摘要:

The modulation frequency on the cylindrical mirror analyzer of a scanning Auger microscope has been synchronized to the digital scanning system. This technique allows one to obtain an Auger image free from moire´ patterns which arise from the beat between scanning and modulation frequencies, and permits operation at frequency settings which optimize use of the electronics in the detection system.

ISSN:0034-6748    

DOI:10.1063/1.1135666

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A differential dilatometer capable of detecting volume changes of 1 part in 105in specimens exposed to a hydrogen atmosphere at 6.2 MPa and 500°C is described. The swelling of an alloy under hydrogen‐attack conditions can be studied over a wide range of hydrogen pressures and temperatures by use of a single specimen.

ISSN:0034-6748    

DOI:10.1063/1.1135667

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A temperature‐jump apparatus with repetitive microwave heating and spectrophotometric detection is described. Temperature jumps of 1.5°C are achieved in a flow microcell within 1.5 &mgr;s (two shorter heating times of 0.5 and 0.25 &mgr;s are also available) at a repetition rate up to 50 Hz. On‐line accumulation of the relaxation signals is performed with a PDP 11 processor, leading to very short recording times (more than 1000 signals accumulated in less than 50 s) and to a sensitivity better than 10−4optical density (OD) units. Nonlinear identification treatment permits processing the summed signal even when it is strongly blurred by noise. To demonstrate the capabilities of our apparatus, highly shifted fast prototropic equilibria in aqueous solutions of pyrimidine base have been studied.

ISSN:0034-6748    

DOI:10.1063/1.1135668

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The authors describe the development of millimeter‐size photopreionization stabilized atmospheric pressure uv nitrogen lasers. Sealed‐off versions of these lasers can provide peak powers of 30–150 kW and average power of 1–5 mW. The discharge and pulsing concepts are very general and are being adapted to a variety of other high‐pressure TE‐type laser systems.

ISSN:0034-6748    

DOI:10.1063/1.1135669

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Four different operating configurations of a time‐to‐amplitude converter were examined for performance in the time‐correlated single‐photon fluorimetric experiment. Parameters considered were the intensity/count linearity, maximum data rate, and decay distortion. The inverted configuration with an interactive source was optimum. This arrangement combined total linearity with a 37‐kHz conversion rate and did not distort the fluorescence decay. In addition, the pulse‐height analyzer could severely limit the overall system data rate and could destroy the TAC intensity/count linearity.

ISSN:0034-6748    

DOI:10.1063/1.1135671

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The VISAR (velocity interferometer system for any reflector) has become a common tool used in experiments where high surface velocities must be measured. A modification that uses previously wasted interferometer light to more than double output signals and to cancel noise is described. Laser power is used more efficiently, VISAR performance in the presence of intense target self‐light is improved, and only two data signals are required instead of the usual three or four. Effects of changing light intensity and fringe visibility are eliminated using a novel detection system with a simplified solution for velocity.

ISSN:0034-6748    

DOI:10.1063/1.1135672

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

The extremely simple mathematical technique called ’’straightening through smoothing,’’ which is a numerical frequency filter, is generalized in order to provide a transmission function having any shape. This frequency filter requires such a small memory that it can be performed using a minicomputer or even a programmable hand held calculator and the number of channels used is not limited to a power of 2, as in the case of the fast Fourier transform. For some filtering functions the number of operations required is smaller than with the fast Fourier transform.

ISSN:0034-6748    

DOI:10.1063/1.1135673

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A simple metal ion source capable of producing a continuous, uncontaminated, high current beam of Sb ions is presented. It produced a total ion current of 200 &mgr;A at 1 kV extraction voltage. A discharge occurred in the source at a pressure of 6×10−4Torr. The ion current extracted from the source increased with the 3/2 power of the extraction voltage. The perveance of the source and ion density in the plasma were 8×10−9and 1.8×1011cm−3, respectively.

ISSN:0034-6748    

DOI:10.1063/1.1135645

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

Recent advances have been made in the operation of long‐path absorption cells which make them easier to align and improve the accuracy of measurements made with them. Only one person is required now for routine measurements of low absorption coefficients of atmospheric absorbers. Unique gear designs for the adjustment of the cell mirrors are described which utilize low‐torque linear drives and make possible rapid changes in pathlength and precision repositioning of the cell output beam at long pathlengths. Automation of cell operation by the use of remote Selsyn controls is described. Several techniques are discussed for precision optical alignment of long‐path absorption cells, including the use of infrared radiation sources. The system accuracy which results from these refinements in operation is included.

ISSN:0034-6748    

DOI:10.1063/1.1135641

出版商:AIP    

年代:1979

数据来源: AIP

摘要:

A new analysis of the factors affecting the driving head within a capillary viscometer has identified a previously undetected source of error due to surface tension. In contrast to the well‐known capillary rise correction to the effective driving head, this additional effect requires that a correction be made to the apparent head of liquid. Calculations show that this source of error may be responsible for deviations in experimental results as large as 1%. A new calibration equation which compensates for both surface tension effects is recommended.

ISSN:0034-6748    

DOI:10.1063/1.1135642

出版商:AIP    

年代:1979

数据来源: AIP