摘要:

A low density plasma source has been constructed utilizing thermally ionized cesium seeded into an argon gas stream. The essential component of this system is the heat exchanger which uses graphite as the primary element of construction. A resistance‐heated helical element and adiabatic stagnation chamber result in a compact arrangement. Some preliminary measurements of the plasma ion density and electron temperature are reported.

ISSN:0034-6748    

DOI:10.1063/1.1719330

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A simple manually operated apparatus for the collection and purification of radon is described. This apparatus employs a heated platinum filament to continuously recombine the radiolytically produced electrolytic gas. The water vapor is condensed into the radium flask obviating the replenishment of water in the radium solution. The radon does not pass through any stopcocks. The apparatus described has given ten years of trouble free service.

ISSN:0034-6748    

DOI:10.1063/1.1719331

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A stopped‐flow fast reaction apparatus is described which permits chemical reactions with rate constants of 50 sec−1, or less, to be followed both spectrophotometrically and calorimetrically. The thermal detector is a single copper‐constantan thermocouple, 5&mgr; thick, with a response time of 3 msec. Using a bandpass of 0 to 80 cps, the signal‐to‐noise ratio is 1:1 for a heat change of 100 &mgr;cal/ml. The apparatus is housed in a 30×30‐cm aluminum cylinder which is temperature stable to ±0.00001°C; reactants can be brought to within 0.001°C of equilibrium in less than 1 h. Acrylic light pipes are employed in the optical detection system to conduct a monochromatic light beam to the observation tube and to conduct the transmitted light to a photomultiplier. Solenoid valves control the mixer inputs; a third solenoid valve stops the flow in 2 msec. The thermal system and calorimeter were analyzed mathematically and two computer programs developed which make corrections for the response time of the system, correct the data for heat diffusion from the observation tube during the reaction, and calculate the first‐order rate constant. The dehydration of carbonic acid was used as a test reaction. Experiments run at 3.8, 18, 24.1, and 36.9°C, using 0.04 molar NaHCO3and 0.02MHCl gave results thermally of 3.12, 15.8, 22.7, 49 sec−1and optically of 3.15, 15.1, 20.6, for the rate constant and 2100, 1413, 970, and 460 cal/mole for &Dgr;H.

ISSN:0034-6748    

DOI:10.1063/1.1719332

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

Using the method of the Laplace transform, corrections for a thermal detection system consisting of a thermocouple, galvanometer, light beam detector, amplifier, and recorder are worked out for a step function and exponential input function. Knowing the system response the rate constant of the exponential can be solved.FortranII programs for the IBM 1620 computer were written and are available on request. The results show that such corrections make it possible to use a detection system only three times as fast as the event for visual corrections to 10% and further that this can be reduced to only a 1% error if the data are taken and analyzed by machine. In addition, the method provides a very rapid method of determining system parameter changes on recorded data and could thus furnish a convenient systems operation monitor.

ISSN:0034-6748    

DOI:10.1063/1.1719334

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A method of analysis by use of the computer has been developed which permits the physical laws governing conduction, or diffusion, to be expressed in first‐order finite form. Solutions are obtained in the one‐dimensional case for rectangular, cylindrical, and spherical geometries without the use of transcendental functions or other conventional mathematical iterative methods. The case of the cylindrical calorimeter with concentric insulating and conducting layers of varying chemical properties and with distributive heat sources arising from biochemical reactions at the center is treated in the transient and steady‐state case.

ISSN:0034-6748    

DOI:10.1063/1.1719335

出版商:AIP    

年代:1965

数据来源: AIP

摘要:

A solid‐state voltage regulator was developed to supply 12 V at up to 5 A to a fixed load (two tungsten lamps) of approximately 4 &OHgr;. The circuit employs a high gain operational amplifier in the feedback loop and the reference potential is supplied by a temperature‐compensated Zener diode in an impedance cancelling bridge. The complete system has a line regulation of 4.5×10−4% for line variations from 100 to 130 V. The dc output impedance for the regulator is 0.003 &OHgr; and the ripple is less than 5&mgr;V peak‐to‐peak at full load. Transient recovery is 120 &mgr;sec no load to full load.

ISSN:0034-6748    

DOI:10.1063/1.1719336

出版商:AIP    

年代:1965

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1719337

出版商:AIP    

年代:1965

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1719338

出版商:AIP    

年代:1965

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1719339

出版商:AIP    

年代:1965

数据来源: AIP

ISSN:0034-6748    

DOI:10.1063/1.1719341

出版商:AIP    

年代:1965

数据来源: AIP