Engelbert Ziegler

Anwendung von Auto- und Cross-Korrelationsverfahren zur Auswertung von experimentellen ESR-Hyperfeinstrukturen

The use of computer-calculated spectra for the verification of tentative assignments in ESR spectra is well established. Auto- and cross-correlation methods provide a simpler and more exact method for the evaluation of hyperfine structures of ESR signals. The advantages and limitations of these methods are illustrated by a series of experimental examples.ZusammenfassungNeben der lange benutzten Technik, die Zuordnung von ESR-Spektren mit Hilfe von (Computer-)berechneten Spektren zu kontrollieren, können Auto- und Cross-Korrelationsverfahren zu einer rationelleren und genaueren Auswertung der Hyperfeinstrukturen von ESR-Signalen eingesetzt werden. An einer Reihe von experimentellen Beispielen werden die Möglichkeiten und Grenzen dieser Methoden zur Bestimmung von Kopplungskonstanten diskutiert.

Colachrom, a command language for chromatographic data processing

Abstract A command language for the interactive computer processing of chromatograms is described. Report data files, resulting from a peak evaluation program, are processed with single-line commands. Reference peaks for quantitative evaluation or for retention index calculations can be specified, compound names or response factors be assigned, etc. Customer-specific reports can be generated. Several commands operate on the unreduced digitized chromatograms, e.g., repeat peak evaluation with modified peak search parameters or with a user-corrected baseline. Commands can be combined into procedures for semi-automatic processing of series of chromatograms. Various forms of interactive graphical presentations supplement the command language.

A centralized, hierarchically structured computer system for chemical research and analytical instrumentation☆

Abstract An hierarchically structured, centralized compute system, replacing an obsolete central DECsystem-10, can be used for all the computational tasks in chemical research, as well as for real-time data acquisition and evaluation for numerous analytical instruments, required in a large Institute. In this hierarchical system, the real-time tasks are done by local minicomputer satellites that are tailored to special requirements in the laboratories. All higher level data processing and data storage demands are covered by the central system, consisting of two VAX11/780 computers, to which all satellites as well as all user terminals are connected. The design criteria are described as well as some of the software packages developed for this system.

A computer system for measuring fast-scan lowresolution mass spectra

A microprocessor-based satellite computer system (MASDAT) controls a low-resolution, fast-scan mass spectrometer for the measurement of series of spectra. Special digitization hardware (logarithmic A/D converter) and software algorithms are necessary to achieve a dynamic range (ratio of highest to lowest intensity) of about 105 in peak heights. Up to three MASDAT satellites can be connected to a host computer. Synchronized parallel programs in the host system communicate with the operator, calibrate the mass scale, print an interscan report, and store final spectra and, optionally, unreduced data on mass storage devices. Host software is described for a RSX11M and for a VAX/VMS operating system.

Laboratory computer systems and the role of the human interface

Abstract The importance of the “human interface” between the operator and a laboratory computer system is emphasized. Some rules for communication through dialogue programs and command languages as well as for the presentation of computer output are given. The degree of automation of the evaluation of analytical data versus interactive treatment is discussed.

Interactive processing of chromatograms with display terminals

SummaryThe use of display terminals for the interactive processing of gas chromatographic data in the Mülheim Computer System is described and discussed.The stepwise and flexible evaluation of chromatograms as they are especially met in research and development laboratories is facilitated considerably.1.The correlation of analogue and digital presentations of chromatographic results can easily be performed by the operator at the display screen via peak numbers or retention parameters.2.Chromatograms can be investigated in more detail by fast plotting of any desired section of the total chromatogram in any desired scales of coordinates.3.The fit of software constructed baselines to the chromatograms can be studied, baseline and solvent peak subtraction methods can be performed easily.

The application of colachrom, a new command language for chromatographic data processing

Abstract The COLACHROM command language is tailored to the needs of interactive processing of chromatographic data. Single-line commands operate on “raw data” files of unreduced digitized chromatograms as well as on report data files resulting from a previous peak analysis. Examples of the application of this command language are given.

Die Schwingungsspektren von Tetrachloräthylenoxid,cis-undtrans-1,2-Dichloräthylenoxid

Die Schwingungsspektren des Tetrachlorathylenoxids sowie descis-und destrans-1,2-Dichlorathylenoxids wurden untersucht. Eine Zuordnung der beobachteten Frequenzen zu den Normalschwingungen wird vorgeschlagen.

Trennung von Naturstoffen unter Verwendung der Gelpermeationstrennung oder einer Vorsäule, speziell für die Analytik der Kapillar-Gaschromatographie

SummaryGC separation of natural products is upset by nonvolatile compounds. The problems arise from thermal and catalytic cracking in the injector, from ghost peaks and base line drift. A treatment is shown for obtaining an improvement in citrus analysis by using simple gelpermeation chromatography for pre-separation. A second method describes the separation of the high relative molecular mass compounds with a pre-column GC-equipment. A simple conversion is demonstrated for this modification of GC apparatus.ZusammenfassungDie Gaschromatographie von Naturstoffen wird durch nicht-flüchtige Anteile sehr erschwert. Störungen erfolgen durch Krackung und Katalysatorwirkung im Einspritzblock, Geisterpeaks und Grundlinienversatz. Mittels einer einfachen Gelchromatographie-Vortrennung wird eine Verbesserung der Citrusölanalytik beschrieben. Werden die höhermolekularen Stoffe nicht benötigt, kann man diese durch Verwendung einer Vorsäule am Gaschromatographen ausschalten. Ein einfacher Umbau am GC Gerät wird angegeben.

9 PCs and Networking

Publisher Summary The chapter presents a discussion on personal computers (PCs) and networking. Networking of PCs, and of computers in general, allows for the exchange of information between the networked computers, the nodes. Data can be collected and assembled into commonly accessible data banks. Special peripherals, like high-performance printers, but also specialized processing hardware, for example, for FFT-applications, can be shared by many users. In short, the integration of PCs in networks, if efficiently implemented, combines the strengths of a centralized system with the advantages of personal computing. Within Wide-Area Networks (WAN) computers are connected over long distances via public telecommunication lines provided by national FITS. WANs are especially useful to access host computers with large databases, example, for the retrieval of bibliographic information. Another use of WANs are internationally operated electronic mail systems. Currently, possible transfer media in LANs: simple twisted-pair wires, coaxial cable, and fiber optic cables, are characterized and presented in the chapter. Initially the Ethernet specifications had been promoted by the companies Xerox, Digital Equipment and Intel. They are based on a bus topology with passive coaxial cables and baseband data transmission. A user of a PC can have access to network resources in different ways, depending on the type of hardware connection used and on the way the PC is operated.