Thermal pressure coefficients of ethanenitrile,propanenitrile, and butanenitrile in the region 295–395 K

The thermal pressure coefficient (p/T) _v has been measured for ethanenitrile from 299 to 364 K, for propanenitrile from 295 to 377 K, and for butanenitrile from 297 to 398 K. The results are discussed in terms of the diminishing role of polarity in the alkanenitrile series and of a corresponding-states approach using gas-liquid critical properties as reduction factors. Although (p/T) _v varies unevenly with chain length, the reduced quantity shows a more regular behavior similar to that of the related quantity the cohesive energy density.     

Theory of RF SQUIDs Operating in the Presence of Large Thermal Fluctuations

A comprehensive analytical theory is presented for non-hysteretic RF SQUIDs operating in the adiabatic mode in the presence of large thermal fluctuations. When 1 ( = 2LI_c/₀ is the hysteresis parameter, L is the SQUID inductance, I_c is the critical current of the Josephson junction, and ₀ is the flux quantum) the theory is applicable also for RF SQUIDs operating in the non-adiabatic mode. In contrast to previous theories in which the noise is treated perturbatively and which therefore are applicable only if the product 1 ( = 2k_BT/ ₀ I_c is the noise parameter, k_B is the Boltzmann constant, and T is the absolute temperature)—the case of small thermal fluctuations—the present theory is valid for around unity or higher. In the limit 0 the theory reproduces the results of small thermal fluctuations theories. It has been found that in the presence of large thermal fluctuations the screening current in the SQUID inductance is suppressed by a factor that increases with increasing . Taking into account this new basic fact, all SQUID characteristics (output signal, transfer function, noise spectral density and energy sensitivity) have been recalculated and a good agreement with experimental data has been obtained. It has been also found that RF SQUIDs can be operated with substantially higher values of the inductance and of the noise parameter than DC SQUIDs. These two aspects, which are of particular importance at liquid nitrogen temperature, make high T_c RF SQUIDs very attractive.     

Number of references in biochemistry and other fields; A case study of the Journal of Biological Chemistry throughout 1910–1985

Large samples of papers published in theJournal of Biological Chemistry in all decades and in some mid-decades werechecked in order to study the referencing pattern, throughout the period 1910–1985, in an internationally leading journal, with especially high citation impact. All measures show that there has been a significant growth in the number of references per paper, during most of the period, but mainly from the 1950's on, refuting Meadows' upper limit. A detailed comparison to a wide range of fields shows theJBC rates to be among the highest. Eight factors affecting the number of references are discussed, and some projections for the future are made.     

Steady-state creep in a 25 wt % Cr-20 wt % Ni austenitic stainless steel

Steady-state creep behaviour of a 25 wt % Cr-20 wt % Ni stainless steel without precipitates was studied in the stress range 9.8 to 39.2 MPa at temperatures between 1133 and 1193 K. The results of stress-drop tests indicate that, in the steady-state creep region, diffusion-controlled recovery creep is dominant. Such recovery creep can be accounted for in terms of the composition of the internal stress, _i=_s+_c, except in the case of fine-grained specimens where d<80 m, whered is the mean grain diameter, _s is possible to reduce easily and is comparable to the driving stress for creep, and _c is the persistent stress field due to metastable substructure. In the fine-grained specimens, it is suggested that the steady-state creep is dominantly controlled by grain boundaries.     

Formulas for evaluating the stabilization time of sluggish measuring instruments

Conclusions In this article formulas are suggested for calculating the stabilization time in ranges of 0<1 and 1.04<. These formulas are universal, they have a higher precision than has been hitherto obtained and they reflect the actual nature of the relationship between t_s and .Translated from Izmeritel'naya Tekhnika, No. 11, pp. 58–60, November, 1966.     

Paramagnetic resonance in a “dirty” spin-glass

For a spin-glass with nonmagnetic defects (n _m ^1/3l 1, where n _m is the magnetic impurity concentration and l is the mean free path) an absorption function () is derived. Three ranges of temperature and external magnetic field are considered. In the vicinity of the transition the value of () d is estimated as a function of temperature and field.     

Effect of the elastic factor on the hydrodynamic stability of a structurally viscous medium

The effect of relaxation phenomena on the hydrodynamic stability of the plane gradient flow of a structurally viscous medium is investigated using linear theory.Notation _ij stress tensor deviator - U_i components of the velocity vector - x_i coordinates - t time - P pressure - =₀L/^*V plasticity parameter - _o limiting shear stress - andc dimensionless wave number and the perturbation frequency - Re=VL/* Reynolds number - density - F_ij deformation rate tensor Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 5, pp. 868–871, November, 1978.     

Microstructure and crystallographic texture of rolled polycrystalline Fe3Al

An imperfectly B₂ ordered Fe₃Al aggregate was cast, thermomechanically hot rolled and finally annealed at 870 K. Subsequently, the specimen was rolled at 800–830 K to a strain of 80%. The microstructure and the crystallographic texture of the rolled polycrystalline sample was investigated within the range =20–80%. The microstructure consisted of flat, elongated grains. In numerous grains straight slip lines were detected. Even after =80% recrystallization was not observed. The rolling texture of Fe₃Al considerably deviates from that of non-ordered body centered cubic (b.c.c.) alloys and pure b.c.c. metals. The {111}uvw texture fibre (7-fibre) was very pronounced, while the {hkl}110 fibre (-fibre) was very weak. The {112}110 orientation which represents the strongest texture component in non-ordered b.c.c. alloys did not occur at all. The textures are discussed in terms of the {110}111, {112}111, {112}111 and {123}111 slip systems. The contribution of crystallographic slip of the various types of potential slip systems was simulated by means of the Taylor theory.     

Reconfirmation of the existence of δ2 in dental amalgams

The 90°C endotherm peak in the thermogram of a conventional dental amalgam is due to two overlapping peritectic transitions involving SnHg-2 and HgAgSn-1, respectively. The aim of the present study is to separate these two events and thus confirm that the 2 phase is indeed a part of an amalgam microstructure. The materials used in this study were: sample 1, 1+1 wt% Sn; sample 2, 1+2 wt% Sn; sample 3, 1+3 wt% Sn; and sample 4, a commercial conventional amalgam with 48 wt% Hg. In powder form, they were exposed to 1 wt% NaCl solution at 37 °C for up to 45 days. At 15 day intervals, samples were withdrawn from the solution, washed, dried and then characterized by the differential scanning calorimetry (DSC) technique. Corrosion of Sn from ternary 1 matrix and intergranular 2 in respective materials during their exposure to the NaCl solution led to the following: (a) a progressive increase in 11 transition temperature in samples 1 and 2; (b) a gradual decrease in 2 peak and its disappearance in sample 2; and (c) in samples 3 and 4, initial splitting of the 90°C peak into two distinct endotherms associated with 2 and 1, respectively. Continued corrosion of the last two materials produced further changes in 2 and 1 in a manner similar to that seen in samples 1 and 2. On the basis of these observations, we have concluded that the 90°C endotherm is a valid indicator of the existence of the 2 phase in dental amalgams.     

Phase equilibria in the Ag4SSe-ZnTe system

The Ag₄SSe-ZnTe phase diagram has been determined on the basis of X-ray diffraction, differential thermal and metallographic analyses, as well as microhardness and density data. It has been divided into two subdiagrams of eutectic type by an intermediate A-phase with most probable composition of 2Ag₄SSe.ZnTe. The unit-cell parameters of the low-temperature -2Ag₄SSe·ZnTe modification have been determined (a=3.330 , b=3.010 , c=2.895 , =95.04°, =107.83°, =92.62°). It has been supposed that in the ZnTe-rich part a second intermediate B-phase with a composition of Ag₄SSe·2ZnTe is formed, which is stable in the range of 320÷500 °C.