466 research outputs found

### On Pair-Particle Distribution in Imperfect Bose Gas

A simple model of estimating the radial distribution function of an imperfect
Bose gas in the ground state is presented. The model is based on
integro-differential equations derived by considering the space boson
distribution in an external field. With the approach proposed, the particular
case of dilute Bose gas is investigated within the hard sphere approximation
and beyond.Comment: 8 pages, LaTEX, no Figures. Submitted to Phys. Lett.

### Comments on "Stability of Tsallis entropy and instabilities of Renyi and normalized Tsallis entropies: A basis for q-exponential distributions"

It is shown that the Renyi entropy is as stable as the Tsallis entropy at
least for Abe-Lesche counterexamples.Comment: 1 pag

### On the Inhibitor for the Corrosion by Hydrochloric Acid on High-Chromium Steels

The action of potassium dichromate as the inhibitor for the corrosion by hydrochloric acid on high-chromium steels was investigated. High-chromium steels were made passive by addition of proper quantities of potassium dichromate in various concentration of hydrochloric acid. But the action of potassium dichromate is cathodic control and anodic inhibitor, therefore, it is a very dangerous inhibitor. The minimum quantity of potassium dichromate required for the complete passive state was proportional to square of specific concentration of chromium in alloys. Molybdenum added to high-chromium steels, so far as it existed in solid solution, was very effective to lower the minimum quantity of potassium dichromate and to prevent perfectly pit or cavity corrosion on high-chromium steels. For instance, the minimum numerical value of potassium dichromate was 100 g per litre for the steel containing 33 per cent chromium, but 0.01 g per litre for the steel containing 33 per cent chromium and 3 per cent molybdenum in 10 per cent of hydrochloric acid. When high-chromium-molybdenum steels were in heterogeneous structure, they became very difficult to get passive state. Tungsten was not so effective as molybdenum with respect to the corrosion resisting properties of high-chromium steels

### A Conjectured Paradigm Shift in 21st Century Mathematics Pedagogy

With greater and greater capacity for automated content delivery, the role of teachers may shift increasingly to providing the human touch in pedagogy such as love for students

### On the Estimation of Commercial Values of Iron Ores

The commercial values of iron ores as the raw. materials for the production of low phosphorus pig iron by means of electric furnaces were estimated by the present writer from the metallurgical point of view. According to the custom in this country, hematite ore composed of 50%Fe, A% SiO_2, B% Al_2O_3, a% CaO, b% MgO, +0.002F(0.33+0.018A-0.013B)+(1.41A-1.09B)D+(8.5+0.45A-0.35B)E+(14.63+0.78A-0.6B) W+0.01(L+P+t)+0.05e yen per ton of ore should be paid for each percent of manganese. (3) If phosphorus content in the ore is below 0.02%, a premium of 0.016F (0.33+0.018A-0.013B)+(11.28A-8.72B)D+(68.0+3.60A-2.80B)E+(117.04+6.24A-4.8B) W+0.08(L+P+t)+0.40e yen per ton of ore should be paid for each 0.005% below 0.02%. (4) When the sulphur content in the ore is above 0.3%, up to 3.5% the maximum allowed, 500 yen or more per ton of ore should be deducted. (5) If the ore is magnetite or limonite, it requires 150 or 120 kWH respectively more than hematite to produce one ton of pig iron. Hence, the extra pay for electric power per ton of magnetite or limonite must be deducted from the price of corresponding hematite ores. In these revision formulas, A is the silica content in percent in the ore, B the sum of CaO and MgO content in percent in the ore, D the price of 1 ton of limestone, e the cost of one kilogram of electrode, E the price of 1 kWH of electric power, F the price of one ton of standard iron ore. F_ the price of one ton of 30% manganese ore. L the labour cost per ton of pig iron produced. P the repair cost per ton of pig iron. t the interest per ton of pig iron produced, and W the cost of water granulation of slag per ton of pig iron produced

### Ruedenberg Bond Order as True Resonance-Theoretic Bond Order

This paper describes a few basic characteristics of Ruedenberg bond order from both resonance-theoretic and molecular-orbital-theoretic aspect and manifests its usefulness and validity through illustrative bond order analysis of several regular alternants containing 4n-membered rings. Ruedenberg bond order is shown to be related with resonance structures exactly and to be regared as distributed valence which can be not only fractional but also negative or larger than unity in sharp contrast with Pauling bond order. It is pointed out that Ruedenberg bond order can reflect reactivity-stability characters of regular alternants more sensitively than Coulson bond order, having a close connection to the frontier orbital bond order. Behaviors of Ruedenberg and Pauling bond orders are compared in regular alternants containing 4n-membered rings and Pauling bond order is concluded to be a superfluous concept

### Note on a Relationship between Self-Mutability and Superdelocalizability in Regular Alternants

This note presents a simple theorem expressing superdelocalizabilities solely in terms of site-site mutabilities in regular alternants. The theorem provides an explicit relationship between self-mutability and superdelocalizability and manifests similarities and differences between the two quantities, leading to a concise interpretation on the physical meaning of superdelocalizability. The theorem is also practically useful for estimating superdelocalizabilities from site-site mutabilities. An effective approximation for estimation is examined with numerical examples. Supplementary remarks are added on the expression of superdelocalizabilities between different sites

### Optically-Induced Polarons in Bose-Einstein Condensates: Monitoring Composite Quasiparticle Decay

Nonresonant light-scattering off atomic Bose-Einstein condensates (BECs) is
predicted to give rise to hitherto unexplored composite quasiparticles:
unstable polarons, i.e., local ``impurities'' dressed by virtual phonons.
Optical monitoring of their spontaneous decay can display either Zeno or
anti-Zeno deviations from the Golden Rule, and thereby probe the temporal
correlations of elementary excitations in BECs.Comment: 4 pages, 3 figure

### Wigner Molecules in Nanostructures

The one-- and two-- particle densities of up to four interacting electrons
with spin, confined within a quasi one--dimensional ``quantum dot'' are
calculated by numerical diagonalization. The transition from a dense
homogeneous charge distribution to a dilute localized Wigner--type electron
arrangement is investigated. The influence of the long range part of the
Coulomb interaction is studied. When the interaction is exponentially cut off
the ``crystallized'' Wigner molecule is destroyed in favor of an inhomogeneous
charge distribution similar to a charge density wave .Comment: 10 pages (excl. Figures), Figures available on request LaTe

### Structural Transitions in a Classical Two-Dimensional Molecule System

The ground state of a classical two-dimensional (2D) system with finite
number of charged particles, trapped by two positive impurities charges
localized at a distance (zo) from the 2D plane and separated from each other by
a distance xp are obtained. The impurities are allowed to carry more than one
positive charge. This classical system can form a 2D-like classical molecule
that exhibits structural transitions and spontaneous symmetry breaking as a
function of the separation between the positive charges before it transforms
into two independent 2D-like classical atoms. We also observe structural
transitions as a function of the dielectric constant of the substrate which
supports the charged particles, in addition to broken symmetry states and
unbinding of particles.Comment: 9 pages, 7 figure

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