Publisher’s Note: Chips—A New Open Access Journal on Integrated Circuit

A chip is a set of electronic circuits on one small flat piece (or “chip”) of semiconductor material [...]

Cherry Maps with Different Critical Exponents: Bifurcation of Geometry

We consider order-preserving $C^3$ circle maps with a flat piece, irrational rotation number and critical exponents $(l_1, l_2)$. We detect a change in the geometry of the system. For $(l_1, l_2) \in [1, 2]^2$ the geometry is degenerate and becomes bounded for $(l_1, l_2) \in [2, \infty)^2 \backslash \{(2, 2)\}$. When the rotation number is of the form $[abab \ldots]$; for some $a, b \in \mathbb{N}^*$, the geometry is bounded for $(l_1, l_2)$ belonging above a curve defined on $]1, +\infty[^2$. As a consequence, we estimate the Hausdorff dimension of the nonwandering set $K_f=\mathcal{S}^1\backslash \bigcup^\infty_{i=0}f^{-i}(U)$. Precisely, the Hausdorff dimension of this set is equal to zero when the geometry is degenerate and it is strictly positive when the geometry is bounded.

Finding Fifths in Origami

Paper folding, or origami in Japanese, is a traditional craft that has been enjoyed by both children and adults for hundreds of years. An origami is typically made with a square piece of paper and no additional tools. A series of folds can transform a flat piece of square paper into an everyday object such as a bird, a boat, or a flower. Aligning vertices or edges makes a crease, and as new creases are made, they and their intersections become additional matching targets used to create new folds.

Copper Alloy and Raw Copper Waste: Descriptions (JPN)

Analyses of the following items are given in microfiche Table 6, where details of sample and context numbers are also listed. See also full catalogue of metallurgical debris in Table 2.44. Irregular flat piece of bronze, 13x12 mm; as cast medium tin bronze; corroded away; dendrite arm spacing = 30 40μ, suggesting a moderate cooling rate; interdendritic distribution of sulphide clusters, all basically Cu2S, although some contain a few percent iron; massive surface corrosion with islands of α and δ; fragments of charcoal and small areas of typical melting slag adhering, some possibly having originally floated on the surface of a melt. It is reasonable to suppose that this piece could have been the residue left in a crucible after a pour and had set there and been knocked out later, with charcoal and dross still embedded in the metal. See also analysis of sulphide inclusions in microfiche Table 7.

Notes on some Specimens of Rocks from the Antarctic Regions

Towards the end of the year 1893, I received from Captain Thomas Robertson of Dundee, master of the steamship “Active,” a number of specimens of rocks which he had collected in the Antarctic regions during a sealing expedition. In letters to me he gave the following particulars regarding these specimens:—“They were all taken from one place in Dundee Island. We had not time to land and take specimens from other parts. Dundee Island, so named by me, is a separate piece of land, close to Joinville Island, and all the stones I sent you were picked up on a beach at its south-west end. I had a boat sealing on Joinville Island, but they brought no specimens of rock on board. The round flat piece of light-coloured granite I broke off a piece the size of a man's head, the day I sent off the box to you. The small piece of blue basaltic rock I broke off at the same time, not to make the box too heavy. You have all the others as they were found. The southwest end of Dundee Island is a long low point which I named ‘Welchness.’ There are high cliffs up from the ness, from which the pieces of granite could have come, or they might have been carried by the ice.

II. Measurement of the electromotive force required to produce a spark in air between parallel metal plates at different distances

The electrometers used in this investigation were the absolute electrometer and the portable electrometer described in my last communication to the Royal Society, and the operations were ex­ecuted by the same gentlemen, Mr. Smith and Mr. Ferguson. The conductors between which the sparks passed were two unvarnished plates of a condenser, of which one was moved by a micrometer screw, giving a motion of 1/25 of an inch per turn, and having its head divided into 40 equal parts of circumference. The readings on the screw-head could be readily taken to tenth parts of a division, that is to say, to 1/10000 of an inch on the distance to be measured. The point from which the spark would pass in successive trials being somewhat variable and often near the edges of the discs, a thin flat piece of metal, made very slightly convex on its upper surface like an extremely flat watch glass, was laid on the lower plate. It was then found that the spark always passed between the crown of this con­vex piece of metal and the flat upper plate. The curvature of the former was so small, that the physical circumstances of its own elec­trification near its crown, the opposite electrification of the opposed flat surface in the parts near the crown of the convex, and the electric pressure on or tension in the air between them could not, it was supposed, differ sensibly from those between two plane conducting surfaces at the same distance and maintained at the same differenee of potentials.