We study simplices with integer vertices and no other integer points. Such`hollow' simplices come up in the theory of integer programming, and provide a common formulation of some combinatorial problems, including particular cases of the knapsack or the partition problem. They have been investigated in various contexts and under varying terminology Can thèhollowness' of simplices bèwell-charact...

The compression of 300-fs-long, chirp-free laser pulses at 527 nm down to 30 fs is reported. The laser pulses, originated from a frequency-doubled, mode-locked Nd:glass laser, were compressed by a 0.7-m-long, 150-microm-bore-diameter, argon-filled hollow fiber, and a pair of SF10 prisms with a final energy of 160 microJ. These are the shortest, high energy pulses ever produced by direct pulse c...

This article demonstrates a versatile method to prepare the hollow PbS nanospheres via the template method. First, the latex poly (vinyl benzyl chloride) (PVBC) nanoparticles were synthesized by the radical polymerization, followed by the atom transfer reversible polymerization of lead (II) dimethacrylate (Pb (MA)2) on the surfaces of the latex nanoparticles. Then, the ethanethioamide was react...

Herein, we report an effective, facile, and low-cost route for preparing ZnO hollow microspheres with a controlled number of shells composed of small ZnO nanoparticles. The formation mechanism of multiple-shelled structures was investigated in detail. The number of shells is manipulated by using different diameters of carbonaceous microspheres. The products were characterized by X-ray powder di...

As an intrinsic characteristic of many anticancer drugs, low solubility in physiological conditions limits the usage of these active ingredients in clinics. To overcome this bottleneck, we attempt to design and construct a high-performance magnetic-targeted delivery system based on uniform iron oxide hollow spheres. Via a facile one-pot solvothermal route, well-defined iron oxide hollow spheres...

The 19th harmonic beam divergences from a Ti:sapphire laser generated using a gas jet and 10-mm-long hollow fibers with bore diameters of 300 and 200 μm were investigated. The beam quality factor M(2) of the harmonic beam generated in a 300-μm hollow fiber was found to be better than the gas jet using the phase match including the atomic dipole phase induced by the short trajectory. On the othe...

We demonstrate the formation of hollow nickel germanide nanostructures of Ni-Ge core-shell nanoparticles by solid state reactions. The structural evolutions of nickel germanide hollow nanostructures have been investigated in real-time ultrahigh vacuum transmission electron microscopy (UHV-TEM). Annealed above 450 °C, the nonequilibrium interdiffusion of core and shell species occurred at the in...

Photonic band gap (PBG) dielectric fibers with hollow cores are being studied both theoretically and experimentally for use as laser driven accelerator structures. The hollow core functions as both a longitudinal waveguide for the transverse-magnetic (TM) accelerating fields and a channel for the charged particles. The dielectric surrounding the core is permeated by a periodic array of smaller ...

Rhodoliths are coralline red algal assemblages that commonly occur in marine habitats from the tropics to polar latitudes. They form rigid structures of high-magnesium calcite and have a good fossil record. Here I show that rhodoliths are ecosystem engineers in a high Arctic environment that increase local biodiversity by providing habitat. Gouged by boring mussels, originally solid rhodoliths ...

Hollow nickel silicate nanospheres (NiSiO3 NSs) with hierarchical shells were hydrothermally synthesized by using silica spheres as a template. The NiSiO3 NSs have an average diameter of 250 nm with a shell thickness of 50 nm, and the hierarchical shell consists of a large number of sheets. By taking advantage of the high affinity of Ni(2+) toward histidine-tagged (His-tagged) proteins, hollow ...