36,799 research outputs found

    Reducing contact resistance at semiconductor to metal or aluminum to metal interfaces

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    Etchant containing chloroplatinous or chloroplatinic acid greatly reduces contact resistance between metallic surfaces. Etching results in a monolayer plating of platinum on the wafer surface, preventing oxide growth

    The Steady-State Transport of Oxygen through Hemoglobin Solutions

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    The steady-state transport of oxygen through hemoglobin solutions was studied to identify the mechanism of the diffusion augmentation observed at low oxygen tensions. A novel technique employing a platinum-silver oxygen electrode was developed to measure the effective diffusion coefficient of oxygen in steady-state transport. The measurements were made over a wider range of hemoglobin and oxygen concentrations than previously reported. Values of the Brownian motion diffusion coefficient of oxygen in hemoglobin solution were obtained as well as measurements of facilitated transport at low oxygen tensions. Transport rates up to ten times greater than ordinary diffusion rates were found. Predictions of oxygen flux were made assuming that the oxyhemoglobin transport coefficient was equal to the Brownian motion diffusivity which was measured in a separate set of experiments. The close correlation between prediction and experiment indicates that the diffusion of oxyhemoglobin is the mechanism by which steady-state oxygen transport is facilitated

    Diffusivity Measurements of Human Methemoglobin

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    Experimental measurements of the diffusion coefficient of human methemoglobin were made at 25°C with a modified Stokes diaphragm diffusion cell. A Millipore filter was used in place of the ordinary fritted disc to facilitate rapid achievement of steady state in the diaphragm. Methemoglobin concentrations varied from approximately 5 g/100 ml to 30 g/100 ml. The diffusion coefficient in this range decreased from 7.5 x 10^(-7) cm^2/sec to 1.6 x 10^(-7) cm^2/sec

    Complementary-MOS binary counter with parallel-set inputs

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    Metal oxide semiconductor four-stage binary counter contains reset capability as well as four parallel-set inputs gated in by a logic signal. Parallel-set inputs permit setting the counter into any of sixteen possible states

    Design and development of a digital subsystem employing n and p-channel Mos Fet's in complementary circuits in an integrated circuit array Final report, 1 May 1967 - 30 Apr. 1968

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    Digital subsystem design and development employing n-channel and p-channel in MOS FET units in complimentary circuits in integrated circuit arra

    Assessing the Effectiveness of a Computer Simulation in Introductory Undergraduate Environments

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    We present studies documenting the effectiveness of using a computer simulation, specifically the Circuit Construction Kit (CCK) developed as part of the Physics Education Technology Project (PhET) [1, 2], in two environments: an interactive college lecture and an inquiry-based laboratory. In the first study conducted in lecture, we compared students viewing CCK to viewing a traditional demonstration during Peer Instruction [3]. Students viewing CCK had a 47% larger relative gain (11% absolute gain) on measures of conceptual understanding compared to traditional demonstrations. These results led us to study the impact of the simulation's explicit representation for visualizing current flow in a laboratory environment, where we removed this feature for a subset of students. Students using CCK with or without the explicit visualization of current performed similarly to each other on common exam questions. Although the majority of students in both groups favored the use of CCK over real circuit equipment, the students who used CCK without the explicit current model favored the simulation more than the other grou
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