Review of accelerator magnet design in the world

It is pointed out that the construction of large particle accelerators and storage rings requires the design and fabrication of large numbers of bending, focusing, and correction magnets. Normal conducting iron yoke magnets are standard for low fields. Two designs representing efforts for manufacturing cost reduction are discussed. Emphasis is placed on superconducting magnets necessary for high fields. Many details of the well-established cos&thetas; one or two layer coil design using NbTi superconductor are presented. Peculiarities in the use of Nb₃Sn superconducting material are mentioned. Examples of alternative superconducting magnet designs are given. Finally, the performance of HERA (Hadron-Electron Ring Accelerator) magnets produced in quantity by industry is presented     

Finite difference time-domain analysis of planar microwave circuits

Contents The application of finite difference time domain analysis techniques to planar microwave integrated circuit design is discussed. It is shown that using this technique, three-dimensional discontinuity problems in planar microstrip and coplanar circuits can be analyzed in a full-wave approach.

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Finite-Differenzen-Analyse von planaren Mikrowellen-schaltungen im Zeitbereich

Übersicht Es wird die Anwendung der Finiten-Differenzen-Analyse elektromagnetischer Felder im Zeitbereich auf den Entwurf integrierter Mikrowellenschaltungen diskutiert. Es wird gezeigt, daß durch Anwendung dieser Technik eine Lösung der Beschreibungsprobleme für dreidimensionale Schaltkreis-Diskontinuitäten in planarer Mikrostreifenleitungstechnik und in koplanarer Leitungstechnik unter Berücksichtigung der vollen Welleneigenschaften gefunden werden kann. Verschiedene Beispiele von Analysen planarer Mikrowellenbauelemente werden diskutiert und die Ergebnisse mit Messungen verglichen.

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Dedicated to Prof. Dr.-Ing. Herbert Döring on the occasion of his 80th birthday     

Locally advanced primary colorectal cancer: intraoperative electron and external beam irradiation +/- 5-FU

PURPOSE: For locally advanced primary colorectal cancer, our institution has combined intraoperative electron irradiation (IOERT) with external beam irradiation (EBRT) +/- 5-fluorouracil (5-FU) and surgical resection. Disease control and survival were compared with the current IOERT and prior non-IOERT regimens. METHODS AND MATERIALS: From April 1981 through August 1995, 61 patients received an IOERT dose of 10-20 Gy, usually combined with 45-55 Gy of fractionated EBRT; 56 had minimum follow-up of 18 months. The amount of residual disease remaining at IOERT after exploration and maximal resection in the 56 patients was gross in 16, < or = microscopic in 39, and unresected in 1. RESULTS: Survival (SR) and disease control were analyzed as a function of potential prognostic factors. Factors that achieved statistical significance for improved overall survival included treatment sequence of preop EBRT + 5-FU (vs. postoperative EBRT + 5-FU, p = 0.003) and < or = microscopic residual disease after maximal resection (vs. gross residual, p = 0.005). Those that appeared to favorably impact disease-free survival included EBRT + 5-FU (vs. EBRT alone, p = 0.01), < or = microscopic residual (vs. gross, p = 0.0014), and colon site of primary (vs. rectum, p = 0.009). Failures within an irradiation field have occurred in 4 of 16 patients (25%) who presented with gross residual after partial resection vs. 2 of 39 (5%) with < or = microscopic residual after gross total resection (p = 0.01). The significant prognostic factors for a decrease in distant metastases were the same as for disease-free SR with respective p-values of 0.013 (EBRT + 5-FU), 0.008 (microscopic residual), and 0.03 (colon primary). The current data suggests a relationship between IOERT dose and incidence of Grade 2 or 3 neuropathy (< or = 12.5 Gy--1 of 29 or 3%, > or = 15 Gy--6 of 26 or 23%, p = 0.03). CONCLUSIONS: Both overall survival and disease control appear to be improved with the addition of IOERT to standard treatment. More routine use of systemic therapy is indicated as a component of IOERT containing treatment regimens because the incidence of distant metastases was 50% of patients at risk.     

ATMOSPHERIC FREEZE-DRYING PART 2 : MODELLING DRYING KINETICS USING ADSORPTION ISOTHERMS

This paper describes the modelling of atmospheric pressure freeze-drying using a fluidized bed of adsorbent. The original feature of this modelling, based on a model of the “Uniformly Retreating Ice Front” type, is the coupling of the laws of heat and mass transfer as well as the introduction into the model of adsorbent sorption isotherms. The model which describes dehydration kinetics has been validated further to experiments on potatoes. The working parameters of the facility were optimized thanks to the model. This new freeze-drying process may well be useful for small freeze-dried products dried at a temperature close to their melting point.     

From static approximations to full-wave analysis: The analysis of planar line discontinuities

A comparison of different methods for the characterization of planar line discontinuities with emphasis on microstrip discontinuities is given, thereby describing the present state of the art in this area of microwave circuit CAD. Quasi-static equivalent circuit models, the magnetic wall waveguide model of microstrip discontinuities, full-wave analysis techniques like the orthogonal series expansion and mode matching techniques, the spectral domain analysis technique using roof-top functions, and the finite-difference time-domain technique are described briefly and compared with respect to their numerical efficiency and their capabilities.