A combined study of the crystalline structure, the chemical interaction, and diffusion processes of the substrate/layer interface of amorphous-carbon hard coatings is presented. The structure of the coatings and their gradient layer interface to a chromium buffer layer has been investigated on two substrates @Si~100! and tool steel# using x-ray diffraction ~XRD!. Chemical interaction and diffus...

Electroosmotic flow (EOF) is one of the fundamental processes affecting both resolution and separation times in capillary zone electrophoresis (CZE). EOF is a function of pH and buffer composition (zeta potential) in bare-silica capillaries at any pH above 3 and runs in the cathodal direction, decreasing the effective separation length for cationic species. On the other hand, the absence of EOF...

It is well known that biochemical reactions take place in buffered media and that minor changes in hydrogen-ion concentration can affect profoundly the course of reactions. In the blood of man a variation of more than ±0.1 pH from the normal 7.4 is considered pathological, and a change greater than ±0.4 pH is usually fatal. The pH of the blood is maintained within these narrow limits by a syste...

The IEEE 802.11e standard revises the Medium Access Control (MAC) layer of the former IEEE 802.11 standard for Quality-of-Service (QoS) provision in the Wireless Local Area Networks (WLANs). The Enhanced Distributed Channel Access (EDCA) function of 802.11e defines multiple Access Categories (AC) with AC-specific Contention Window (CW) sizes, Arbitration Interframe Space (AIFS) values, and Tran...

Multi-hydrogenated compounds detection based on photoacoustic (PA) spectroscopy is reported. Three near-infrared semiconductor lasers are used with a resonant PA cell operated in its first longitudinal mode to monitor methane, water vapour and hydrogen chloride in the parts per million range. The design of our cell results from simulations performed in order to optimise its performances. Influe...

The IEEE 802.11e standard revises the Medium Access Control (MAC) layer of the former IEEE 802.11 standard for Quality-of-Service (QoS) provision in the Wireless Local Area Networks (WLANs). The Enhanced Distributed Channel Access (EDCA) function of 802.11e defines multiple Access Categories (AC) with AC-specific Contention Window (CW) sizes, Arbitration Interframe Space (AIFS) values, and Tran...

We consider a fluid queue where the input process consists of N identical sources that turn on and off at exponential waiting times. The server works at the constant rate c and an on source generates fluid at unit rate. This model was first formulated and analyzed by Anick, Mitra and Sondhi in [3]. We obtain an alternate representation of the joint steady state distribution of the buffer conten...

We describe automated column-switching high-performance liquid chromatography for determining nine tricyclic and tetracyclic antidepressants (TCAs) and their metabolites in human serum. TSKgel ODS-80TM and TSKprecolumn PW (Tosoh Co., Tokyo) are used in the analytical column and the precolumn, respectively. A 200-microL serum sample is directly injected onto the precolumn. After washing the seru...

This is a method for the simultaneous determination of neoptenn, a product of interferon-gamma-activated macrophages, and creatininein serum.Acidified,butnotdeproteinized serum is applied to a 4-propylbenzene sulfonic acidmodified silica sorbentcartridge, whichquantitativelyretains the analytes but not the serum proteins.The retained analytes are then eluted from the cartridge directly onto the...

This article deals with the performance of Bluetooth scatternets in a real-life environment where different queues are implemented with finite buffers. Finite buffer size will introduce packet blocking at different queues along the packet path, which in turn causes changes in effective traffic load as well as retransmissions and ultimately affects end-to-end packet delays. The authors assume th...