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Journal articles on the topic "PULSE (Computer file)"
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Zhu, Yu Quan, Zheng Fei Hu, and Bao Ji Ma. "The STM32 and Programmable Power Supply Communication in the ELID Grinding Dynamic Control System." Advanced Materials Research 605-607 (December 2012): 2073–78. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.2073.
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This paper describes based on the STM32 the dynamic control systems of the ELID grinding oxide film growth process. The system’s structure mainly includes the STM32 controller, DC pulse power source, VMOS circuit and optically coupled isolation circuit. The STM32 controller receives the oxide film thickness value from the host computer. According to the oxide film thickness values, the STM32 controller calls the process library automatically. Based on the process library parameters, the timer outputs the PWM square wave which the frequency and duty cycle can be adjusted, and the serial port output message controled DC power output. The PWM square wave is used to control the on-off of the VMOS circuit, which can be used as the DC converter of the programmable DC power supply, and generates high frequency pulse voltage to control the growth rate of the electrolyte. Finally, the experimental results show that DC pulse power supply output values and the expected output value are consistent.
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GUO, ZHONGYI, HAIFENG WANG, ZHENGJUN LIU, SHILIANG QU, JINGMIN DAI, and SHUTIAN LIU. "REALIZATION OF HOLOGRAPHIC STORAGE ON METAL FILM BY FEMTOSECOND LASER PULSES MICROMACHINING." Journal of Nonlinear Optical Physics & Materials 18, no. 04 (December 2009): 617–23. http://dx.doi.org/10.1142/s0218863509004828.
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Optical information has been stored on the metal film by femtosecond laser pulses with the aid of the computer-generated hologram (CGH). The Fourier transform of an object is performed by a computer, and then the resulted complex amplitude distribution is encoded by the detour phase method. The resulted cell-oriented CGH is directly written on the metal film deposited on the glass substrate using femtosecond laser by selective ablation. The object wave has also been reconstructed with high fidelity by using a collimated He-Ne laser beam.
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Pawliszewska, Maria, Dorota Tomaszewska, Grzegorz Soboń, Anna Dużyńska, Mariusz Zdrojek, and Jarosław Sotor. "Broadband Metallic Carbon Nanotube Saturable Absorber for Ultrashort Pulse Generation in the 1500–2100 nm Spectral Range." Applied Sciences 11, no. 7 (April 1, 2021): 3121. http://dx.doi.org/10.3390/app11073121.
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Herein, we report on the possibility of ultrashort laser pulse generation in the broadband spectral range using a saturable absorber based on free-standing metallic carbon nanotube thin film. Erbium, thulium, and holmium-doped all-fiber lasers were mode-locked with a single saturable absorber containing a 300 nm thick material layer. Subpicosecond pulses were generated at 1559, 1938, and 2082 nm. Our work validates the broadband operation of metallic carbon nanotube-based saturable absorbers and highlights the suitable performance of nanomatematerial for ultrafast photonic applications.
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De Lima, Jader A., Sidnei F. Silva, Adriano S. Cordeiro, and Michel Verleysen. "A CMOS/SOI Single-input PWM Discriminator for Low-voltage Body-implanted Applications." VLSI Design 15, no. 1 (January 1, 2002): 469–76. http://dx.doi.org/10.1080/1065514021000012075.
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A CMOS/SOI circuit to decode Pulse-Width Modulation (PWM) signals is presented as part of a body-implanted neurostimulator for visual prosthesis. Since encoded data is the sole input to the circuit, the decoding technique is based on a novel double-integration concept and does not require low-pass filtering. Non-overlapping control phases are internally derived from the incoming pulses and a fast-settling comparator ensures good discrimination accuracy in the megahertz range. The circuit was integrated on a 2 μm single-metal thin-film CMOS/SOI fabrication process and has an effective area of 2 mm2. Measured resolution of encoding parameter α is better than 10% at 6 MHz and VDD = 3.3 V. Idle-mode consumption is 340 μW. Pulses of frequencies up to15 MHz and α =10% can be discriminated for 2.3 V ≤ VDD ≤ 3.3 V. Such an excellent immunity to VDD deviations meets a design specification with respect to inherent coupling losses on transmitting data and power by means of a transcutaneous link.
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Bunting, Peter, John Armston, Richard M. Lucas, and Daniel Clewley. "Sorted pulse data (SPD) library. Part I: A generic file format for LiDAR data from pulsed laser systems in terrestrial environments." Computers & Geosciences 56 (July 2013): 197–206. http://dx.doi.org/10.1016/j.cageo.2013.01.019.
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Ibrahim, Noor M., and Eman K. Hassan. "Structural and Morphological of Pulsed Laser Deposited Magnesium Phthalocyanine (MgPc) Thin Film." Nano Hybrids and Composites 29 (June 2020): 15–21. http://dx.doi.org/10.4028/www.scientific.net/nhc.29.15.
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Magnesium Phthalocyanine (MgPc) was deposited on a glass substrate by pulsed laser deposition (PLD) using Q-Switching Nd: YAG laser with wavelength 1064(nm), (6Hz) Repetition rate, in addition to different laser energies (200,300,400 and 500 mJ) at room temperature under vacuum condition with (10-3torr). All films were annealed at (298K) for 1hour to attain crystallinity. X-ray diffraction of MgPc powder indicated the fact that MgPc crystallizes in polycrystalline with a monoclinic structure While comparing the MgPc of films, it’s found the intensity of characteristic peak is high as the number and energy of laser pulses increase and the crystallize is monoclinic form is observed in β-form. Miller indices, hkl, values for every one of the diffraction peaks in the spectrum of the XRD have been computed. The characteristic peak of Phthalocyanine (MgPc) is found at 2θ value 6.9137o with the hkl value of {100} for both MgPc powder and deposited thin film. The surface morphology of the films showed more uniform sized grains. EDX and FESEM analysis has shown that there has been an enhancement in the crystallinity and surface morphology as a result of the increase of laser energies and for finding the optimum parameters for which film provides more efficient structural characteristics.
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Kadhim, Ali, Paul Harrison, Jake Meeth, Alaa Al-Mebir, Guanggen Zeng, and Judy Wu. "Development of Combinatorial Pulsed Laser Deposition for Expedited Device Optimization in CdTe/CdS Thin-Film Solar Cells." International Journal of Optics 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/1696848.
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A combinatorial pulsed laser deposition system was developed by integrating a computer controlled scanning sample stage in order to rapidly screen processing conditions relevant to CdTe/CdS thin-film solar cells. Using this system, the thickness of the CdTe absorber layer is varied across a single sample from 1.5 μm to 0.75 μm. The effects of thickness on CdTe grain morphology, crystal orientation, and cell efficiency were investigated with respect to different postprocessing conditions. It is shown that the thinner CdTe layer of 0.75 μm obtained the best power conversion efficiency up to 5.3%. The results of this work shows the importance that CdTe grain size/morphology relative to CdTe thickness has on device performance and quantitatively exhibits what those values should be to obtain efficient thin-film CdTe/CdS solar cells fabricated with pulsed laser deposition. Further development of this combinatorial approach could enable high-throughput exploration and optimization of CdTe/CdS solar cells.
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Wang, J. J., A. B. Limanov, Ying Wang, and James S. Im. "Observation of Superheating of Si at the Si/SiO2 Interface in Pulsed-laser irradiated Si Thin Films." MRS Proceedings 1770 (2015): 43–48. http://dx.doi.org/10.1557/opl.2015.727.
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ABSTRACTSubstantial superheating of single-crystal Si films at and near the bottom Si/SiO2 interface was observed. This was accomplished via back-side irradiation of a (100) single-crystal Si film on a quartz substrate using an excimer-laser pulse. The spatiotemporal details of the melting transition were tracked in situ using surface-side and substrate-side transient reflectance measurements, and the one-dimensional thermal profile evolution within the solid film during the heating period was numerically computed using the experimentally extracted temporal profile of the incident beam and temperature-dependent optical and thermal parameters of the materials. A simple lower-bound estimation identifies that superheating in excess of 100 K was attained within Si along the bottom (100)-Si/SiO2 interface even at moderate beam energy densities.
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Chen, Yao, Yao Shan, Huatian Tu, Haotian Zhang, Rong He, Yuxiang Zheng, Rongjun Zhang, Songyou Wang, Jing Li, and Liangyao Chen. "Quality Improvement of Laser-Induced Periodic Ripple Structures on Silicon Using a Bismuth-Indium Alloy Film." Applied Sciences 11, no. 2 (January 11, 2021): 632. http://dx.doi.org/10.3390/app11020632.
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In this work, a new buffer layer material, a bismuth-indium (Bi-In) alloy, was utilized to improve the quality of large-area, laser-induced periodic ripple structures on silicon. Better-defined ripple structures and larger modification areas were obtained at different scanning speeds by pre-depositing a Bi-In film. The single-spot investigations indicated that ripple structures were much easier to form on silicon coated with the Bi-In film under laser fluences of 2.04 and 2.55 J/cm2 at a fixed pulse number of 200 in comparison with on bare silicon. A physical model in terms of the excellent thermal conductivity contributed by the free electrons in the Bi-In film homogenizing the thermal distribution caused by the laser irradiation in the early stage of the formation of laser-induced periodic surface structures was proposed to explain the above phenomena. The results show that the Bi-In film enabled a wider range of laser fluences to generate periodic structures and helped to form regular ripple structures on the silicon. In addition, the modulation effects of the laser fluence and pulse number on surface structures were studied experimentally and are discussed in detail.
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Dunets, Roman, Bogdan Dzundza, Liliia Turovska, Myroslav Pavlyuk, and Omelian Poplavskyi. "Features for the design of a specialized information-measuring system for the study of thermoelectric properties of semiconductors." Eastern-European Journal of Enterprise Technologies 2, no. 5 (110) (April 30, 2021): 23–31. http://dx.doi.org/10.15587/1729-4061.2021.227135.
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Methods for studying thermoelectric parameters of semiconductors that are optimal for the implementation of software and hardware have been analyzed and selected. It is based on the Harman method and its modifications, adapted for pulse measurements, which are convenient to implement on a modern element base. An important advantage of these methods is the absence of the need for accurate measurements of heat fluxes, which greatly simplifies and reduces the time for conducting experimental research. The required operating ranges for the voltage 10 µV–1 V, for the current 10 µA–300 mA and the element base performance at the processing level of 40–200 million samples per second have been determined. Structural and electrical circuits, as well as software for a specialized computer system for studying thermoelectric parameters of both bulk and thin-film thermoelectric materials, and express analysis of the operational characteristics of finished modules have been developed. It has been shown that the proposed scheme copes well with the task. And the use of FPGA and 32-bit microcontrollers provide sufficient processing speed up to 200 MSPS and the necessary synchronization modes for the implementation of the Harman pulse method even when studying films of nanometer thickness. Experimental studies of both bulk thermoelectric modules based on Bi2Te3 and thin-film thermoelectric material based on PbTe have been carried out. The effectiveness of the developed tools and techniques has been shown, which made it possible to more than halve the time for sample preparation and experiment. Based on the presented models, all the main thermoelectric and operational parameters have been determined, in particular, electrical conductivity, Seebeck coefficient, thermal conductivity, thermoelectric figure of merit. As a result of the development of specialized computer tools, it was possible to reduce the labor intensity of the process of measuring the main electrical and operational parameters of semiconductor thermoelectric materials and energy conversion modules based on them, as well as to automate the process of defects identification of thermoelectric modules. The labor intensity of the research process has decreased not only due to the automation of the measurement process, but also due to an optimized technique that allows research on a sample of one configuration, since the manufacture and preparation of samples are the most laborious
Dissertations / Theses on the topic "PULSE (Computer file)"
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Grant, David James. "Bottom-Gate TFTs With Channel Layer Deposited by Pulsed PECVD." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/805.
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Nanocrystalline silicon (nc-Si:H) is a promising material for Thin-Film Transistors (TFTs) offering potentially higher mobilities and improved stability over hydrogenated amorphous silicon (a-Si:H). The slow growth rate of nc-Si:H can be overcome by using pulsed Plasma-Enhanced Chemical Vapour Deposition (PECVD). Pulsed PECVD also reduces powder particle formation in the plasma and provides added degrees of freedom for process optimization. Unlike high frequency PECVD, pulsed PECVD can be scaled to deposit films over large areas with no reduction in performance.
For this thesis, silicon thin films were deposited by the pulsed PECVD technique at a temperature of 150 °C and TFTs were made using this material. Radio Frequency (RF) power and silane (SiH4) flow rate were varied in order to study the effect of different levels of crystallinity on the film.
Raman spectroscopy, Atomic Force Microscope (AFM), X-Ray Diffraction (XRD), electrical conductivity, Hall mobility, optical band gap, and stability under light-soaking were measured using films of two different thicknesses, 50 nm and 300 nm. From the Raman data we see that the 50 nm films deposited with high hydrogen dilution are mostly amorphous, indicating the presence of a thick incubation layer. The 300nm samples deposited with hydrogen dilution, on the other hand, showed very high crystallinity and conductivity, except for 300-2 which was surprisingly, mostly amorphous. AFM and XRD measurements were also performed to confirm the Raman data and get an estimate for the crystallite grain size in the 300 nm samples. The conductivity was measured for all films, and the Hall mobility and carrier concentration was measured for one of the 300 nm films. The thin samples which are mostly amorphous show low conductivity whereas the thick high crystallinity films show high conductivity, and n-type behaviour possibly due to oxygen doping. The optical gap was also measured using Ultra Violet (UV) light and results indicate the possible presence of small crystallites in the 50 nm films. The conductivity's stability under light-soaking was measured to observe the material's susceptibility to degradation, and the 300 nm with high crystallinity were much more stable than the a-Si:H films. All the results of these measurements varied depending on the film and these results are discussed.
Bottom-gate TFTs were fabricated using a pulsed PECVD channel layer and an amorphous silicon nitride (a-SiN:H) gate dielectric. The extracted parameters of one of the best TFTs are μsat ≤ 0. 38 cm2 V-1 s-1, Vt,sat ≥ 7. 3 V, Ion/off > 106, and S < 1 V/decade. These parameters were extracted semi-automatically from the basic Field-Effect Transistor (FET) model using a computer program. Extraction using a more complicated model yielded similar results for mobility and threshold voltage but also gave a large power parameter α of 2. 31 and conduction band tail slope of 30 meV. The TFT performance and material properties are presented and discussed.
On this first attempt at fabricating TFTs using a nc-Si:H channel layer deposited by pulsed PECVD, results were obtained which are consistent with results for low temperature a-Si:H TFTs and previous pulsed PECVD TFTs. The channel layer was mostly amorphous and non-crystalline, possibly due to the amorphous substrate or insufficient hydrogen dilution in the plasma. The 300 nm films showed, however, that high crystallinity material deposited directly on glass can easily be obtained, and this material showed less degradation under light-soaking than the purely amorphous counterpart. Pulsed PECVD is a promising technique for the growth of nc-Si:H and with further materials development and process optimization for TFTs, it may prove to be useful for the growth of high-quality nc-Si:H TFT channel layers.
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Rahman, Khalifa Mohammad Azizur. "Nanocrystalline Silicon Solar Cells Deposited via Pulsed PECVD at 150°C Substrate Temperature." Thesis, 2010. http://hdl.handle.net/10012/5446.
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A series of experiments was carried out to compare the structural and electronic properties of intrinsic nanocrystalline silicon (nc-Si:H) thin films deposited via continuous wave (cw) and pulsed (p)-PECVD at 150°C substrate temperature. Working at this temperature allows for the easy transfer of film recipes from glass to plastic substrates in the future. During the p-PECVD process the pulsing frequency was varied from 0.2 to 50 kHz at 50% duty cycle. Approximately 15% drop in the deposition rate was observed for the samples fabricated in p-PECVD compared to cw-PECVD. The optimum crystallinity and photo (σph) and dark conductivity (σD) were observed at 5 kHz pulsing frequency, with ~10% rise in crystallinity and about twofold rise in the σph and σD compared to cw-PECVD.
However, for both the cw and p-PECVD nc-Si:H films, the observed σph and σD were one to two orders and three orders of magnitude higher respectively than those reported in literature. The average activation energy (EA) of 0.16 ∓ 0.01 eV for nc-Si:H films deposited using p-PECVD confirmed the presence of impurities, which led to the observation of the unusually high conductivity values. It was considered that the films were contaminated by the impurity atoms after they were exposed to air.
Following the thin film characterization procedure, the optimized nc-Si:H film recipes, from cw and p-PECVD, were used to fabricate the absorber layer of thin film solar cells. The cells were then characterized for J-V and External Quantum Efficiency (EQE) parameters. The cell active layer fabricated from p-PECVD demonstrated higher power conversion efficiency (η) and a maximum EQE of 1.7 ∓ 0.06 % and 54.3% respectively, compared to 1.00 ∓ 0.04 % and 48.6% respectively for cw-PECVD. However, the observed η and EQE of both the cells were lower than a reported nc-Si:H cell fabricated via p-PECVD with similar absorber layer thickness.
This was due to the poor Short-circuit Current Density (Jsc), Open-circuit Voltage (Voc), and Fill Factor (FF) of the cw and p-PECVD cells respectively, compared to the reported cell. The low Jsc resulted from the poor photocarrier collection at longer and shorter wavelengths and high series resistance (Rseries). On the other hand, the low Voc stemmed from the low shunt resistance (Rsh). It was inferred that the decrease in the Rsh occurred due to the inadequate electrical isolation of the individual cells and the contact between the n – layer and the front TCO contact at the edge of the p-i-n deposition area. Additionally, the net effect of the high Rseries and the low Rsh led to a decrease in the FF of the cells.
Books on the topic "PULSE (Computer file)"
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D, Keeffe, ed. PULSE, an Ada-based distributed operating system. London: Academic Press, 1985.
Find full textBook chapters on the topic "PULSE (Computer file)"
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Rychkov, Alexander D., and Yurii I. Shokin. "Numerical Modeling of Work of Pulse Aerosol System of Fire Fighting on Computer Clusters." In Notes on Numerical Fluid Mechanics and Multidisciplinary Design, 51–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-17770-5_5.
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Manivannan, T. S., and Meena Srinivasan. "A Novel Design Approach to Implement Multi-port Register Files Using Pulsed-Latches." In Communications in Computer and Information Science, 521–37. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-13-5950-7_44.
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Bhimasingu, Venkataramesh, Nilesh J. Vasa, and I. A. Palani. "Influence of Substrate Temperature, Pressure and Grit Size on Synthesis of SiC Thin Film by Pulsed Laser Deposition Technique." In Communications in Computer and Information Science, 379–88. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-35197-6_42.
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Hardy, Lawrence Harold. "A History of Computer Networking Technology." In Encyclopedia of Multimedia Technology and Networking, Second Edition, 613–18. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-014-1.ch082.
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The computer has influenced the very fabric of modern society. As a stand-alone machine, it has proven itself a practical and highly efficient tool for education, commerce, science, and medicine. When attached to a network—the Internet for example—it becomes the nexus of opportunity, transforming our lives in ways that are both problematic and astonishing. Computer networks are the source for vast amounts of knowledge, which can predict the weather, identify organ donors and recipients, or analyze the complexity of the human genome (Shindler, 2002). The linking of ideas across an information highway satisfies a primordial hunger humans have to belong and to communicate. Early civilizations, to satisfy this desire, created information highways of carrier pigeons (Palmer, 2006). The history of computer networking begins in the 19th century with the invention of the telegraph, the telephone, and the radiotelegraph. The first communications information highway based on electricity was created with the deployment of the telegraph. The telegraph itself is no more than an electromagnet connected to a battery, connected to a switch, connected to wire (Derfler & Freed, 2002). The telegraph operates very straightforwardly. To send a message (electric current), the telegrapher rapidly opens and closes the telegraph switch. The receiving telegraph uses the electric current to create a magnetic field, which causes an observable mechanical event (Calvert, 2004). The first commercial telegraph was patented in Great Britain by Charles Wheatstone and William Cooke in 1837 (The Institution of Engineering and Technology, 2007). The Cooke-Wheatstone Telegraph required six wires and five magnetic needles. Messages were created when combinations of the needles were deflected left or right to indicate letters (Derfler & Freed, 2002). Almost simultaneous to the Cooke-Wheatstone Telegraph was the Samuel F. B. Morse Telegraph in the United States in 1837 (Calvert, 2004). In comparison, the Morse Telegraph was decidedly different from its European counterpart. First, it was much simpler than the Cooke-Wheatstone Telegraph: to transmit messages, it used one wire instead of six. Second, it used a code and a sounder to send and receive messages instead of deflected needles (Derfler & Freed, 2002). The simplicity of the Morse Telegraph made it the worldwide standard. The next major change in telegraphy occurred because of the efforts of French inventor Emile Baudot. Baudot’s first innovation replaced the telegrapher’s key with a typewriter like keyboard. His second innovation replaced the dots and dashes of Morse code with a five-unit or five-bit code—similar to American standard code for information interchange (ASCII) or extended binary coded decimal interchange code (EBCDIC)—he developed. Unlike Morse code, which relied upon a series of dots and dashes, each letter in the Baudot code contained a combination of five electrical pulses. Eventually all major telegraph companies converted to Baudot code, which eliminated the need for a skilled Morse code telegrapher (Derfler & Freed, 2002). Finally, Baudot, in 1894, invented a distributor which allowed his printing telegraph to multiplex its signals; as many as eight machines could send simultaneous messages over one telegraph circuit (Britannica Concise Encyclopedia , 2006). The Baudot printing telegraph paved the way for the Teletype and Telex (Derfler & Freed, 2002). The second forerunner of modern computer networking was the telephone. It was a significant advancement over the telegraph for it personalized telecommunications, bringing the voices and emotions of the sender to the receiver. Unlike its predecessor the telegraph, telephone networks created virtual circuit to connect telephones to one another (Shindler, 2002). Legend credits Alexander Graham Bell as the inventor of the telephone in 1876. He was not. Bell was the first to patent the telephone. Historians credit Italian- American scientist Antonio Meucci as the inventor of the telephone. Meucci began working on his design for a talking telegraph in 1849 and filed a caveat for his design in 1871 but was unable to finance commercial development. In 2002, the United States House of Representatives passed a resolution recognizing his accomplishment to telecommunications (Library of Congress, 2007).
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Hardy, Lawrence Harold. "A History of Computer Networking Technology." In Networking and Telecommunications, 26–32. IGI Global, 2010. http://dx.doi.org/10.4018/978-1-60566-986-1.ch003.
Full textAbstract:
The computer has influenced the very fabric of modern society. As a stand-alone machine, it has proven itself a practical and highly efficient tool for education, commerce, science, and medicine. When attached to a network—the Internet for example—it becomes the nexus of opportunity, transforming our lives in ways that are both problematic and astonishing. Computer networks are the source for vast amounts of knowledge, which can predict the weather, identify organ donors and recipients, or analyze the complexity of the human genome (Shindler, 2002). The linking of ideas across an information highway satisfies a primordial hunger humans have to belong and to communicate. Early civilizations, to satisfy this desire, created information highways of carrier pigeons (Palmer, 2006). The history of computer networking begins in the 19th century with the invention of the telegraph, the telephone, and the radiotelegraph. The first communications information highway based on electricity was created with the deployment of the telegraph. The telegraph itself is no more than an electromagnet connected to a battery, connected to a switch, connected to wire (Derfler & Freed, 2002). The telegraph operates very straightforwardly. To send a message (electric current), the telegrapher rapidly opens and closes the telegraph switch. The receiving telegraph uses the electric current to create a magnetic field, which causes an observable mechanical event (Calvert, 2004). The first commercial telegraph was patented in Great Britain by Charles Wheatstone and William Cooke in 1837 (The Institution of Engineering and Technology, 2007). The Cooke-Wheatstone Telegraph required six wires and five magnetic needles. Messages were created when combinations of the needles were deflected left or right to indicate letters (Derfler & Freed, 2002). Almost simultaneous to the Cooke-Wheatstone Telegraph was the Samuel F. B. Morse Telegraph in the United States in 1837 (Calvert, 2004). In comparison, the Morse Telegraph was decidedly different from its European counterpart. First, it was much simpler than the Cooke-Wheatstone Telegraph: to transmit messages, it used one wire instead of six. Second, it used a code and a sounder to send and receive messages instead of deflected needles (Derfler & Freed, 2002). The simplicity of the Morse Telegraph made it the worldwide standard. The next major change in telegraphy occurred because of the efforts of French inventor Emile Baudot. Baudot’s first innovation replaced the telegrapher’s key with a typewriter like keyboard. His second innovation replaced the dots and dashes of Morse code with a five-unit or five-bit code—similar to American standard code for information interchange (ASCII) or extended binary coded decimal interchange code (EBCDIC)—he developed. Unlike Morse code, which relied upon a series of dots and dashes, each letter in the Baudot code contained a combination of five electrical pulses. Eventually all major telegraph companies converted to Baudot code, which eliminated the need for a skilled Morse code telegrapher (Derfler & Freed, 2002). Finally, Baudot, in 1894, invented a distributor which allowed his printing telegraph to multiplex its signals; as many as eight machines could send simultaneous messages over one telegraph circuit (Britannica Concise Encyclopedia , 2006). The Baudot printing telegraph paved the way for the Teletype and Telex (Derfler & Freed, 2002). The second forerunner of modern computer networking was the telephone. It was a significant advancement over the telegraph for it personalized telecommunications, bringing the voices and emotions of the sender to the receiver. Unlike its predecessor the telegraph, telephone networks created virtual circuit to connect telephones to one another (Shindler, 2002). Legend credits Alexander Graham Bell as the inventor of the telephone in 1876. He was not. Bell was the first to patent the telephone. Historians credit Italian- American scientist Antonio Meucci as the inventor of the telephone. Meucci began working on his design for a talking telegraph in 1849 and filed a caveat for his design in 1871 but was unable to finance commercial development. In 2002, the United States House of Representatives passed a resolution recognizing his accomplishment to telecommunications (Library of Congress, 2007).
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Chen, Yu-Luen, Walter Chang, and Te-Son Kuo. "Sensors in Assistive Technology." In Handbook of Research on Personal Autonomy Technologies and Disability Informatics, 224–32. IGI Global, 2011. http://dx.doi.org/10.4018/978-1-60566-206-0.ch014.
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This chapter reports on the development of an eyeglass-type infrared-controlled computer interface for the disabled. This system may serve to assist those who suffer from spinal cord injuries or other handicaps to operate a computer. This system is comprised of three major components: (A) an infrared transmitting module; (B) an infrared receiving / signal-processing module; and (C) a main controller, the Intel-8951 microprocessor. The infrared transmitting module utilizes tongue-touch circuitry which is converted to an infrared beam and a low power laser (<0.1mW) beam. The infrared receiving / signal-processing module, receives the infrared beam and fine tunes the unstable infrared beam into standard pulses which are used as control signals. The main controller is responsible for detecting the input signals from the infrared receiving / signal-processing module and verifying these signals with the mapping table in its memory. After the signal is verified, it is released to control the keys of the computer keyboard and mouse interface. This design concept was mainly based on the idea that the use of an infrared remote module fastened to the eyeglasses could allow the convenient control of the input motion on the keys of a computer keyboard and mouse which are all modified with infrared receiving / signal-processing modules. The system is designed for individuals with spinal cord injuries and disabled in which the subjects’ movement are severely restricted. The infrared transmitting module can be easily mounted on eyeglasses or artificial limbs.
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Minear, Roger A., and Mark A. Nanny. "Solution and Condensed Phase Characterization." In Nuclear Magnetic Resonance Spectroscopy in Environment Chemistry. Oxford University Press, 1997. http://dx.doi.org/10.1093/oso/9780195097511.003.0012.
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Improvements in nuclear magnetic resonance (NMR) instrumentation, magnetic field strength, pulse sequences, and computer technology and software have increased the range of applications and specific elements available for study by NMR. The five chapters in this Part clearly indicate the benefits of these advances, especially regarding studies of aquatic, environmental significance. Each of the studies focuses on environmentally significant issues. For example, chlorination is widely used to disinfect drinking waters, a method that can produce undesirable disinfection by-products. This was first recognized in 1974 with the discovery of trihalomethanes in most finished drinking waters where hypochlorite was used for disinfection. Chapter 7 examines the chlorination of alanine and relates it to the chlorination reactions of acetaldehyde and ammonia, a topic of importance with respect to drinking water disinfection. Aluminum is also widely used in drinking water treatment, and understanding its hydrolysis chemistry and complexation behavior is of great importance to aquatic chemistry. In addition, the aquatic chemistry of aluminum is important because acid rain can release soluble aluminum ions from clay into soil water, possibly damaging terrestrial plant life. Aluminum may eventually reach and accumulate in hydrological systems where it can be toxic to aquatic life. Chapters 8 and 9 focus on 27Al NMR in defining aqueous aluminum speciation in a mildly acidic solution or in the presence of complexing organic compounds. Furthermore, aluminum is of environmental and geochemical significance since it is an integral component of clays, another ubiquitous constituent of natural waters (surface and ground). Interaction between clays, cations, and internal water molecules can be significant in understanding the fate and transport of chemicals through the environment. Since colloidal suspensions of clay materials frequently represent challenges to water and wastewater treatment, understanding of physical and chemical processes are of tantamount importance to the environmental scientist and engineer. Chapter 10 explores cation behavior in clay matrices by using “uncommon” nuclei such as 7Li, 23Na, and 133Cs as probes. This is unique in that many NMR studies of complexation in clay have focused primarily upon the nuclei 27A1 and 29Si.
Conference papers on the topic "PULSE (Computer file)"
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Loucks, Richard B. "Evaluation of Thermal Radiation Simulator Rectangular Pulse Characterization Methods." In ASME 1991 International Computers in Engineering Conference and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/cie1991-0104.
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Abstract The thermal output of an aluminum powder/liquid oxygen Thermal Radiation Simulator (TRS) is approximated to that of a rectangular pulse. The output varies as a function of time. The rise and fall times are not relatively abrupt. The problem is how to quantify the thermal output of the TRS into terms of a rectangular pulse. Within the nuclear weapons effects community, flux, or the transient intensity of thermal radiation energy onto a surface, and fluence, the total energy irradiated onto a surface over a given time, are the determining parameters for specifying or evaluating an article’s survivability in the thermal environment. Four methods are used to determine the TRS output for these two parameters, assuming the output to be a perfect rectangular pulse. It was essential to determine which of the four methods best quantified the thermal output average flux and fluence. The four methods were compared by a computational experiment run on a personal computer. The experiment was a simulation of five actual TRS traces irradiated onto a fictitious aluminum plate. The temperature profile of the front surface was computed using a finite difference method calculation. The traces were evaluated using the four characterization methods, generating twenty ideal thermal pulses. The temperature profile of the plate was computed using the twenty ideal thermal pulses. The resulting profiles were compared to profiles generated by the actual data to determine which of the characterization methods best evaluated the TRS output.
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Marion, M. Susan, Maury L. Hull, and Anthony S. Wexler. "Predicting the Effect of Pulse Duration on Fatigue During Electrical Stimulation." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40865.
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Pulse characteristics should be considered when predicting the optimal stimulation strategy to minimize fatigue during Functional Electrical Stimulation. Our previous mathematical model of non-isometric muscle fatigue accounted for the effect of applied load, but not the effect of pulse duration. Therefore, our objectives were to: 1) further develop our model of non-isometric fatigue and 2) experimentally validate the model. A computer-controlled stimulator sent electrical pulses to surface electrodes on the thighs of 25 able-bodied human subjects. Isometric and non-isometric non-fatiguing and fatiguing leg extension ankle forces and/or knee angles were measured. The independent variable was pulse duration (170, 200, 250, 400, and 600 μs) and the dependent variables were angular excursion, velocity, and train duration. The model was fit to measurements from 13 subjects. The equation for one fatigue model parameter was modified. Two other fatigue model parameters were unnecessary and removed. The modified parameter is a function of other parameters within the model. To validate the model, we predicted fatigue at two other pulse durations using the same subjects, at all five pulse durations in a set of new subjects, and at one pulse duration but different applied loads in ten subjects from a previous study. More than 65% of the variability in the measurements was explained by the new force-fatigue model.
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Ou, Shichuan, and Richard B. Rivir. "Shaped-Hole Film Cooling With Pulsed Secondary Flow." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90272.
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The effects of the coolant jet pulsing frequency (PF), duty cycle (DC), and hole shape geometry on heat transfer coefficient and film effectiveness were investigated with a film hole located on a semicircular leading edge test model with an afterbody. Cylindrical and diffusion-shaped holes located at 21.5° from the stagnation line were investigated. An infrared thermography technique with a single transient test was used to determine both the heat transfer coefficient and film effectiveness. Spanwise averaged heat transfer coefficient and film effectiveness were computed from the local values for all test conditions under the same Reynolds number (Re) of 60,000 and density ratio (DR) of 1.11. A dimensionless Frossling number (Fr) was used to represent the heat transfer coefficient. The effects of duty cycles of 50%, 75%, and 100% (continuous coolant) on film effectiveness and heat transfer coefficient were investigated at coolant jet pulsing frequencies of 5 Hertz (Hz) and 10 Hertz. The duty cycle and pulsing frequency were controlled by the opening and closing time settings of two synchronized pulsed valves. The blowing parameters investigated included continuous coolant at the blowing ratios (M) of 0.75, 1.00, 1.50 and 2.00. The subsequent pulsed cases for a combination of pulsing frequency and duty cycle were varied from the corresponding continuous case without changing the coolant flow rate (or blowing ratio) setting for a total of 40 cases for the shaped and cylindrical film holes. The shaped hole provides higher local film effectiveness values than the classical cylindrical hole when coolant flow is steady at M = 1.00. The higher local film effectiveness for the shaped hole was also observed for pulsed cases at M = 1.50 (Meff = 1.25) and M = 2.00 (Meff = 1.07) due to wider film spreading or coverage. The pulsed coolant cases provide higher spanwise averaged film effectiveness than the continuous coolant at M = 1.50 for both hole geometries. In contrast to the film effectiveness, the spanwise averaged Frossling numbers of pulsed coolant are lower compared to the continuous coolant for both hole shapes at the same blowing ratio. Combining the effects of heat transfer coefficient and film effectiveness, one can compute a relative heat load ratio to evaluate the performance of the film cooling. The pulsed coolant cases in general perform better than continuous coolant. The shaped hole geometry provides better film cooling performance than the cylindrical hole geometry for all blowing ratios including the continuous and the pulsed coolant cases studied.
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Lutey, Adrian H. A., Alessandro Fortunato, Simone Carmignato, Filippo Zanini, and Alessandro Ascari. "Laser Profiling of Aluminum Oxide Grinding Wheels." In ASME 2015 International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/msec2015-9293.
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Laser profiling experiments are performed at normal incidence on fine grain medium density aluminum oxide grinding wheels with a pulsed nanosecond 1064nm fiber laser source with maximum pulse fluence 369J/cm2. In order to determine the incision depth and ideal laser pass separation distance, laser exposures are first performed on high purity, low porosity aluminum oxide blocks and subsequently analyzed with an optical profiler operating in confocal mode. This ablation data is then applied to path planning for grinding wheel profiling experiments, with division of the necessary removal depth according to the measured incision depth and ideal pass separation distance. X-ray computed tomography is utilized to determine the resulting profile accuracy as a function of process parameters. Test results indicate a maximum profile accuracy in the order of 200μm; however, in order to approach the accuracy of diamond dressing, some two orders of magnitude lower, it is likely that tangential laser incidence is necessary.
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Bag, Swarup, and M. Ruhul Amin. "Simulation Based Study on Ultra-Short Pulse Laser Welding of Dissimilar Materials Expending Phase Lag Influence." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70068.
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In this work, the thermal simulation of dissimilar fusion welding system is demonstrated by considering the phase lag effects in ultra-short pulse laser source. When the pulse duration is comparable with the electron relaxation time, the hyperbolic effect cannot be neglected in heat transfer analysis due to femtosecond laser. The non-Fourier effect is considered for heat transfer analysis assuming finite delay in development of temperature within the body. This delay is represented in terms of relaxation times connected to heat flux and temperature gradient. In the present work, the simulation has been proposed by developing 3D finite element based heat transfer model using dual phase lag effect. Since the experimental basis of transient temperature distribution in ultra-short pulse laser is extremely difficult or nearly impossible, the model results have been validated with literature reported results. The model has been used further for the simulation of temperature distribution in femtosecond fiber laser welding of dissimilar aluminum alloy and stainless steel. The results in terms of computed isotherm are compared with experimentally evaluated weld pool geometry for dissimilar materials from independent literature. The influence of other characteristic parameters like pulse frequency, pulse width and relaxation times are assessed for this simulation based study which will effectively reduce the costly experimental effort for differential influence of process parameters. A clear guideline of geometric shape and size of weld pool geometry and peak temperature of the welding system with reference to predictable laser parameters are the effective output of this simulation based study. It was observed that the peak temperature reached in a very short interval of time, in the order of nano-seconds. Such high heating or cooling rate impacts on the microstructural changes of the welded joint. In order to reach certain temperature, multiple pulses are required in the material processing of either very thin film or microwelding to keep the thermal shock distortion as low as possible.
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Bag, Swarup, and M. Ruhul Amin. "Thermal Stress Associated With Non-Fourier Heat Conduction in Femtosecond Laser Heating of Multilayer Metallic Films." In ASME 2018 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/imece2018-86144.
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In the present work, the deformation behavior in metallic film subjected to ultra-short laser heating is investigated. Static thermo-elastic behavior is predicted for 100 nm thin film of either single layer or multiple layers. The temperature distribution is estimated from dual-phase lag non-Fourier heat conduction model. The maximum temperature after single pulse is achieved 730 K. The temperature profile for this pulse laser is used to compute elastic stress and distortion field following the minimization of potential energy of the system. In the present work, the simulation has been proposed by developing 3D finite element based coupled thermo-elastic model using dual phase lag effect. The experimental basis of transient temperature distribution in ultra-short pulse laser is extremely difficult or nearly impossible, the model results have been validated with literature reported thermal results. Since the temperature distribution due to pulse laser source varies with time, the stress analysis is performed in incremental mode. Hence, a sequentially coupled thermo-mechanical model is developed that is synchronized between thermal and mechanical analysis in each time steps of transient problem. The maximum equivalent stress is achieved 0.3 GPa. Numerical results show that the predicted thermal stress may exceeds the tensile strength of the material and may lead to crack or damage the thin film.
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Chengyu, Li, Yang Xiaolong, Han Zhuangzhi, and Li Zhiqiang. "Performance Evaluation of Fire-Control Radar with Adaptive Pulse Interval." In 2012 International Conference on Computer Science and Electronics Engineering (ICCSEE). IEEE, 2012. http://dx.doi.org/10.1109/iccsee.2012.292.
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Ji, Pengfei, Yiming Rong, Yuwen Zhang, and Yong Tang. "Molecular Dynamics Investigation of Phase Change Induced by Ultrafast Laser Irradiation." In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-70143.
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Irradiated by ultrafast laser pulse, the phase change phenomena in aluminum film are investigated via molecular dynamics simulation. The embedded-atom method potential is employed to describe atomic interactions. The laser heating is modeled by adding a kinetic energy term to the laser pulse irradiated atom at each time step. The resolidification is realized by thermal conduction to cool down locally melted atoms. The temporal and spatial distribution of atomic motion is recorded to compute the temperature evolution and structure change during melting and resolidification processes. The interface between solid and liquid is identified via Ackland analysis. Due to the temperature difference, diffraction profile of the resolidified aluminum is found different from the aluminum before laser irradiation. The simulation results provide helpful information on the atomic scale temperature variation and structure transformation underlying ultrafast laser induced phase change.
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Mundla, V., J. R. Kadambi, S. Sastry, C. Deng, and Y. Zhou. "Measurement of Liquid Layer Thickness Using Ultrasound Technique." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80022.
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The use of ultrasound technique to obtain the liquid film thickness was investigated. Ultrasound imaging is a technique that uses high frequency sound waves to produce precise images of structures. Ultrasound imaging is based on the same principle as SONAR (Sound Navigation and Ranging) during which a transducer capable of generating and receiving high frequency sound waves, sends pulses of sound waves into the interrogation area and the sound reflected back (echo) form any interface (such as water air interface) within the interrogation plane is obtained by the transducer. The time taken for the sound wave to travel from the transducer surface to the water air interface is obtained from the delay of the echo signal with regard to the transmitted signal; this time is used to compute the distance of the interface knowing the velocity of sound in medium. An experiment was set up to measure the depth of water in a container using ultrasound technique. A-mode (amplitude-mode) scanning was used where a pulsed ultrasound wave is directed into the interrogation region and echoes generated at various interfaces are detected. It is observed that levels as low as 0.55 mm were measured.
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Wang, Liusheng, Pavel Fomitchov, and Sridhar Krishnaswamy. "Vibration Measurement Using Additive Speckle Interferometry." In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0718.
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Abstract A method for obtaining structural vibration amplitudes quantitatively is proposed based on the stroboscopic speckle interferometer. The technique requires five frames of additive speckle patterns: the first one (S0) taken with the laser illumination pulsed at instants when the vibration achieves its two zero amplitude positions within one sinusoidal vibration cycle of the specimen; and the remaining four (S1 through S4) taken with the illumination pulses arranged at times when the vibration is at its maximum and minimum amplitudes. During the acquisition of speckle patterns S1 through S4, the phase of the reference beam is appropriately shifted between the two pulses within each vibration cycle. The last four speckle patterns are then subtracted from the first one to yield four correlation fringe patterns with relative phase shifts of 0, π/2, π and 3π/2 respectively. These fringe patterns are then utilized to derive a phase map using a four-step phase calculation algorithm and finally the vibration amplitude and the sign of the vibrational nodes can be readily obtained from the phase map quantitatively. Results have been obtained using a speckle shearographic setup for the vibration measurement of a flat bottom-holed aluminum specimen vibrating at different frequencies.