The cutting forces in the machining of gears with noninvolute teeth are considered, for the example of a triangular tooth profile, by means of robust experiment design and analysis of variance. The rounding radius of the cutter tip has the greatest influence on the cutting force. 相似文献
This paper is the last in the series on the reasearch into the sequential combustion process in a combustor with an outlet gas temperature of 1600 – 相似文献
Protection of Metals and Physical Chemistry of Surfaces - The thermodynamic vacancy model (TVM) of surface energy (SE) leads to the formula of the linear dependence of the minimum SE value of the... 相似文献
Technical Physics Letters - Optimum shape of the capacitance–voltage (C–V) characteristic is a critical parameter determining the efficiency of frequency multiplication in heterobarrier... 相似文献
Technical Physics Letters - A quantum proof of reciprocity relations for nonlinear nonstationary systems in the magnetic field is obtained in the approximation of the Markovian relaxation. 相似文献
The compounds NH4[AnO2(C6H4FCOO3], where An = U (I), Np (II), or Pu (III), CgH4COO? is the 2-fluorobenzoate anion, were synthesized and studied by single crystal X-ray diffraction. Compounds I–III are isostructural and crystallize in the cubic system, space group P213, Z = 4. The main structural units of I–III are mononuclear complexes [AnO2(C6H4COO)3]? belonging to crystal-chemical group AB31 (A = AnO22+, B01 = C6H4FCOO?). The actinide contraction in the structures of I–III is manifested in a regular decrease in the lengths of the An=0 bonds in the AnO22+ cations and in the volumes of the Voronoi-Dirichlet polyhedra (VDPs) of the An atoms in the series U-Np-Pu. The intermolecular interactions in crystal structures of I–III were analyzed by the method of molecular VDPs.
Catalysts Pt/SiO2 with different size of Pt nanoaggregates were studied in catalytic reduction of U(VI) with hydrazine in solutions of H2SO4, HClO4, and HNO3. The catalytic activity of the surface Pt atoms of Pt/SiO2 in this reaction monotonically increases with an increase in the size of metal crystallites on the support, i.e., the negative size effect is observed. Catalytic reduction of U(VI) with hydrazine in H2SO4 solutions is significantly faster than in HClO4 and HNO3, and in HClO4 it is slightly faster than in HNO3. The results were interpreted within the framework of the concept of the energetic nonuniformity of the surface atoms and of the mechanisms of catalytic reduction of U(VI) with hydrazine in acid solutions. 相似文献
The kinetics of development of fatigue microcracks in a high-strength 08Kh14AN4MD steel is studied when a cantilever specimen with several notches is subjected to rotational bending tests. The specific feature of the tests consists in the fact that, when the specimen is loaded at a constant load, different stress amplitudes are realized in different notches. As a result, after the sample has failed across the section with the maximum stress, a longitudinal polished section of the specimen contains fatigue cracks having nucleated in the mouths of the other notches at lower stress amplitudes. A relation between inflection points in the fatigue curve and the conditions of local and developed yield in a notch has been established. Fatigue fracture mechanisms at a superhigh number of loading cycles are studied, and their relation to the structure near a crack is found. A rapid method for estimating the fatigue limit at a superhigh number of loading cycles is proposed. 相似文献
The antimicrobial activity of a combination of lactic acid and whey permeate fermented by a nisin-producing Lactococcus lactis strain was tested by the agar diffusion method using bacteria isolated from fish as test organisms. Lactic acid inhibited all bacterial strains studied, but nisin whey permeate inhibited Gram-positive bacteria only. The combination was more effective than lactic acid alone against Pseudomonas fluorescens and Staphylococcus hominis isolated from fish, and Pseudomonas aeruginosa ATCC9721 and Micrococcus luteus ATCC9341. 相似文献
BACKGROUND: It has been hypothesized that correction of metabolic acidosis might improve the nutritional state of acidotic haemodialysis (HD) patients partly because of a reduced oxidation of branched-chain amino acids (BCAA). AIM: We investigated whether bicarbonate (Bic) supplementation in acidotic HD patients results in increased plasma levels of BCAA. METHODS: In a longitudinal study (run-in period, 2 months; study period, 6 months), the effect of Bic supplementation on plasma levels of BCAA was studied in 12 acidotic HD patients (7 men, 5 women, mean age 54 +/- 18 years) with a predialysis bicarbonate (Bic) concentration smaller or equal to 22 mmol/l. Bic was supplemented by increasing Bic concentration of the dialysate and by oral Bic supplementation. RESULTS: Predialysis Bic increased significantly during the study period (18.7 +/- 2.7 vs. 23.1 +/- 11.5 mmol/l). There was no change in nutritional parameters. However, plasma levels of the BCAA valine, leucine, and isoleucine increased significantly. CONCLUSIONS: In haemodialysis patients with metabolic acidosis, Bic supplementation over a 6-months period resulted in an increase in plasma levels of BCAA. Further study is needed to elucidate the mechanisms behind, and the clinical importance of the observed changes in plasma BCAA levels. 相似文献