Architectural issues

Samson, 1985] Samson, P. (1985). Architectural Issues in the Design of the System Concepts Digital Synthesizer. In Strawn, J., editor, Digital Audio Enginnering An Anthology, pages 61-94. William Kaufmann. 

From this comparison it can be concluded that on the device level there are fundamental limits for the miniaturization of hybrid-molecular electronics, which are not only governed by the size of the molecule but also depend on the size that an electromechanical or capacitative grid has to have in order to influence its energy levels. These architectural issues regarding the interfacing of a molecular device to the outside world or the assembly of many devices into larger circuits will have to be addressed to a larger extent in the near future. 

According to the reactions in Scheme 10.8, structural variation for the thiapyrylium salt can be accomplished either by using a different benzaldehyde or a different acetophenone and the design space is almost imlimited. In addition, many synthetic routes are known [258]. Thus far only the photoconductivity of XXIV has been documented. The difficulty of uncovering more photo-conductive thiapyrylium salts may be a molecular architecture issue rather than a synthetic issue. Apparently, the stacking requirement for a photocon-ductive thiapyrylium salt aggregate must be very stringent. 

Only limited HIPing of continuous fiber composites has been done, in part because the available canning techniques using metal or glass for encapsulation are cumbersome. HiPing is also potentially somewhat limited for Such composites because of architectural issues. Thus, if one has high... 

Microprocessor technology permitted these technical issues to be addressed in a cost-effec tive manner. In the mid-1970s, a process control architecture referred to as a distributed control system (DCS) was introduced and almost instantly became a commercial success. A DCS consists of some number of microprocessor-based nodes that are interconnec ted by a digital communications network, often called a data highway. The key features of this architecture are as follows ... 

Radical polymerization is often the preferred mechanism for forming polymers and most commercial polymer materials involve radical chemistry at some stage of their production cycle. From both economic and practical viewpoints, the advantages of radical over other forms of polymerization arc many (Chapter 1). However, one of the often-cited "problems" with radical polymerization is a perceived lack of control over the process the inability to precisely control molecular weight and distribution, limited capacity to make complex architectures and the range of undefined defect structures and other forms of "structure irregularity" that may be present in polymers prepared by this mechanism. Much research has been directed at providing answers for problems of this nature. In this, and in the subsequent chapter, we detail the current status of the efforts to redress these issues. In this chapter, wc focus on how to achieve control by appropriate selection of the reaction conditions in conventional radical polymerization. 

Section II discusses the real wave packet propagation method we have found useful for the description of several three- and four-atom problems. As with many other wave packet or time-dependent quantum mechanical methods, as well as iterative diagonalization procedures for time-independent problems, repeated actions of a Hamiltonian matrix on a vector represent the major computational bottleneck of the method. Section III discusses relevant issues concerning the efficient numerical representation of the wave packet and the action of the Hamiltonian matrix on a vector in four-atom dynamics problems. Similar considerations apply to problems with fewer or more atoms. Problems involving four or more atoms can be computationally very taxing. Modern (parallel) computer architectures can be exploited to reduce the physical time to solution and Section IV discusses some parallel algorithms we have developed. Section V presents our concluding remarks. 

Not surprisingly, there is no agreed definition of the risk management process. The associated issues and interactions can be very complex, and much effort continues to go into defining how they can be characterised. It is however possible to sketch the overall process into a coherent architecture, based on the principles of ... 

Former National Science Foundation director Neal Lane concurs I have become especially conscious of the discrepancy between the public s interest in, even fascination with, science and its limited knowledge about scientific concepts and issues. 121 He further adds, All scholarly fields—poetry or philosophy, architecture or agriculture—suffer from their separation from the public, although in the case of science, the separation may be more extreme. And yet science and the technology it spawns pervade the very structure of everyone s life... . 

Recent advances in glycobiology have significantly increased interest in nematode glycoconjugates (Dell et al., 1999a,b). As detailed structural analysis deciphers the intricate labyrinth of their molecular architecture, functional issues are beginning to be rationally addressed. It is anticipated that a better understanding of the glycobiology of nematode parasitism... 

The opportunities to develop new structures for computing, quantum computation, and spintronics—together with other areas in molecular electronics—raise important issues about the role of computation in the chemical sciences (Chapter 6). In order for chemical scientists to play a major role in converting clever new ideas for computational devices into full-fledged computers, they will have to become increasingly competent in the architectures, algorithms, and protocols that are necessary for reliable computation. 

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