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991.
The origins of poor CD (cross machine) moisture profiles In tissue production are discussed generally. CD line force distribution at the first and second presser roll has a significant influence on the CD moisture profile. The crowning of cylinder and presser rolls compensates for the deformation of the Yankee cylinder shell (due to nip load, internal steam pressure and hood operating conditions) and of the presser rolls but only for any one given operating condition. However, during operation the parameters often have to be varied. in a sensitivity analysis the resulting CD line force deviations were calculated and typical figures are given here to demonstrate the relative effect. The shape of the resulting line load curves are drawn and from these the typical shape of the resulting CD moisture- profile can be derived. Means for possible control such as controllable presser rolls, sectionally adjustable hoods and steam boxes as well as eddy current and infra-red -heating are discussed and evaluated.  相似文献   
992.
The electroplating of Ni-Cd alloy coatings was carried out from alkaline baths (pH 10). For comparison, electroplating of the parent metals, Ni and Cd, was performed individually under the same conditions. The cathodic current efficiency for codeposition was high and decreased with increasing current density. The codeposition process is an anomalous type of plating with Cd being the preferentially deposited metal. The Ni content in the deposits increased with increasing current density. This increase in Ni content improves the corrosion resistance and microhardness of the deposits. X-ray diffraction analysis showed that the deposits consist of a mixture of Ni, β, γ, γ1 phases.  相似文献   
993.
Translated from Izmeritel'naya Tekhnika, No. 4, pp. 38–39, April, 1989.  相似文献   
994.
995.
This paper describes the work done by the Autonomous Systems Lab of Ecole Polytechnique Federale de Lausanne (EPFL) on the global design of an unmanned solar airplane that can fly continuously over days and night. Part of the Sky-Sailor Project, a first prototype was designed and demonstrated to have very good flight characteristics. The prototype achieved an autonomous flight of five hours with its energy only from the sun. A lightweight control and navigation system was also designed for the aircraft.  相似文献   
996.
The structure of DNA sequences homologous to the viral myc oncogene from ovarian tumours, intact tissues and the same patients peripheral blood leukocytes has been studied. The Southern blot analysis of malignant tumour DNA reveals amplification of c-myc protooncogene of 3 from 11 patients. Metastases DNAs of two from those patients also contain multiple copies of c-myc. No myc gene amplification has been detected in 6 examined benign ovarian tumours. The presence of extra copies of myc-related sequences has been shown in two from three DNA samples from peripheral blood leukocytes of patients with ovarian cancer.  相似文献   
997.
The effect of adenosine on pulmonary vessels was studied in isolated perfused rat lungs. Drugs were administered intra-arterially in a fixed volume of 0.1 ml Krebs solution as bolus injections. Adenosine responses were obtained before and 10 min after drug injections. When applied in logarithmically increasing doses (1-100 micrograms/ml), adenosine caused dose-dependent increases in pulmonary perfusion pressure (e.g. pulmonary vasoconstriction) which were readily reversible. Challenging adenosine with quinidine, dihydroergocristine and cyproheptadine (2 micrograms/ml each) did not significantly alter adenosine responses. Pretreatment of lungs with 0.5 mM theophylline, 10 micrograms/ml indomethacin, 30 micrograms/ml tebokan (a PAF antagonist) or 1 microgram/ml methylene blue for 10 min, however, antagonized the vasoconstrictor effect of the drug significantly. From these experiments, it was concluded that the mechanisms underlying the pulmonary vasoconstrictor action of adenosine are complex, and that both types of purinoceptors, prostaglandins, PAF and other vascular endothelial hormones might be involved.  相似文献   
998.
999.
An annular slot-coupled dielectric resonator antenna is investigated experimentally. As compared with the previous rectangular-slot version, the new configuration offers a much wider bandwidth of 18%. The return loss, radiation patterns, and antenna gain of the configuration have been measured and are discussed  相似文献   
1000.
Methods and equipment successfully employed in high- temperature calorimetry to measure partial and integral enthalpies of mixing in liquid oxide systems are reviewed with special attention given to the drop-mixing method. This technique has been used to measure enthalpies of mixing in binary liq-uid mixtures composed of network forming oxides (e.g. SiO2) and network modifying oxides (e.g. Na2O). Results for the systems Na2O-SiO2 and Na2O- B2O3 are presented graphically. Entropies of mixing were estimated by combining enthalpies with available data on Gibbs energies of mixing. Prominent thermochemical features of glass-forming oxide melts are pointed out. The observed thermodynamic behavior is discussed in relation to its structural basis.  相似文献   
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