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911.
912.
S. Brabetz R. Weidl F. Klemm L. Dörrer F. Schmidl P. Seidel 《Journal of Low Temperature Physics》1997,106(3-4):527-532
We investigated different types of high-Tc DC-SQUID gradiometers with the aim to develop an one-channel heart monitoring system for non-invasive measurements in unshielded
environment. This system could be used to obtain information about the patients condition in serial examinations and in emergency
cases fast and stable. Step-edge and bicrystal Josephson junctions were used to prepare planar galvanically coupled thin film
gradiometers and magnetometers. These sensors were used to carry out measurements in well-shielded and non-shielded environment
and we compared the different noise properties and field gradient resolutions. With different types and sizes of high-Tc DC-SQUID sensors magnetocardiograms were measured in a magnetically shielded room. The influence of antenna configurations,
SQUID parameters, and cooling conditions on the measurement of magnetocardiograms will be discussed. We investigated possibilities
to suppress the earth magnetic field (with pairs of Helmholtz coils) and for noise field compensation in unshielded environment. 相似文献
913.
QP Wang E Escudier F Roudot-Thoraval I Abd-Al Samad R Peynegre A Coste 《Canadian Metallurgical Quarterly》1997,107(7):926-931
Myofibroblasts that express alpha-smooth muscle actin (alpha-SMA) are detected in many chronic inflammatory diseases. Transforming growth factor-beta (TGF-beta) is a potent inducer of myofibroblast accumulation in tissues. In this study, scattered myofibroblasts and TGF-beta were quantified and localized in nasal polyps (NPs) and normal nasal mucosa (NM). NPs were sampled in 16 patients during ethmoidectomy and NM was obtained from 10 control subjects during rhinoplasty. alpha-SMA and TGF-beta were detected using immunohistochemistry and the numbers of labeled cells were quantified (alpha-SMA and TGF-beta indices) and compared between NPs and NM. In eight NPs, in which the pedicle was preserved, alpha-SMA and TGF-beta were evaluated and compared in the pedicle, central, and tip areas. Finally, TGF-beta expression was compared between low (zone 1), moderate (zone 2), and high (zone 3) zones of alpha-SMA positivity. alpha-SMA and TGF-beta indices were significantly higher in NPs than in NM. In the eight selected NPs, alpha-SMA-positive cells were significantly more abundant in the pedicle than in the central and tip areas, whereas TGF-beta-positive cells were significantly more numerous in the pedicle than in the tip area. The number of TGF-beta-positive cells was significantly higher in zone 3 than in zone 1 of alpha-SMA positivity. Myofibroblasts, which are abundant in NPs but rare in NM, could be involved in the growth of NPs by inducing extracellular matrix accumulation. The local development of myofibroblasts in NPs could be controlled by TGF-beta, locally produced by inflammatory cells. 相似文献
914.
Lopez J.F. Eshraghian K. Sarmiento R. Nunez A. Abbott D. 《Solid-State Circuits, IEEE Journal of》1997,32(8):1297-1303
A novel GaAs logic family, pseudodynamic latched logic (PDLL), is presented in this paper. It is composed of a dynamic circuit where the logic is performed and a static latch whose function is to permanently refresh the stored data on a dynamic node. Because of this hybrid structure, PDLL takes advantage of both static and dynamic families and thus, permits implementation of very complex structures with good speed-area power tradeoff. Moreover, the inclusion of the latch permits this class of logic family to be highly efficient for pipelined systems working even at high temperature without loss of data due to leakage currents. Barrel-shifters, programmable logic arrays (PLA's), and carry lookahead adders (CLA's) were verified by simulations demonstrating its feasibility for the development of high-performance very large scale integration (VLSI) systems 相似文献
915.
The purpose of this study was to assess the use, in computer-mediated communication, of the strategic message structuring tactic known as framing. Interlocutors in computer-mediated environments have software supported systemic resources facilitative of constructing messages using framing tactics in their argumentative discourse. It is hypothesized that framing strategies are related to the emotional tenor of a disputant's message and that a speaker's emotional involvement with an issue should be curvilinearly related to the appropriation of framing as an argumentative discourse strategy. Results from the analysis of 3000 messages, obtained from a diverse sampling of computer-mediated discussion groups and forums, provided support for the primary hypothesized relationship. A speaker's emotional involvement was significantly and curvilinearly related to two message framing devices (message dependency and coalition building) and a measure of conciliatory face-saving moves. 相似文献
916.
On overview on the state of the art and future trends in physics-based electron device modelling for the computer-aided design of monolithic microwave ICs is provided. After a review of the main physics-based approaches to microwave modeling, special emphasis is placed on innovative developments relevant to circuit-oriented device performance assessment, such as efficient physics-based noise and parametric sensitivity analysis. The use of state-of-the-art physics-based analytical or numerical models for circuit analysis is discussed, with particular attention to the role of intermediate behavioral models in linking multidimensional device simulators with circuit analysis tools. Finally, the model requirements for yield-driven MMIC design are discussed, with the aim of pointing out the advantages of physics-based statistical device modeling; the possible use of computationally efficient approaches based on device sensitivity analysis for yield optimization is also considered 相似文献
917.
918.
Future developments in cosmetic formulations 总被引:1,自引:0,他引:1
T.F. TADROS 《International journal of cosmetic science》1992,14(3):93-111
In recent years, there have been a great deal of interest in applications of microemulsions, liposomes (vesicles) and multiple emulsions in cosmetic formulations. These systems will provide the cosmetic industry with new types of formulations which are easier to apply, better functional benefit and potentially safer formulations. Microemulsions are thermodynamically stable systems and hence shelf life is no problem. Many cosmetic ingredients can be adequately solubilized in the swollen micelles of the microemulsions. Such solubilized systems may enhance transport and diffusion through various barriers, eg., the skin, thus enhancing the efficacy of the formulations. However, microemulsions may cause skin irritation by disrupting the liquid crystalline structure of the stratum corneum. This problem may be overcome by formulating microemulsions, which on evaporation produce lamellar liquid crystalline structures. The problem of skin irritation is certainly reduced or eliminated using liposomes or vesicles, which offer an alternative to microemulsions. The principles for formation and stabilization of vesicles are discussed in this paper and research work is needed to produce nanocapsules from liposomes, using polymerizable surfactants. Multiple emulsions of the water/oil/water (w/o/w) or oil/water/oil (o/w/o) types are also valuable systems for formulating cosmetics. In the first place, they offer a means of sustained release of the various ingredients. Secondly, they allow one to separate the various ingredients in the formulation, thus preventing their possible interaction. The basic principles required for preparation of stable multiple emulsions are summarised. Developments of polymeric surfactants led to the formulation of stable multiple emulsions. An example of a recently formulated stable w/o/w multiple emulsion is given in this paper The stability of the system was investigated using optical microscopy. Creaming occurred on storage, particularly at high temperature (40°C) and this was significantly reduced by addition of Kelzan (a polysaccharide with high molecular weight). The final formulation was studied rheological techniques. 相似文献
919.
920.
Pearton S.J. Ren F. Katz A. Fullowan T.R. Abernathy C.R. Hobson W.S. Kopf R.F. 《Electron Devices, IEEE Transactions on》1992,39(1):154-159
The use of rapid isothermal processing (RIP) is detailed for each of the three annealing steps in the fabrication of heterostructure-based devices such as heterojunction bipolar transistors (HBTs). RIP can be used for the alloying of ohmic metal contacts, annealing of ion-bombarded regions for device isolation or parasitic capacitance reduction, and for conventional implant activation annealing. High-speed (f T=65 GHz) HBTs were achieved using RIP for all of the required heating steps. The authors compare the use of several types of silicon carbide-coated graphite susceptors for eliminating slip formation on 2- and 3-in-diameter GaAs wafers during high-temperature implant activation annealing 相似文献