نتایج جستجو برای: teflon
تعداد نتایج: 1952 فیلتر نتایج به سال:
A universal cell was constructed, which allows measurements of the resistance (d.c.), capacity, optical reflectivity, and spectral absorption of black lipid films simultaneously. These measurements reflect different properties of the films, supplementary to each other. The purpose is to eliminate differences of experimental conditions especially in recombination experiments with proteins. The c...
A teflon chemostat constructed for studies of microbial trace metal metabolism is described. The utility of this continuous culture system was demonstrated with Streptococcus mutans, in which iron and manganese stimulated growth in ranges of 0.18 to 0.45 and 18 to 54 microM, respectively. This device should facilitate studies of the effect of trace metals on a variety of physiological functions.
We found significant differences in mercury fluxes measured with a dynamic surface mercury flux chamber made of Teflon versus one made of polycarbonate. While both materials responded reasonably well when virgin materials were used, the polycarbonate chamber was found to exhibit significant chamber blanks under light after it was exposed to surface mercury fluxes of >100 ng/m2/h. Most significa...
In hydrogen masers, the atomic resonance quality factor is largely determined by the properties of the Teflon coating on the quartz storage bulb. Normally a good Teflon coating will last many years. On the other hand, there may be a relatively fast degradation of the quality factor if the Teflon coating is bad. This paper updates a series of observations and measurements performed on an hydroge...
Excision of giant emphysematous bullae commonly results in a persistent air leak that requires prolonged intercostal drainage and delays recovery. To minimise this we have used Teflon (polytetrafluoroethylene) strips to buttress the suture line and secure pneumostasis. During 1976-84 eight bullae were excised in seven patients. One patient had bilateral staged thoracotomies. All chest drains we...
Patients who have undergone thyroidectomy may have recurrent laryngeal nerve injury; until recently, Teflon injection was commonly used for vocal cord medialization. We present a case of a patient who underwent thyroidectomy who had significantly increased and unilateral (18)F-fluorodeoxyglucose uptake in the neck, which was found to be localized to the left vocal cord by use of combined positr...
A comparison of Teflon slides and the Army Insecticide Measuring System for sampling aerosol clouds.
The effects of method of droplet analysis, reader of Teflon slides and distance on mass median diameter of a Cythion aerosol cloud were examined in the calibration of an Army Insecticide Measuring System (AIMS). There were no significant differences in results among readers and between the AIMS and readers. There were slight but statistically significant differences between readers of Teflon sl...
We present a general inexpensive method for realizing a Teflon stack microreactor with an integrated piezoelectric actuator for conducting chemical synthesis with solid products. The microreactors are demonstrated with palladium-catalyzed C-N cross-coupling reactions, which are prone to clogging microchannels by forming insoluble salts as by-products. Investigations of the ultrasonic waveform a...
The Authors describe a new dynamic endonasal Teflon stent, nick-named "little gun", used after the surgical transnasal endoscopic treatment of bilateral choanal atresia in a 4-day-old male. This Teflon stent, conceived to perfectly fit the new naso-choanal openings and to achieve an "orthopaedic" tutorial function, is made of three portions: "A", the barrel, "B", the breech, "C" the butt. The b...
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