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71.
The thermodynamic properties of liquid ternary Au-Sn-Zn alloys were measured with an electromotive force (emf) method at four
cross sections with a constant Au to Sn ratio of 9:1, 3:1, 1:1, and 1:3, respectively. At the last three cross sections, calorimetric
measurements were also carried out in order to compare the integral enthalpy of mixing from the direct measurements with the
data of the emf measurements which were derived by Gibbs-Duhem integration. 相似文献
72.
JF Moffat L Zerboni MH Sommer TC Heineman JI Cohen H Kaneshima AM Arvin 《Canadian Metallurgical Quarterly》1998,95(20):11969-11974
The varicella-zoster virus (VZV) genes ORF47 and ORF66 are predicted to encode serine/threonine protein kinases, which are homologs of herpes simplex virus 1 (HSV-1) UL13, and US3. When mutants were constructed by inserting stop codons into ORF47 and ORF66, the recombinants ROka47S and ROka66S, as well as intact ROka replicated in tissue culture. In contrast, inoculation of human thymus/liver or skin implants in SCID-hu mice showed that ORF47 protein was required for viral growth in human T cells and skin. Eliminating ORF66 expression inhibited VZV infectivity for T cells partially but did not impair replication in skin compared with ROka. Infectivity for T cells and skin was restored when ROka47S virus was complemented by insertion of ORF47 into a distant, noncoding site. The ORF47 gene product is the first VZV protein identified as necessary for T cell tropism. It also is essential for skin infectivity in vivo, as is glycoprotein C. Expression of ORF66 did not compensate for the absence of the ORF47 protein. The requirement for ORF47 expression in T cells and skin indicates that this gene product, which is dispensable in vitro, has a critical role within differentiated cells that are essential targets for VZV pathogenesis in vivo. 相似文献
73.
Progressive multifocal leukoencephalopathy (PML), a formerly rare disease, is estimated to occur in up to 5% of all patients with AIDS. The high prevalence of PML in AIDS patients currently enables a comprehensive evaluation of this disorder. We evaluated the clinical and radiographic features of PML in a large cohort of AIDS patients identified by retrospective chart review from 1981 to 1994. Two hundred and five patients were diagnosed with PML of which 154 met the inclusion criteria. Seventy-two (47%) were pathologically confirmed and the remaining 82 (53%) met clinical and radiographic criteria. There was a 12-fold increase in the frequency of PML between 1981-1984 and 1991-1994. PML affected 136 men and 18 women with AIDS. Eighty-four percent of cases were 20-50 years old (range 5 to 68 years). The most common AIDS risk factors were homosexuality (57%) among men and heterosexual transmission (28%) and intravenous drug abuse (28%) among women. In 27% of patients, PML heralded AIDS. Common manifestations included weakness, gait abnormalities, speech disturbance, cognitive disorders, headache, and visual impairment. The CD4 lymphocyte counts exceeded 200 cells in 11% at the time of presentation. Involvement of posterior fossa structures was evident in 48% of cranial magnetic resonance imaging (MRI) studies, but in only 11% of computed tomographies (CT) of the brain. Contrast enhancement, typically faint and peripheral, was seen in 10% of CT scans and 15% of MRIs. The median survival was 6 months and survival exceeded 1 year in 9%. PML is no longer a rare disease. It often heralds AIDS and may occur in the absence of significant decline in CD4 lymphocytes. Survival is generally poor, although prolonged survival beyond 1 year is not unusual. 相似文献
74.
In the present paper research work is presented combining material related research, weld fabrication related research and research in the field of numerical analysis of welded joint performance. Elements belonging to this extensive combination are mechanical testing, fracture mechanics testing of small scale and full thickness specimens, component testing including engineering defect assessment and numerical modelling using finite element method. Examples are given for each of the above mentioned elements. 相似文献
75.
This paper indicates that a variety of models exist to calculate the pressure drop of pneumatic plug conveying. Unfortunately these models are limited in their flexibility and calculate pressure drop only for two extremes, the active and passive case of bulk solid. Until now the stress state within the plug cannot be determined. Therefore a sensor was built to detect wall shear stress, normal stress and the stress state along a moving plug. Beginning with vertical pneumatic plug conveying, the previous models were verified and modified to get new perceptions about formation, stability and pressure drop of plugs.The DFG (German Research Community) is gratefully appreciated for the financial support to this work.Received October 2003 相似文献
76.
Engin A.E. John W. Sommer G. Mathis W. Reichl H. 《Advanced Packaging, IEEE Transactions on》2006,29(3):415-426
In this paper, a stripline model is presented for coupled signal lines routed between a power and a ground plane based on multiconductor transmission line (MTL) theory. Through a suitable diagonalization of the MTL equations for striplines, the transverse electromagnetic (TEM) parallel-plate mode is decoupled from the stripline mode. In this way, stripline models that are obtained assuming ideal planes at ground potential can be extended to take into account the nonideal behavior of the planes. The presented model is applied to represent mode conversion due to vias, holes in the reference planes, and terminations of the stripline. Influence of inhomogeneous media is discussed. 相似文献
77.
78.
Peter Sommer 《Computer Fraud & Security》1997,1997(1):17-18
It is never easy to decide when to publish a book. Against the undoubted benefits of scoring a ‘first’ in a new subject are the undoubted hazards of hitting while the topic is too immature and fast-evolving to be safely encapsulated within a permanent binding. 相似文献
79.
80.
Simon Sommer 《Scientometrics》2005,62(1):165-171
Summary The year 2002 brought a successive funding change-over from until now institutional to programme oriented funding (POF) in the Helmholtz Association of German Research Centres (HGF). This way the 15 German research centres now have to generate their means successively from programmes of the research fields of the HGF (see: www.helmholtz.de) by competing with each other. This nucleus of the reform of the Association is being implemented based upon the opinion of international experts. In this context the evaluation of publications of individual research centres, resp. research groups will be playing an ever increasing part. This lecture will inform about the reformed, partially formalized system and first experiences therewith at the time of the first evaluations. 相似文献