Hyper-resolution indoor channel impulse responses: multipathcomponents and k-factors

A hyper-resolution method has been used to estimate the wideband indoor channel impulse response at 1.3 GHz in a variety of environments within a building. The number of multipath components N and the Ricean k-factor have been investigated. The effect of the presence of people has also been monitored. The results show that if a 30 dB impulse response dynamic range threshold is considered. A value of N less than 7 is applicable to all cases for >90% of the time. It is also shown that the k-factor can be reliably estimated using only the three strongest components     

Phototoxic Activity and DNA Interactions of Water‐Soluble Porphyrins and Their Rhenium(I) Conjugates

In the search for alternative photosensitizers for use in photodynamic therapy (PDT), herein we describe two new water‐soluble porphyrins, a neutral fourfold‐symmetric compound and a +3‐charged tris‐methylpyridinium derivative, in which either four or one [1,4,7]‐triazacyclononane (TACN) units are connected to the porphyrin macrocycle through a hydrophilic linker; we also report their corresponding tetracationic Re^I conjugates. The in vitro (photo)toxic effects of the compounds toward the human cell lines HeLa (cervical cancer), H460M2 (non‐small‐cell lung carcinoma), and HBL‐100 (non‐tumorigenic epithelial cells) are reported. Three of the compounds are not cytotoxic in the dark up to 100 μm , and the fourfold‐symmetric couple revealed very good phototoxic indexes (PIs). The intracellular localization of all derivatives was studied in HeLa cells by confocal fluorescence microscopy. Although low nuclear localization was observed for some of them, it still prompted us to investigate their capacity to bind both quadruplex and duplex DNA; we observed significant selectivity in the tris‐methylpyridinium derivatives for G‐quadruplex interactions.     

Determination of dislocation density from hardness measurements in metals

For the first time the Nix-Gao model for indentation size effect (ISE) is used to estimate the dislocation density in a metal. The estimate of dislocation density obtained by this method, using Ni as a case study, is compared with the values obtained from direct observation by transmission electron microscopy. It is shown that the estimate of dislocation density from indentation hardness measurements, adjusted by the Nix-Gao model, gives values consistent with those obtained by TEM, provided that the proper procedures to minimize errors are adopted. Although the direct observation of dislocations by TEM gives additional structural information, the indirect method to estimate dislocation density based on hardness measurements is more efficient, since the sample preparation method, measurement procedure and analysis of results are easier and faster.     

Microstructure and properties of laser direct deposited CuNi17A13Fe1.5Cr ahoy

Thin walls of a copper-base alloy with the nominal composition CuNi17A13Fe1.5Cr were successfully prepared by laser direct deposition additive manufacturing.The microstructure,as revealed by optical and scanning electron microscopy,indicated that the deposited material was fully dense and with a dendritic microstructure.The dendrites are parallel to the build-up direction,which is also the heat conduction direction during deposition.X-ray diffraction analysis results show that the deposited material is composed of a single phase and a copper-based solid solution.Some precipitate particles of metal silicides were observed in the interdendritic region by scanning electron microscopy.The ultimate tensile strength along the laser scanning direction reaches 735 MPa.The hardness is about Hvo.1 300.     

Polymyalgia syndrome and atrial myxoma

We present a case of polymyalgia-like syndrome in a 62-years-old woman with four month history of severe headache, muscular claudication, asthenia, normochromic, normocytic anaemia and elevation of erytrocyte sedimentation rate. A diagnosis of giant left atrial myxoma was made brought about by thoracoabdominal magnetic resonance. Their surgical exeresis was followed by gradual disappearance of symptoms and normalization of laboratory parameters.     

Formaldehyde biodegradation in the presence of methanol under denitrifying conditions

Simultaneous formaldehyde and methanol biodegradation and also denitrification were studied in batch assays and in a continuous laboratory‐scale reactor. In batch assays, high formaldehyde concentrations (up to 1360 mg dm^?3) were removed under anoxic conditions in the presence of methanol. It was found that formaldehyde biodegradation produced methanol and formic acid as products. The denitrification process was affected by the initial formaldehyde concentration. In the continuous reactor, the biodegradation of different concentrations of formaldehyde (1500–275 mg dm^?3) and methanol (153–871 mg dm^?3) took place, maintaining the organic loading rate at 0.84 g COD dm^?3 d^?1 (COD/N 4). However, each increase in the methanol concentration in the influent caused a decrease in the denitrification level. An adaptation period to methanol was necessary before the denitrification percentage could be recovered. In contrast with batch assays, in the continuous reactor methanol and formic acid were not detected in the effluent. Moreover, in the continuous reactor the denitrification percentages were higher and the nitrite accumulation was lower. Copyright © 2005 Society of Chemical Industry     

Scintillation limitations on the 2nd-phase-difference range measurement

The letter investigates the effect of the partly random character of ?2? on the 2nd-phase-difference range-measurement technique devised by Burns and Fremow.     

Study of pulsed-current loading of direct methanol fuel cells using a new time-domain model based on bi-functional methanol oxidation kinetics

This work describes a non-linear time-domain model of a direct methanol fuel cell (DMFC) and uses that model to show that pulsed-current loading of a direct methanol fuel cell does not improve average efficiency. Unlike previous system level models, the one presented here is capable of predicting the step response of the fuel cell over its entire voltage range. This improved model is based on bi-functional methanol oxidation reaction kinetics and is derived from a lumped, four-step reaction mechanism. In total, six states are incorporated into the model: three states for intermediate surface adsorbates on the anode electrode, two states for the anode and cathode potentials, and one state for the liquid methanol concentration in the anode compartment. Model parameters were identified using experimental data from a real DMFC. The model was applied to study the steady-state and transient performance of a DMFC with the objective to understand the possibility of improving the efficiency of the DMFC by using periodic current pulses to drive adsorbed CO from the anode catalyst. Our results indicate that the pulsed-current method does indeed boost the average potential of the DMFC by 40 mV; but on the other hand, executing that strategy reduces the overall operating efficiency and does not yield any net benefit.