Abstract In this paper the friction and wear of 23CrNi 3 Mo carburized steel under water lubrication were studied. The properties sliding with stainless steel, GCr15, Al 2 O ZrO balls analyzed by tribometer, 3-D topography SEM. results show that compared other materials, carburizing have better tribological properties. Compared , depth is reduced 41% at load N 50% 10 N. range 2N-10N, rate lowes...

Consider lattice paths in Z taking unit steps north (N) and east (E). Fix positive integers r, s and put an equivalence relation on points of Z by letting v, w be equivalent if v − w = `(r, s) for some ` ∈ Z. Call a lattice path valid if whenever it enters a point v with an E-step, then any further points of the path in the equivalence class of v are also entered with an E-step. Loehr and Warri...

Pneumatic muscle is a new type of flexible actuator with advantages in terms of light weight, large output power/weight ratio, good security, low price and clean. In this paper, an ankle rehabilitation robot with two degrees of freedom driven by pneumatic muscle is studied. The force control method with an impedance controller in outer loop and a position inner loop is proposed. The demand of r...

In order to achieve computational workload equivalent to the exhaustive key search of an n-bit key for inversion of RSA or Diffie-Hellman one-way candidate functions the length of their arguments have to have from 10n to 60n bits. One-way functions based on Elliptic Curves in this moment are holding the record, demanding only 2n bits for their arguments. In this paper we propose a definition an...

The Gyárfás tree packing conjecture states that any set of n−1 trees T1, T2, . . . , Tn−1 such that Ti has n− i+ 1 vertices pack into Kn (for n large enough). We show that t = 1 10n 1/4 trees T1, T2, . . . , Tt such that Ti has n− i+ 1 vertices pack into Kn+1 (for n large enough). We also prove that any set of t = 1 10 n1/4 trees T1, T2, . . . , Tt such that no tree is a star and Ti has n− i+ 1...

The exact lengths of linker DNAs connecting adjacent nucleosomes specify the intrinsic three-dimensional structures of eukaryotic chromatin fibers. Some studies suggest that linker DNA lengths preferentially occur at certain quantized values, differing one from another by integral multiples of the DNA helical repeat, approximately 10 bp; however, studies in the literature are inconsistent. Here...

Grinblat (2002) asks the following question in the context of algebras of sets: What is the smallest number v = v(n) such that, if A1, . . . , An are n equivalence relations on a common finite ground set X, such that for each i there are at least v elements of X that belong to Ai-equivalence classes of size larger than 1, then X has a rainbow matching—a set of 2n distinct elements a1, b1, . . ....

Abstract. In 2007, Andrews and Paule introduced the family of functions ∆k(n) which enumerate the number of broken k–diamond partitions for a fixed positive integer k. In that paper, Andrews and Paule proved that, for all n ≥ 0, ∆1(2n + 1) ≡ 0 (mod 3) using a standard generating function argument. Soon after, Shishuo Fu provided a combinatorial proof of this same congruence. Fu also utilized th...

The Coaxial High ENerGy (CHENG) Thruster is a high power coaxial pulsed plasma accelerator that was first proposed in 1970 by D.Y. Cheng. Reported exhaust velocities on the order of 10m/s, thrust densities on the order of 10N/m and low erosion rates make this thruster attractive for a variety of space missions. However, little work has been published since 1970 and the acceleration mechanism is...