Gas phase ion mobility measurements can resolve structural isomers for polyatomic ions and provide information about their geometries. A new experimental apparatus for performing high-resolution ion mobility measurements is described. The apparatus consists of a pulsed laser vaporization/desorption source coupled through an ion gate to a 63-cm-long drift tube. The ion gate is a critical compone...

Coronary arterial inflow is impeded and venous outflow is increased as a result of the decrease in coronary vascular volume due to cardiac contraction. We evaluated whether cardiac contraction is influenced by interfering with the changes of the coronary vascular volume over the heart cycle. Length-tension relationships were determined in Tyrode-perfused rat papillary muscle and when coronary v...

.. Purpose: To compare the results of standard dacryocystorhinostomy with the results of dacryocystorhinostomy done with silicon tube stentting of the lacrimal canaliculi. Study design: This is a hospital based, prospective, comparative and interventional study. Setting: Department of Ophthalmology, Allied Hospital Punjab Medical College Faisalabad. Period: January 2006 to December 2006. Method...

To the editor, In addition to reducing weight, bariatric surgery could improve glucose metabolism in patients with type 2 diabetes mellitus [1, 2]. Such actions have mainly been explained by the foregut and the hindgut hypotheses. The foregut hypothesis claims that bariatric surgery removes endogenous substances that cause disturbance in glucose metabolism [3]. The hindgut hypothesis postulates...

The human vocal tract has been successfully modeled as a series of uniform cross-section tubes concatenated end-to-end. Such a model has been part of the study of the human speech generation system for many years. The similarity of the equations for sound propagation in these tubes and transmission line equations has been exploited in articulatory speech synthesis systems. Each section of tube ...

A new non-linear method for design and analysis of solid state power amplifiers is presented and applied to an aluminum gallium nitride, gallium nitride (AlGaN-GaN) high electron-mobility transistor (HEMTs) on silicon-carbide (SiC) substrate for Ku band (12.4 13.6 GHz) applications. With combining output power of 8 transistors, maximum output power of 46.3 dBm (42.6 W), PAE of 43% and linear ga...

The status and performance of the LHCb detector during the physics LHC physics run is described. The LHCb detector has a number of notable features including: 12 micron resolution in the transverse plane on 30-35 track primary vertices, pion and kaon separation from 1 to 100 GeV, and 1 MHz full readout of all subsystems. The detector is being operating above its design luminosity and is compris...

In this paper, a simple method to synthesize silicon carbide (SiC) nanoribbons is presented. Silicon powder and carbon black powder placed in a horizontal tube furnace were exposed to temperatures ranging from 1,250 to 1,500°C for 5-12 h in an argon atmosphere at atmospheric pressure. The resulting SiC nanoribbons were tens to hundreds of microns in length, a few microns in width and tens of na...

Various methods to determine 222Rn concentration in soil gas were tested at two sites with different soil types in a depth of 1 m. They include instantaneous (spot), continuous (real time) and timeaveraging procedures with advective ('active' procedures) or diffusive ('passive' procedures) gas transport from soil to detector: a) active grab-sampling of soil gas from different thin soil gas prob...

The nanocrystalline silicon-germanium films (Si/Ge) and Si/Ge nanotubes have low band gaps and high carrier mobility, thus offering appealing potential for absorbing gas molecules. Interaction between hydrogen molecules and bare as well as functionalized Si/Ge nanofilm and nanotube was investigated using Monte Carlo (MC) and Langevin dynamic (LD) simulation methods. It was found that the bindin...