Planar sulfur-doped silicon detectors for high-speed infrared thermography

Planar extrinsic sulfur-doped silicon detectors for infrared (IR) semiconductor-discharge gap image converters intended for use in high-speed thermography of remote objects have been developed. The detectors were fabricated by high-temperature diffusion of sulfur into silicon wafers from the vapor phase. The dependence of doping efficiency on the sulfur vapor pressure in the course of diffusion was analyzed. The detector fabrication technology was optimized to meet the specific requirements for their operation in the microdischarge devices considered. The detectors were tested in a laboratory setup comprising a blackbody source of IR light, an image converter, and a pulsed CCD camera for recording the converted images. The converter equipped with the detector can provide imaging of objects heated to a temperature, T_min ≈ 200 °C, with a temporal resolution on the order of 10^?6 s and spatial resolution of about 5 lines/mm.     

Weak Convergence of Greedy Algorithms in Banach Spaces

We study the convergence of certain greedy algorithms in Banach spaces. We introduce the WN property for Banach spaces and prove that the algorithms converge in the weak topology for general dictionaries in uniformly smooth Banach spaces with the WN property. We show that reflexive spaces with the uniform Opial property have the WN property. We show that our results do not extend to algorithms which employ a ‘dictionary dual’ greedy step.     

Behavior of rate coefficients for ion-ion mutual neutralization, 300-550 K

Rate coefficients k(MN) have been measured for a number of anion neutralization reactions with Ar(+) and Kr(+) over the temperature range 300-550 K. For the first time, the data set includes anions of radicals and other short-lived species. In the present paper, we review these results and make note of correlations with reduced mass, electron binding energy of the anion (equivalent to the electron affinity of the corresponding neutral), and temperature, and compare with expectations from absorbing sphere models. An intriguing result is that the data for diatomic anions neutralized by Ar(+) and Kr(+) have k(MN) values close to 3 × 10(-8) cm(3) s(-1) at 300 K, a figure which is lower than those for all of the polyatomic anions at 300 K except for SF(5)(-) + Kr(+). For the polyatomic anions studied here, neutralized by Ar(+) and Kr(+), the reduced mass dependence agrees with theory, on average, but we find a stronger temperature dependence of T(-0.9) than expected from the theoretical E(-0.5) energy dependence of the rate coefficient at thermal energies. The k(MN) show a weak dependence on the electron binding energy of the anion for the polyatomic species studied.     

Electron spin resonance of nanoporous carbon with embedded cobalt clusters

Cobalt clusters were embedded into a nanoporous carbon powder (with pores about 2 nm in size) prepared from a B₄C carbide powder. Electron spin resonance (ESR) measurements were carried out within a broad temperature range. At all temperatures, the ESR spectrum consisted of two overlapping resonance Lorentzian lines. The temperature dependences of the integrated intensities and linewidths and of the resonance fields were determined. A theoretical analysis of these dependences shows that they can be described in terms of the theory of a disordered magnetic medium with two spin systems with different properties.     

Families of Spectral Sets for Bernoulli Convolutions

We study the harmonic analysis of Bernoulli measures μ _λ , a one-parameter family of compactly supported Borel probability measures on the real line. The parameter λ is a fixed number in the open interval (0,1). The measures μ _λ may be understood in any one of the following three equivalent ways: as infinite convolution measures of a two-point probability distribution; as the distribution of a random power series; or as an iterated function system (IFS) equilibrium measure determined by the two transformations λ(x±1). For a given λ, we consider the harmonic analysis in the sense of Fourier series in the Hilbert space L ²(μ _λ ). For L ²(μ _λ ) to have infinite families of orthogonal complex exponential functions e ^2πis(⋅), it is known that λ must be a rational number of the form \fracm2n\frac{m}{2n}, where m is odd. We show that L²(m_\frac12n)L^{2}(\mu_{\frac{1}{2n}}) has a variety of Fourier bases; i.e. orthonormal bases of exponential functions. For some other rational values of λ, we exhibit maximal Fourier families that are not orthonormal bases.     

Reactivity ratios and copolymerization parameters for copolymers incorporating n-octadecyl acrylate and N-n-octadecylacrylamide

Monomer reactivity ratios and copolymerization parameters were determined for n-octadecyl acrylate and N-n-octadecylacrylamide with several monomers not previously reported. Values of Q and e for the long-chain acrylate now agreed more closely than before with the average of values for the lower acrylate homologs. The average polarity parameter for N-n-octadecylacrylamide still showed more electron withdrawal from the double bond (e = 0.42) than was expressed by the average literature value (e = ?0.10) for N-n-octylacrylamide. Because penultimate effects were absent in this work, the reason for the discrepancy seems to reside in the copolymer analysis. Reactivity ratios for oleyl and octadecyl acrylate with methyl methacrylate were similar. Coefficients for the relation between overall rates of copolymerization and composition were obtained on some systems by curve fitting with a computer. They generally showed a slight minimum.     

Analysis of HIV/AIDS Epidemic and Socioeconomic Factors in Sub-Saharan Africa

Sub-Saharan Africa has been the epicenter of the outbreak since the spread of acquired immunodeficiency syndrome (AIDS) began to be prevalent. This article proposes several regression models to investigate the relationships between the HIV/AIDS epidemic and socioeconomic factors (the gross domestic product per capita, and population density) in ten countries of Sub-Saharan Africa, for 2011–2016. The maximum likelihood method was used to estimate the unknown parameters of these models along with the Newton–Raphson procedure and Fisher scoring algorithm. Comparing these regression models, there exist significant spatiotemporal non-stationarity and auto-correlations between the HIV/AIDS epidemic and two socioeconomic factors. Based on the empirical results, we suggest that the geographically and temporally weighted Poisson autoregressive (GTWPAR) model is more suitable than other models, and has the better fitting results.     

Preclinical Evaluation of Cetuximab and Benzoporphyrin Derivative-Mediated Intraperitoneal Photodynamic Therapy in a Canine Model

Peritoneal carcinomatosis (PC) can occur as an advanced consequence of multiple primary malignancies. Surgical resection, radiation or systemic interventions alone have proven inadequate for this aggressive cancer presentation, since PC still has a poor survival profile. Photodynamic therapy (PDT), in which photosensitive drugs are exposed to light to generate cytotoxic reactive oxygen species, may be an ideal treatment for PC because of its ability to deliver treatment to a depth appropriate for peritoneal surface tumors. Additionally, epidermal growth factor receptor (EGFR) signaling plays a variety of roles in cancer progression and survival as well as PDT-mediated cytotoxicity, so EGFR inhibitors may be valuable in enhancing the therapeutic index of intraperitoneal PDT. This study examines escalating doses of benzoporphyrin derivative (BPD)-mediated intraperitoneal PDT combined with the EGFR-inhibitor cetuximab in a canine model. In the presence or absence of small bowel resection (SBR) and cetuximab, we observed a tolerable safety and toxicity profile related to the light dose received. Additionally, our findings that BPD levels are higher in the small bowel compared with other anatomical regions, and that the risk of anastomotic failure decreases at lower light doses will help to inform the design of similar PC treatments in humans.     

Synthesis of a novel branched cyclophosphazene-PEPA flame retardant and its application on polypropylene

Journal of Thermal Analysis and Calorimetry - A phosphorous–nitrogen containing cyclophosphazene derivative intumescent flame retardant with branched structures, named...