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101.
102.
Anwesha N. Fernandes Tim H. Richardson David Lacey Julie Hayley 《Dyes and Pigments》2009,80(1):141-148
Although much solution-based research has been carried out on silicon phthalacyanines, little work has been done on Si Pc LB films. In order to attempt studies on thin films, ultrathin Langmuir–Blodgett films of silicon(IV) phthalocyanine bis(trihexylsilyoxide), C68H94N8O2Si3 have been studied and characterised. Whilst silicon(IV) phthalocyanine bis(trihexylsilyoxide) is not a traditional LB film forming material, it can be made conducive to deposition by mixing with ideal film forming materials such as calixarenes. Surface pressure–area isotherms revealed an area per molecule of around 7.5 Å2 which indicates that the silicon(IV) phthalocyanine bis(trihexylsilyoxide) forms multi-lamella stacks. Thermal optical polarised spectroscopy revealed the formation of brightly coloured mesophases in films. DSC showed the presence of an irreversible A phase and a reversible T phase. 相似文献
103.
M Marcinkiewicz J Marcinkiewicz A Chen F Leclaire M Chrétien P Richardson 《Canadian Metallurgical Quarterly》1999,403(4):471-485
Synthesis of proteins such as nerve growth factor (NGF) is induced after nerve lesion. The NGF precursor (pro-NGF) requires a posttranslational processing by proprotein convertases to become active. In this report, we re-examine the localization of NGF protein and mRNA in injured nerve and show that the candidate pro-NGF convertases furin and PC 7 colocalize with NGF in non-neuronal cells in nerve. By Northern blot analysis, 1.5-kb and 1.3-kb NGF mRNAs were shown to be increased in distal and immediately proximal nerve segments on days 1, 4, and 14 after lesion; by Western blot analysis, NGF proteins of high molecular weight were detected after injury. In vivo, two phases of NGF immunopositivity were observed, in macrophages and perivascular cells shortly after lesion and in endoneurial cells on day 1 and 4. To identify the cells containing NGF, nerve segments were incubated in serum-containing medium with or without conditioning by white blood cells isolated from the circulation. Both hybridization and immunoreactivity signals for NGF were elevated after incubation of nerve segments for 4 hours in conditioned media, so that cells with NGF immunoreactivity could be identified by antibodies to specific cell markers. In these nerve fragments, Schwann cells, perivascular smooth muscle cells, and macrophages contained NGF immunoreactivity. The concentration of furin and PC7 mRNA also increased in lesioned nerves. By immunocytochemical investigation of nerve explants, furin and PC7 were detected in endoneurial cells, macrophages and perivascular cells and were colocalized with NGF. These in vitro and in vivo findings suggest that both furin and PC7 are associated with NGF in several cell types of the sciatic nerve and, hence, may be implicated in intracellular processing of pro-NGF. 相似文献
104.
This paper describes the shear imposed interfacial segregation of release systems for the facilitated attenuation of polyurethane (PU) adhesion to metal coun-terfaces using a RI-RIM system. It is shown that the migration rate of the dispersed release additives due to a shear imposed stress in the resin fluid is much greater than that arising from Fickian diffusion, thereby removing a vital constraint from conventional practice. The novel rotary injection RIM system is presented to simulate the on-line injection and shear induced interfacial segregation in model PU/abherent systems. A wide range of recipes comprising single (liquids or solids) and multicomponent (liquid-liquid and solid-liquid) release materials were injected into the polymerizing resin mixture to provide cohesively weak and friable “particle” boundary layer assemblies at the PU/metal interface. An instrumented Blister Test was employed to evaluate the quality of the molded interfaces in terms of adhesion and the concentration distribution of the injected species in the final cured moldings was determined through high pressure liquid chromatography (HPLC). A comparison of the results on the shear modified and the compounded interfaces confirm an accentuated lateral migration of the additives to the interface resulting in an appreciable diminution in the adhesion of the system. Finally, transport models are suggested to account for the observed augmented transport. 相似文献
105.
The variation in size and concentration of particles in an aerosol over short periods of time has been determined by a photographic techniciue in conjunction with a slit ultramicroscope. The method has been found satisfactory for particle diameters between 0.2 and 4 microns and concentrations up to 107 particles per cubic centimetre. Some of the disadvantages of the ultramicroscope have been overcome and the accuracy and reliability of the results have been assessed. 相似文献
106.
The geometry of turbo-decoding dynamics 总被引:10,自引:0,他引:10
Richardson T. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》2000,46(1):9-23
The spectacular performance offered by turbo codes sparked intense interest in them. A considerable amount of research has simplified, formalized, and extended the ideas inherent in the original turbo code construction. Nevertheless, the nature of the relatively simple ad hoc turbo-decoding algorithm has remained something of a mystery. We present a geometric interpretation of the turbo-decoding algorithm. The geometric perspective clearly indicates the relationship between turbo-decoding and maximum-likelihood decoding. Analysis of the geometry leads to new results concerning existence of fixed points, conditions for uniqueness, conditions for stability, and proximity to maximum-likelihood decoding 相似文献
107.
Concomitant to the liberalisation policy and market reforms in India has been the issue of declining budgetary support for public sector organisations. Hitherto, Indian Railways, the biggest publicly-owned enterprise, has largely been supported by the exchequer. Since the early 1990s, however, the Railways has had to operate increasingly as a commercial rather than a social organisation. One of the ways of improving efficiency is to introduce efficiency-enhancing technologies. This paper is a case study of the introduction of paging technology to the Ratlam Division of Indian Railways. It describes the process of planning and implementation, the HRM implications of the adoption and how the process was successfully managed. It aims at shedding further light on the nature and the processes whereby technologies eventually gain company recognition and acceptance. 相似文献
108.
This article discusses the challenges associated with constructing and managing a telecommunications network capable of supporting the Olympic Winter Games. The importance of the sponsors' role is also outlined. The Salt Lake Organizing Committee (SLOC) is dedicated to bringing the latest technology in telecommunications to the Games without compromising quality and reliability. Telecommunications encompasses much more than telephones normally associated with the traditional definition. Wireless systems, cabling systems, radio, video, and cable TV (CATV) systems, copier, fax, and telex systems, television, and electronics also make up the scope of work for the SLOC team 相似文献
109.
110.
There has been little research on the experiences of students with a hearing loss in mainstream higher education. This investigation compared perceptions of academic quality in 265 students with a hearing loss who were taking courses by distance learning and 178 students taking the same courses who had no declared form of disability. Students who were classified as hard of hearing (rather than deaf) produced significantly lower ratings of the appropriateness of their academic workload than did the students with no declared disability, but the ratings produced by students who were classified as deaf were not significantly different from those produced by the comparison group, In other respects, the students with a hearing loss were remarkably similar to the students with no declared disability in their perceptions of academic quality and their overall satisfaction with their courses, (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献