On Proving Too Much

It is quite common to object to an argument by saying that it “proves too much.” In this paper, I argue that the “proving too much” charge can be understood in at least three different ways. I explain these three interpretations of the “proving too much” charge. I urge anyone who is inclined to level the “proving too much” charge against an argument to think about which interpretation of that charge one has in mind.     

Under-microscope Mechanical Pulse System for Studying Deformation Processes at High Strain Rates

Experimental Mechanics - We present a miniature experimental system that allows real time optical observation of deformation processes in materials. The system can apply controllable force pulses...     

Separation of polar betalain pigments from cacti fruits of Hylocereus polyrhizus by ion-pair high-speed countercurrent chromatography

Polar betacyanin pigments together with betaxanthins from ripe cactus fruits of Hylocereus polyrhizus (Cactaceae) were fractionated by means of preparative ion-pair high-speed countercurrent chromatography (IP-HSCCC) also using the elution–extrusion (EE) approach for a complete pigment recovery. HSCCC separations were operated in the classical ‘head-to-tail’ mode with an aqueous mobile phase. Different CCC solvent systems were evaluated in respect of influence and effectiveness of fractionation capabilities to separate the occurring pigment profile of H. polyrhizus. For that reason, the additions of two different volatile ion-pair forming perfluorinated carboxylic acids (PFCA) were investigated. For a direct comparison, five samples of Hylocereus pigment extract were run on preparative scale (900 mg) in 1-butanol–acetonitrile–aqueous TFA 0.7% (5:1:6, v/v/v) and the modified systems tert.-butyl methyl ether–1-butanol–acetonitrile–aqueous PFCA (2:2:1:5, v/v/v/v) using 0.7% and 1.0% trifluoroacetic acid (TFA) or heptafluorobutyric acid (HFBA) in the aqueous phase, respectively. The chemical affinity to the organic stationary CCC solvent phases and in consequence the retention of these highly polar betalain pigments was significantly increased by the use of the more lipophilic fluorinated ion-pair reagent HFBA instead of TFA. The HFBA additions separated more effectively the typical cacti pigments phyllocactin and hylocerenin from betanin as well as their iso-forms. Unfortunately, similar K_D ratios and selectivity factors α around 1.0–1.1 in all tested solvent systems proved that the corresponding diastereomers, 15S-type pigments cannot be resolved from the 15R-epimers (iso-forms). Surprisingly, additions of the stronger ion-pair reagent (HFBA) resulted in a partial separation of hylocerenin from phyllocactin which were not resolved in the other solvent systems. The pigments were detected by means of HPLC-DAD and HPLC-electrospray ionization–MS using also authentic reference materials.     

On low discrepancy sequences and low discrepancy ergodic transformations of the multidimensional unit cube

In this paper we describe a third class of low discrepancy sequences. Using a lattice Γ ? ? ^s , we construct Kronecker-like and van der Corput-like ergodic transformations T _1,Γ and T _2,Γ of [0, 1) ^s . We prove that for admissible lattices Γ, (T _ν,Γ ⁿ (x))_n≥0 is a low discrepancy sequence for all x ∈ [0, 1) ^s and ν ∈ {1, 2}. We also prove that for an arbitrary polyhedron P ? [0, 1) ^s , for almost all lattices Γ ∈ L _s = SL(s,?)/SL(s, ?) (in the sense of the invariant measure on L _s ), the following asymptotic formula

$\# \{ 0 \le n < N:T_{v,\Gamma }^n(x) \in P\} = NvolP + O({(\ln N)^{s + \varepsilon }}),N \to \infty$

holds with arbitrary small ? > 0, for all x ∈ [0, 1) ^s , and ν ∈ {1, 2}.

     

Central limit theorems for the ergodic adding machine

In this paper we find a second class of sequences of random numbers (x _n ) _n=1 ^∞ (the orbit of the ergodic adding machine) such that the corresponding sequences of zeros and ones 1_[0,y](x _n) (n=1,2,...,N) satisfy Central Limit Theorems with extremely small standard deviationσ _N=O(√logN), instead ofO(√N), asN → ∞. Dedicated to Professor Benjamin Weiss on the occasion of his 60^th birthday.     

Two-slab all-optical spring

It is demonstrated that a waveguide consisting of two dielectric slabs may become an all-optical spring when guiding a superposition of two transverse evanescent modes. Both slabs are transversally trapped in stable equilibrium due to the optical forces developed. A condition for stable equilibrium on the wavenumbers of the two modes is expressed analytically. The spring constant characterizing the system is shown to have a maximal value as a function of the equilibrium distance between the slabs and their width.     

Controlling Field‐Effect Transistor Biosensor Electrical Characteristics Using Immunosorbent Assay

A method to modulate the signal of field‐effect transistor biosensors using an immunosorbent assay is described. A model system is used to show that binding of a secondary antibody, to which highly charged gold colloids are attached, to an analyte on the device floating gate can be used to induce strong electrostatic effects, which affect the device threshold voltage and source‐drain current. This process may be used for signal amplification, with the secondary binding specificity allowing for improved signal to noise ratio, which is of great importance for early disease detection.     

Synthesis and characterization of spherical and hemispherical polyepoxide micrometer‐sized particles of narrow size distribution by a single‐step swelling of uniform polystyrene template microspheres with glycidyl methacrylate

Polystyrene template microspheres of narrow size distribution were prepared by dispersion polymerization of styrene in a mixture of ethanol and 2‐methoxy ethanol. Spherical and hemispherical polystyrene/poly(glycidyl methacrylate) microspheres of narrow size distribution were prepared by a single‐step swelling of the polystyrene template microspheres with the swelling solvent monomer glycidyl methacylate, followed by polymerization of the monomer within the swollen template microspheres at 73 °C. Uniform polystyrene/poly(glycidyl methacylate‐ethylene glycol dimethacrylate) polyepoxide composite microspheres were synthesized similarly, substituting glycidyl methacylate for glycidyl methacylate and ethylene glycol dimethacrylate. Uniform crosslinked poly(glycidyl methacylate‐ethylene glycol dimethacrylate) polyepoxide microspheres have been prepared by dissolution of the PS template polymer of the former composite microspheres. Particles with different properties, for example size, size distribution, shape, surface morphology, surface area, and so forth, were prepared by changing various parameters belonging to the swelling and/or polymerization steps, for example, volume of the swelling monomer/s and/or the swelling solvent dibutyl phthalate. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4612–4622, 2007     

Distribution of Mn Atoms in a Substitutional bcc-FeMn Solid Solution

Hyperfine Interactions - We have taken conversion electron Mössbauer spectra to Fe–Mn alloys with 7.5, 10.5 and 13.7 wt.% Mn, that allowed us to obtain the relative fractions of the...     

Advanced features of SCD’s uncooled detectors

SCD has recently presented an uncooled detector product line based on the high-end VO_x bolometer technology. The first FPA launched, BIRD, is a 384×288 (or 320×240) configurable format with 25 μm pitch. Typical NETD values for these FPAs range at 50 mK with an F/1 aperture and 60 Hz frame rate. These detectors also exhibit a relatively fast thermal time constant of approximately 10 ms. In this paper we elaborate on the special advanced features that were incorporated within the ROIC and supporting algorithms. In this framework we have addressed two important issues: the power consumption and the time span between shutter activations. Minimum power consumption is a critical issue for many un-cooled applications. SCD has addressed this by introducing the “power-save” concept accompanied with flexible dilution architecture. The paper will present recent results exhibiting the various advantages. One of the limiting factors on the performance of uncooled detectors is their vulnerability to ambient drift. Usually, even minor temperature fluctuations are manifested as high residual non-uniformity (RNU) or fixed pattern noise (FPN). As a result frequent shutter operations must be applied, with the risk of blocking the scenery in critical time frames. The challenge is thus twofold: to increase the time span between shutter corrections and achieve better control of its activation. For this purpose BIRD provides two complementing mechanisms: A real-time (frame-by-frame) ambient drift compensation accompanied by an RNU prediction mechanism. The paper will discuss these features in detail and present illustrative system implementations. The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570N (2005).