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991.
The synthesis and properties of individual liquid crystal oligo(cyclosiloxanes),, wherex=4–8 andR is a 4-methoxyphenyl-4-alkyloxybenzoate type of mesogenic group, is described. Preliminary results concerning the effect of ring size on the mesophase formation are included. X-ray diffraction studies have shown that the cyclosiloxanes form a smectic A1 phase.  相似文献   
992.
993.
Jansson R  Arwin H  Lundström I 《Applied optics》1994,33(29):6843-6854
Model calculations on the ellipsometric memory are presented. The ellipsometric memory is an n-bit optical memory whose information is extracted by use of the ellipsometric principle. The memory cells of the device consist of thin-film multilayer structures, and the information of each memory cell is contained in the optical properties of the thin films. Several thin-film multilayer structures were examined in order to find out how different choices of layer materials and other system parameters such as layer thicknesses and wavelength affect resolutions and limitations of the ellipsometric memory. Such calculations are also useful for optimizing the readout resolution. It was found that it is possible to use memory cells having up to at least eight layers, which would permit 8-bit words to be stored at each location. It was also found that, in principle, several types of materials can be used as layer materials, and various aspects of different choices of materials are discussed.  相似文献   
994.
Infrared (350–4000 cm–1) and optical (1.15×104–2.95×104cm–1) spectra, differential thermal analysis (DTA) and d.c. electrical resistivity of FeCl3- doped polyvinylidene fluoride (PVDF) films, over the doping mass fraction range 0 w 0.40, have been measured. The i.r. spectra provided evidence of: (a) the presence of both and phases in the undoped, and a phase in the doped PVDF films; (b) a head-to-head content of 20%; and (c) a different doping mode beyond a 0.25 doping level. The optical spectra resulted in two induced energy bands, and a probable interband electronic transition, due to doping. Dipole relaxation and premelting endothermic peaks were identified by DTA. Electrical conduction is thought to proceed by interpolaron hopping among the polaron and bipolaron states induced by doping. The hopping distance, R o, is calculated according to the Kuivalainen model. A numerical equation is adopted to formulate the dependence of R oon doping level and temperature. It is found that R o< CC separation length. This implies that, in doped PVDF, charge carrier hopping is not an intrachain process.  相似文献   
995.
OBJECTIVE: a) To find the reasons for inadequate use of Hospital Casualty Departments (HCDs); b) to discover the general population's levels of information concerning non-hospital Emergency Services (NESs); c) to analyse the relationship between the type of Primary Care Centre (PCC), i.e. whether reformed or not, and inadequate use of HCDs. DESIGN: A crossover study. SETTING: The Germans Trias i Pujol Hospital Casualty Department, Badalona. PATIENTS: A random sample of 321 patients over 14 years old, who were attended for pathologies considered emergencies not requiring hospital treatment. MEASUREMENTS AND MAIN RESULTS: The variables gathered were: age, gender, where the patient came from, reason for hospital use, knowledge of NESs and subsequent referral. 83.2% of patients attended on their own initiative. The main reasons given were "advantages of a hospital" and "the persistence of symptoms." 49% of the patients stated they knew of the NESs. 80% of the patients proceeded from PCCs which had not been reformed. There were no statistically significant differences (p > 0.05) when the variables "reason for use" and "knowledge of NESs" were compared in relation to where the patient came from (i.e. reformed or non-reformed PCC). CONCLUSIONS: General practitioners in reformed PCCs are less likely to refer to HCDs. Knowledge and use of NESs should be actively supported.  相似文献   
996.
Institute of Nuclear Reactors, Russian Scientific Center "Kurchatovskii Institut." Translated from Atomnaya énergiya, Vol. 76, No. 2, pp. 151–152, February, 1994.  相似文献   
997.
Scientific-Research Physical Chemistry Institute. All-Union Scientific-Research Institute of Automatic Machinery. Institute of Nuclear Reactors, Russian Scientific Center "Kurchatovskii institut." Translated from Atomnaya énergiya, Vol. 76, No. 2, pp. 148–151, February, 1994.  相似文献   
998.
Moscow Scientific and Industrial Association "Radon." Translated from Atomnaya énergiya, Vol. 77, No. 2, pp. 129–134, August, 1994.  相似文献   
999.
Moscow Engineering Physics Institute, MGSU, and Special Design Office "Gidropress". Translated from Atomnaya énergiya, Vol. 77, No. 4, pp. 314–318, October, 1994.  相似文献   
1000.
This chapter focuses on multielectron reactions in organized assemblies of molecules at the liquid/liquid interface. We describe the thermodynamic and kinetic parameters of such reactions, including the structure of the reaction centers, charge movement along the electron transfer pathways, and the role of electric double layers in artificial photosynthesis. Some examples of artificial photosynthesis at the oil/water interface are considered, including water photooxidation to the molecular oxygen, oxygen photoreduction, photosynthesis of amphiphilic compounds and proton evolution by photochemical processes.  相似文献   
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