摘要:

A versatile potentiostat which can supply a maximum of 125 ma is described. The potentiostat uses readily available electronic components and an interface is detailed which allows the potentiostat optional computer control.

ISSN:1073-9149    

DOI:10.1080/10739148908543706

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

The performance of a commercially available 1-dimensional x-ray detector based on a directly bombarded self-scanned photo-diode array has been evaluated for x-rays in the 6-8 KeV range. The detector consists of a linear array of 1024 pixels, each approximately 25 μm wide by 2000 μm tall. Modifications to allow cooling to -55°C, which is required for long x-ray exposures, are described. The signal yield is 0.63 ADC counts/Fe55x-ray, resulting in a detective quantum efficiency greater than 0.5 for doses over a range of 10 to 104x-rays per pixel per scan when operated at -55°C. The resolution is about 3 pixels (75 μm FWHM) and the response with respect to dose is linear up to 1.5 x 104x-rays integrated per pixel per scan. There is some non-linearity at doses below about 1000 x-rays/pixel/scan. The detector has very little geometric distortion. The uncorrected uniformity of response of the individual pixels (field flatness) is good to about 2%. However, the variation in responsiveness is stable and a field flatness calibration can be readily used to correct the uniformity of response.

ISSN:1073-9149    

DOI:10.1080/10739148908543707

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Modulated operation of the recently described method of laser diode intracavity absorption spectrometry is discussed. A simple driver circuit which can be used for cw or modulated operation of laser diodes is described. Development of a modulated near infrared laser diode intracavity spectrophotometer for absorption measurements is also provided. This modulated operation mode was compared to cw mode as to sensitivity, noise, ease of operation and detection limit. This modulated driver was implemented using an inexpensive 3 mW 750 nm laser diode and an IR3C02A driver circuit. Advantages of modulated laser diodes in spectroscopic applications are also presented.

ISSN:1073-9149    

DOI:10.1080/10739148908543708

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

Electrical parameters in a drift tube for ion mobility spectrometry (IMS) were evaluated and optimized in resolution and signal intensity for a mixture of three aromatic hydrocarbons. Electric fields which influenced ion currents and peak shapes most were those between the aperture grid and detector plate and between neighboring wires in the ion shutter where optimum electric fields were 3000 and 300 V/cm, respectively. Electric fields on other drift tube components exhibited minor influences on IMS performance suggesting that electrical parameters do not need to be rigidly established throughout most regions of an IMS drift tube. Ion behavior in the IMS drift tube was consistent with models of potential contours for a conducting plane with circular hole.

ISSN:1073-9149    

DOI:10.1080/10739148908543709

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

This paper discusses optimization of the primary beam and the ion extraction optics of a secondary ion mass spectrometer used primarily for organic compound analysis and the imaging analysis of planar chromatograms. A commercial secondary ion electrostatic energy analyzer and accompanying transport optics were redesigned to enhance the extraction of ions sputtered from the chromatographic surface and to increase the ion signal intensities, especially at higher masses. Modifications to a thermionic ion gun and a saddlefield neutral particle gun produced smaller particle beam diameters with maximum particle flux.

ISSN:1073-9149    

DOI:10.1080/10739148908543710

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

摘要:

A researcher in the Anatomy and Cell Biology Division of our institution, the State University of New York Health Science Center at Brooklyn, was conducting cell growth experiments. These experiments required a regular supply of 1-1/2 inch outer diameter petrie dishes, with a 5/16 inch hole drilled precisely in the center of each dish, to allow cell growth to occur in a concentric ring within the dish. A supply of petrie dishes, and an 8 inch Sears Craftsman drill press, were available to the researcher.

ISSN:1073-9149    

DOI:10.1080/10739148908543711

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148908543712

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor

ISSN:1073-9149    

DOI:10.1080/10739148908543713

出版商:Taylor & Francis Group    

年代:1989

数据来源: Taylor