The Royal Society
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Các bài báo tiêu biểu
The determination of the elastic field of an ellipsoidal inclusion, and related problemsIt is supposed that a region within an isotropic elastic solid undergoes a spontaneous change of form which, if the surrounding material were absent, would be some prescribed homogeneous deformation. Because of the presence of the surrounding material stresses will be present both inside and outside the region. The resulting elastic field may be found very simply with the help of a sequenc... ...
Tập 241 Số 1226 - Trang 376-396 - 1957
Quantal phase factors accompanying adiabatic changesA quantal system in an eigenstate, slowly transported round a circuit C by varying parameters R in its Hamiltonian Ĥ(R), will acquire a geometrical phase factor exp{iγ(C)} in addition to the familiar dynamical phase factor. An explicit general formula for γ(C) is derived in terms of the spectrum and eigenstates of Ĥ(R) over a surface spanning C. If C lies near a degeneracy of Ĥ, γ(C) takes... ...
Tập 392 Số 1802 - Trang 45-57 - 1984
Natural evaporation from open water, bare soil and grassTwo theoretical approaches to evaporation from saturated surfaces are outlined, the first being on an aerodynamic basis in which evaporation is regarded as due to turbulent transport of vapour by a process of eddy diffusion, and the second being on an energy basis in which evaporation is regarded as one of the ways of degrading incoming radiation. Neither approach is new, but a combination... ...
Tập 193 Số 1032 - Trang 120-145 - 1948
On kinematic waves II. A theory of traffic flow on long crowded roadsThis paper uses the method of kinematic waves, developed in part I, but may be read independently. A functional relationship between flow and concentration for traffic on crowded arterial roads has been postulated for some time, and has experimental backing (§2). From this a theory of the propagation of changes in traffic distribution along these roads may be deduced (§§2, 3). The theory i... ...
Tập 229 Số 1178 - Trang 317-345 - 1955
A theory of the yielding and plastic flow of anisotropic metalsA theory is suggested which describes, on a macroscopic scale, the yielding and plastic flow of an anisotropic metal. The type of anisotropy considered is that resulting from preferred orientation. A yield criterion is postulated on general grounds which is similar in form to the Huber-Mises criterion for isotropic metals, but which contains six parameters specifying the state of anisotrop... ...
Tập 193 Số 1033 - Trang 281-297 - 1948
Disintegration of water drops in an electric fieldThe disintegration of drops in strong electric fields is believed to play an important part in the formation of thunderstorms, at least in those parts of them where no ice crystals are present. Zeleny showed experimentally that disintegration begins as a hydrodynamical instability, but his ideas about the mechanics of the situation rest on the implicit assumption that instability occurs wh... ...
Tập 280 Số 1382 - Trang 383-397 - 1964
Stability of polyatomic molecules in degenerate electronic states - I—Orbital degeneracyIn the following we investigate the conditions under which a polyatomic molecule can have a stable equilibrium configuration when its electronic state has orbital degeneracy, i. e. degeneracy not arising from the spin. We shall show that stability and degeneracy are not possible simultaneously unless the molecule is a linear one, i. e. unless all the nuclei in the equilibrium configuration... ...
Tập 161 Số 905 - Trang 220-235 - 1937
The penetration of a fluid into a porous medium or Hele-Shaw cell containing a more viscous liquid
When a viscous fluid filling the voids in a porous medium is driven forwards by the pressure of another driving fluid, the interface between them is liable to be unstable if the driving fluid is the less viscous of the two. This condition occurs in oil fields. To describe the normal modes of small disturbances from a plane interface and their rate of growth, it is necessary to... ...
Tập 245 Số 1242 - Trang 312-329 - 1958
A new sensitive chemical actinometer - II. Potassium ferrioxalate as a standard chemical actinometer
The earlier experiments with potassium ferrioxalate have been extended and a detailed study has been made of the photolysis of the acidified solutions previously recommended for chemical actinometry (Parker 1953). Accurate values of quantum efficiency have been determined at twelve wavelengths between 254 and 578 m
μ
, and the... ...
Tập 235 Số 1203 - Trang 518-536 - 1956
Electromagnetic diffraction in optical systems, II. Structure of the image field in an aplanatic systemAn investigation is made of the structure of the electromagnetic field near the focus of an aplanatic system which images a point source. First the case of a linearly polarized incident field is examined and expressions are derived for the electric and magnetic vectors in the image space. Some general consequences of the formulae are then discussed. In particular the symmetry properties of... ...
Tập 253 Số 1274 - Trang 358-379 - 1959