ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Anisotropic conducting adhesives for electronic assembly (1997)

Whalley, David C. ; Mannan, Samjid H. ; Williams, David J.

Bradford : Emerald

Assembly automation 17 (1997), S. 66-74

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ISSN: 0144-5154

Source: Emerald Fulltext Archive Database 1994-2005

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Presents some experimental and theoretical results from research exploring the design rules and relevant process parameters in the assembly of electronic components using anisotropic conductive adhesive materials. The experimental configurations studies have geometries representative of flip-chip and micro ball grid array chip scale packaging. Evaluates a range of materials combinations, including (random filled) adhesive materials based on both thermoplastic and thermo-setting resin systems, combined with both glass reinforced polymer printed circuit board and silver palladium thick film on ceramic substrate materials. Also presents a summary of assembly experiments which have been conducted using a specially developed instrumented assembly system. This test rig allows the measurement of the process temperatures and pressures and their relationship with the consequent bondline thickness reduction and conductivity development. Finally summarizes the capabilities of models which have been developed of the assembly process and of the final joint properties.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1108/01445159710163481

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2

Electronic Resource

A simplified model of the reflow soldering process (2002)

Whalley, David C. ; Hyslop, Stuart M.

Bradford : Emerald

Soldering & surface mount technology 14 (2002), S. 30-37

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ISSN: 0954-0911

Source: Emerald Fulltext Archive Database 1994-2005

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Previous models of temperature development during the reflow soldering process have typically used commercially available, general purpose, finite difference/finite element modelling tools to create detailed three dimensional representations of both the product and of the reflow furnace. Such models have been shown to achieve a high degree of accuracy in predicting the temperatures a particular PCB design will achieve during the reflow process, but are complex to generate and analysis times are long, even when using modern high performance computer workstations.This paper will report on the development of a simplified model of the process, which uses less complex representations of both the product and the process, together with a simple numerical solver developed specifically for this application, whilst achieving an accuracy comparable with more detailed models. In the simplified model, the product is divided into elements, which are represented using a two-dimensional mesh of thermal conductances linking thermal masses. The values of these conductances and masses are calculated based on the averaged properties of the PCB material and attached components within the area of each of the elements. The representation of the specific reflow furnace is based on measurements of the temperature and level of thermal convection at each point along the length of the furnace, thereby avoiding the necessity of making detailed measurements of the furnace geometry and air flow velocities. The combination of these two simplification techniques allow the reduction of analysis time for a relatively simple PCB from in the order of an hour on a high performance Unix workstation to under a second on a Pentium class PC running Microsoft Windows.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1108/09540910210416440

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3

Electronic Resource

4-Methoxy-2-methyltetrahydropyrans: chiral leukotriene biosynthesis inhibitors, related to ICI D2138, which display enantioselectivity (1993)

Crawley, Graham C. ; Briggs, Malcolm T. ; Dowell, Robert I. ; [et al.]

s.l. : American Chemical Society

Journal of medicinal chemistry 36 (1993), S. 295-296

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ISSN: 1520-4804

Source: ACS Legacy Archives

Topics: Chemistry and Pharmacology

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1021/jm00054a016

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4

Electronic Resource

The application of IR thermography to process monitoring and control of reflow soldering (1998)

Conway, Paul ; Whalley, David ; Wilkinson, Michelle ; [et al.]

Bradford : Emerald

Soldering & surface mount technology 10 (1998), S. 13-18

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ISSN: 0954-0911

Source: Emerald Fulltext Archive Database 1994-2005

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: This paper describes a technique for the monitoring and control of the reflow soldering process. The technique combines state-of-the-art infra-red (IR) sensor technology, coupled with application-specific process monitoring and control software, providing a unique capability both to monitor product temperatures during processing and to modify the process settings. The development of techniques to allow variation of the heat transfer from the oven to the in-process printed circuit assemblies (PCAs) provides the means to adjust the soldering oven's process settings for each individual PCA. This automatic profiling ensures consistent thermal histories and optimises oven energy consumption. Archiving of the reflow profiles along with temperatures recorded for each PCA provides full traceability to the reflow process settings for each individual PCA. The incorporation of IR sensing technology also provides a means to monitor the performance of the process.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1108/09540919810203766

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5

Electronic Resource

Investigation of a solder bumping technique for flip-chip interconnection (2000)

Hutt, David A. ; Rhodes, Daniel G. ; Conway, Paul P. ; [et al.]

Bradford : Emerald

Soldering & surface mount technology 12 (2000), S. 7-14

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ISSN: 0954-0911

Source: Emerald Fulltext Archive Database 1994-2005

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: As the demand for flip-chip products increases, the need for low cost high volume manufacturing processes also increases. Currently solder paste printing is the wafer bumping method of choice for device pitches down to 150-200µm. However, limitations in print quality and stencil manufacture mean that this technology is not likely to move significantly below this pitch and new methods will be required to meet the demands predicted by the technology roadmaps. This paper describes experiments conducted on carriers made from silicon for bumping of die using solder paste. An anisotropic etching process was used to generate pockets in the silicon surface into which solder paste was printed. Die were then placed against the carrier and reflowed to transfer the solder directly to the bondpads. An assessment was carried out of the potential application and limitations of this technique for device pitches at 225 and 127µm.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1108/09540910010312366

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6

Electronic Resource

Supporting Timing Analysis by Automatic Bounding of Loop Iterations (2000)

Healy, Christopher ; Sjödin, Mikael ; Rustagi, Viresh ; [et al.]

Springer

Real-time systems 18 (2000), S. 129-156

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ISSN: 1573-1383

Keywords: hard real-time systems ; worst-case execution time ; static analysis

Source: Springer Online Journal Archives 1860-2000

Topics: Computer Science

Notes: Abstract Static timing analyzers, which are used to analyze real-time systems, need to know the minimum and maximum number of iterations associated with each loop in a real-time program so accurate timing predictions can be obtained. This paper describes three complementary methods to support timing analysis by bounding the number of loop iterations. First, an algorithm is presented that determines the minimum and maximum number of iterations of loops with multiple exits. Even when the number of iterations cannot be exactly determined, it is desirable to know the lower and upper iteration bounds. Second, when the number of iterations is dependent on unknown values of variables, the user is asked to provide bounds for these variables. These bounds are used to determine the minimum and maximum number of iterations. Specifying the values of variables is less error prone than specifying the number of loop iterations directly. Finally, a method is given to tightly predict the execution time of inner loops whose number of iterations is dependent on counter variables of outer level loops. This is accomplished by formulating the total number of iterations of a loop in terms of summations and solving the resulting equation. These three methods have been successfully integrated in an existing timing analyzer that predicts the performance for optimized code on a machine that exploits caching and pipelining. The result is tighter timing analysis predictions and less work for the user.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1008189014032

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7

Electronic Resource

Timing Analysis for Data and Wrap-Around Fill Caches (1999)

White, Randall T. ; Mueller, Frank ; Healy, Chris ; [et al.]

Springer

Real-time systems 17 (1999), S. 209-233

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ISSN: 1573-1383

Keywords: Timing analysis ; data cache ; wrap-around fill cache ; worst-case execution time

Source: Springer Online Journal Archives 1860-2000

Topics: Computer Science

Notes: Abstract The contributions of this paper are twofold. First, an automatic tool-based approach is described to bound worst-case data cache performance. The approach works on fully optimized code, performs the analysis over the entire control flow of a program, detects and exploits both spatial and temporal locality within data references, and produces results typically within a few seconds. Results obtained by running the system on representative programs are presented and indicate that timing analysis of data cache behavior usually results in significantly tighter worst-case performance predictions. Second, a method to deal with realistic cache filling approaches, namely wrap-around-filling for cache misses, is presented as an extension to pipeline analysis. Results indicate that worst-case timing predictions become significantly tighter when wrap-around-fill analysis is performed. Overall, the contribution of this paper is a comprehensive report on methods and results of worst-case timing analysis for data caches and wrap-around caches. The approach taken is unique and provides a considerable step toward realistic worst-case execution time prediction of contemporary architectures and its use in schedulability analysis for hard real-time systems.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1008190423977

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8

Electronic Resource

A retargetable technique for predicting execution time of code segments (1994)

Harmon, Marion G. ; Baker, T. P. ; Whalley, David B.

Springer

Real-time systems 7 (1994), S. 159-182

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ISSN: 1573-1383

Source: Springer Online Journal Archives 1860-2000

Topics: Computer Science

Notes: Abstract Predicting the execution times of straight-line code sequences is a fundamental problem in the design and evaluation of hard real-time systems. The reliability of system-level timings and schedulability analysis rests on the accuracy of execution time predictions for the basic schedulable units of work. Obtaining such predictions for contemporary microprocessors is difficult. This paper presents a new technique called micro-analysis for predicting point-to-point execution times on code segments. It uses machine-description rules, similar to those that have proven useful for code generation and peephole optimization, to translate compiled object code into a sequence of very low-level (micro) instructions. The stream of micro-instructions is then analyzed for timing, via a three-level pattern matching scheme. At this low level, the effect of advanced features such as instruction caching and overlap can be taken into account. This technique is compiler and language-independent, and retargetable. This paper also describes a prototype system in which the micro-analysis technique is integrated with an existing C compiler. This system predicts the bounded execution time of statement ranges or simple (non-nested) C functions at compile time.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01088803

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9

Electronic Resource

The effect of density on the gastric emptying of single- and multiple-unit dosage forms (1986)

Davis, Stanley S. ; Stockwell, Anita F. ; Taylor, Margaret J. ; [et al.]

Springer

Pharmaceutical research 3 (1986), S. 208-213

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ISSN: 1573-904X

Keywords: gastrointestinal transit ; pellet density ; floating formulations, gastric emptying

Source: Springer Online Journal Archives 1860-2000

Topics: Chemistry and Pharmacology

Notes: Abstract The gastric emptying of pellets and single units of different densities has been followed in healthy subjects using the technique of gamma scintigraphy. The gastric emptying of the light pellets was affected by their buoyancy in the upper part of the stomach. However, the mean gastric emptying rates of pellets and single units were not significantly affected by density. Floating or buoyant delivery systems may have little advantage over conventional systems. The presence of food in the stomach was found to be the major factor in determining the gastric emptying of single units.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1016334629169

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