Sensitive Kinetic-Spectrophotometric Determination of Trace Amounts of Periodate Ion

A simple, precise, sensitive and accurate method was developed for rapid determination of trace quantities of periodate. The method is based on the accelerating effect of periodate on the reaction of bromate and hydrochloric acid in the presence of hydrazine. The decolorization of methyl orange with the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. Periodate could be determined in the concentration ranges of 0.02–1.5 g/mL. The relative standard deviation for ten replicate determinations of 0.3 g/mL of periodate was 1.12%. The method was applied to the determination of periodate in water samples and indirect determination of ethylene glycol in gasoline and glycerol in vegetable oil via Malaprade reaction with satisfactory results.     

The -theory of toric manifolds

Toric manifolds, a topological generalization of smooth projective toric varieties, are determined by an -dimensional simple convex polytope and a function from the set of codimension-one faces into the primitive vectors of an integer lattice. Their cohomology was determined by Davis and Januszkiewicz in 1991 and corresponds with the theorem of Danilov-Jurkiewicz in the toric variety case. Recently it has been shown by Buchstaber and Ray that they generate the complex cobordism ring. We use the Adams spectral sequence to compute the -theory of all toric manifolds and certain singular toric varieties.

     

A Dielectric Chirped Layered Mirror for Optical Telecommunication Wavelengths

We describe in this paper a design procedure for omnidirectional high reflectors with wide bandwidths for optical telecommunication bands. From the numerical results achieved by the transfer matrix method, it is found that a partial omnidirectional high-reflector covering the optical telecommunication wavelengths 1.3 and 1.55 μm is obtained for a partially deformed quarter-wave stack air/H(LH)¹⁵/glass by using the tellurium as a material of high refractive index (n _H = 4.6). The partially deformed stack is a periodic system deformed by a power law y = x ^1+k. Here y is the coordinates of the deformed object, x is the coordinates of the periodic stack and k is the coefficient defining the deformation degree. The study of this system leads to an omnidirectional high reflector band covering the optical telecommunication wavelengths 1.3 and 1.55 μm for k = 0.2.     

Armatans A and B,New Antimicrobial Isoflavans from Colutea armata

Chemistry of Natural Compounds - Armatans A (1) and B (2), new isoflavans, have been isolated from the EtOAc-soluble fraction of the MeOH extract of Colutea armata Hemsl. & Lace, along with...     

Nuclear model calculation on charge particle induced reaction on Rb and Kr targets and targetry for 82Sr production

The ⁸²Sr/⁸²Rb radionuclide generator is used very commonly in positron emission tomography. ALICE/ASH and TALYS 1.0 codes were used to calculate excitation functions for proton, alpha and ³He induced on various targets that lead to produce ⁸²Sr radioisotope using intermediate energy accelerators. Recommended thickness of the targets according to SRIM code was premeditated. The application of those data, particularly in the calculation of integral yields, is discussed and theoretical integral yields for any reaction were computed. To consider precision of TALYS 1.0 code calculations, ⁸⁵Rb(p,4n)⁸²Sr process was determined as most interesting one due to radionuclide purity. The TALYS 1.0 code predicts a maximum cross-section of about 130 mb at 47 MeV for this reaction. Rubidium chloride deposition on copper substrate was carried out via sedimentation method in order to produce ⁸²Sr. 2.98 g RbCl, 1.043 g ethyl cellulose, 10 mL acetone were used to prepare a layer of enriched rubidium chloride of 11.69 cm² area and 0.34 g/cm² thickness.     

Production study of high specific activity NCA Re-186g by proton and deuteron cyclotron irradiation

Very high specific activity (A_S) ^186gRe could be produced by either proton or deuteron cyclotron irradiation on highly enriched ¹⁸⁶W target in no-carrier-added (NCA) form, leading to a A_S very close to the theoretical carrier free (CF) value of 6.88 GBq μg⁻¹. Thick Target Yields (TTYs), obtained irradiating both thick metal W targets of natural isotopic composition and highly enriched powdered ¹⁸⁶W targets, were measured at different particles energies taking into account high accuracy and precision. The evaluation of radionuclidic purities of ^186gRe obtained activating highly enriched ¹⁸⁶W by both p and d were also carried out and accurately compared. The thin-target excitation functions for all Re (A = 181, 182, 183, 184, 186 and their metastable levels), and W and Ta coproduced radionuclides will be presented elsewhere in deep details.     

Fuzzy delay differential equations

In this paper, we prove a local existence and uniqueness result for fuzzy delay differential equations driven by Liu process. We also establish continuous dependence of solution with respect to initial data.     

The effect of parasitic boron doping on P-type piezoresistors

Absolute piezoresistive pressure sensors often use direct wafer bonding of SOI with the etched bulk silicon to provide us with sensitive membranes and sealed cavities. The advantage of such a process is that we can easily obtain a thin, monocrystalline silicon membrane with controlled thickness and a vacuum sealed cavity. However, few works have been reported on the electrical quality of this N-type membrane and its influence on performance of the P-type gauges. The problem of parasitic Boron appearance at the Si/SiO₂ interface was only recently shown in BESOI wafers, but it becomes much more significant when creating the component at the bottom side of the device layer, like in the case of an absolute piezoresistive pressure sensor.