of less than 1 ppm/°C over a wide temperature range (−10−+60°C) with a large electromechanical coupling factor and low dielectric constant.
Abstract: Lead titanate PbTiO3 ceramics with a zero temperature coefficient of surface wave delay time are developed by addition of Nd2O3, In2O3, and MnO2. These ceramics have very small temperature coefficients of less than 1 ppm/ °C over a wide temperature range (−10–+60 °C). They have a large electromechanical coupling factor and low dielectric constant. The propagation loss is 4 dB/cm at 57 MHz. These modified PbTiO3 ceramics have high potential for use in surface wave applications, e.g., filters.
TL;DR: In this paper, the authors measured the thermal variation of attenuation for multi-component and high-silica glass fibers at 0.63 μm wavelength in a temperature range from 20°C to 600°C.
Abstract: Thermal variation of attenuation for multi-component and high-silica glass fibers has been measured at 0.63 μm wavelength in a temperature range from 20°C to 600°C. The multicomponent glass fibers have shown no increase in loss below 400°C, whereas the high-silica glass fibers have shown a drastic, exponential increase in loss with increasing temperature. The observed change of attenuation has been explained on the basis of the shift of the ultra-violet absorption band calculated from temperature change of refractive index. The increase in optical loss, calculated from the obtained data of refractive index and dispersion parameters at each temperature, shows good agreement with the observed increase in loss.
TL;DR: In this article, the Schottky barrier height was measured in the temperature range 250-650°C between (100) Si and Pd•W binary alloy films of composition Pd80W20/Pd30W70 by a combination of ion backscattering, x-ray diffraction, and current-voltage measurement of the barrier height.
Abstract: Contact reactions in the temperature range 250–650 °C between (100) Si and Pd‐W binary alloy films of composition Pd80W20 and Pd30W70 have been studied by a combination of ion backscattering, x‐ray diffraction, and current‐voltage measurement of Schottky barrier height. For the Pd‐rich alloy, the reaction around 400 °C produced the silicide Pd2Si by depleting Pd from the alloy and resulted in the formation of a two‐layer structure, W/Pd2Si/Si. We have found that the W layer has served effectively as a diffusion barrier for the subsequently deposited Al, indicating that a rectifying contact and its diffusion barrier can be fabricated simultaneously. At higher reaction temperatures, the W layer transforms to WSi2 with some mixture of Pd2Si. The alloying of Pd with W has been found to increase the formation temperature of Pd2Si but decrease that of WSi2. In the Pd80W20 reaction, Pd2Si forms around 400 °C and WSi2 around 500 °C. In the Pd30W70 reaction, Pd2Si forms around 500 °C and WSi2 around 650 °C.
TL;DR: In this paper, the principal complex dielectric constants have been studied at audio frequencies over the temperature range 5.5-380K for α-quartz, sapphire, magnesium fluoride, and calcite.
TL;DR: In this paper, Knoop hardness measurements have been made on the (0001), {1010} and {1120} planes of 6H-SiC single crystals in the temperature range from room temperature to 1600 °C.
Abstract: Knoop hardness measurements have been made on the (0001), {1010} and {1120} planes of 6H-SiC single crystals in the temperature range from room temperature to 1600 °C. The hardness varies with the orientation of the long axis of the indenter on each plane. For all planes the hardness anisotropy is dependent on the temperature and the converse anisotropy was observed at temperatures below and above about 300–400 °C. It is concluded from the hardness anisotropy that the active slip system of 6H-SiC is {1010}〈1120〉 near room temperature and (0001)〈1120〉 at high temperatures. At about 300–400 °C both the basal and prismatic slip systems are operative. The 〈1120〉 slip lines are observed around Knoop and Vickers indentations only on the prismatic planes at approximately 800 °C, above which they become pronounced with increasing temperature. This suggests that the plasticity of 6H-SiC will increase substantially above 800 °C.
TL;DR: The magnetic moments of tris(NN-disubstituted dithiocarbamato)iron(III) complexes have been measured in solution over a wide temperature range, using an nmr method as discussed by the authors.
Abstract: The magnetic moments of four tris(NN-disubstituted dithiocarbamato)iron(III) complexes have been measured in solution over a wide temperature range, using an nmr method The assumption of a simple Boltzmann distribution between high- and low-spin forms (6A1 and 2T2) gives a good fit to the observed susceptibility data ΔS is approximately constant at ca 20 J K–1 mol–1 Solvent effects are small and there is no evidence that hydrogen bonding to chloroform is important in solution The paramagnetic shifts in the 1H nmr spectrum of one complex as a function of temperature have been analysed and give thermodynamic parameters in good agreement with those obtained from the susceptibility measurements
TL;DR: In this paper, the magnetic and magneto-optic properties of rare earth transition metal alloys have been investigated in the temperature range 4.2 K?T?TC and the compensation temperature is found to decrease strongly with increasing y (Tcomp=0 for x = 0.74, y=0.1) while the Curie temperature and the temperature for crystallization are much less affected.
Abstract: Amorphous rare‐earth‐transition metal alloys of composition (Gd1−xFex)1−yBiy with 0?y?0.17 have been prepared by high vaccum electron gun evaporation onto rotating glass substrates. The magnetic and magneto‐optic properties have been investigated in the temperature range 4.2 K?T?TC. From the temperature dependence of the saturation magnetization the compensation temperature is found to decrease strongly with increasing y (Tcomp=0 for x=0.74, y=0.1) while the Curie temperature and the temperature for crystallization are much less affected. The magneto‐optic Faraday and Kerr rotation display a considerable increase with increasing Bi‐content. The temperature behavior can be interpreted in terms of the mean field analysis indicating a pronounced influence of the bismuth on the iron moment and the exchange constants.
TL;DR: In this paper, a backscattering technique was used to study the reaction of titanium thin films with silicon and with SiO 2 in the temperature range 500-600°C.
TL;DR: In this paper, the glass transition temperature T g, the crystallization temperature T c and the heat of crystallization ΔH c were found to increase monotonically with increasing copper content over the composition range studied.