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61.
Fernando Hernando Kristine Lally Diego Ruano 《Applicable Algebra in Engineering, Communication and Computing》2009,20(5-6):497-507
We consider matrix-product codes ${[C_1\cdots C_s] \cdot A}$ , where ${C_1, \ldots , C_s}$ are nested linear codes and matrix A has full rank. We compute their minimum distance and provide a decoding algorithm when A is a non-singular by columns matrix. The decoding algorithm decodes up to half of the minimum distance. 相似文献
62.
Oscar A. Ruano Jeffrey Wolfenstine Jeffrey Wadsworth Oleg D. Sherby 《Journal of the American Ceramic Society》1992,75(7):1737-1741
The creep behavior of single-crystalline MgO tested in the 〈100〉 direction is reviewed in the temperature range 1300° to 1800°C. At low stresses, the stress exponent is equal to about unity, and the deformation process is attributed to Harper–Dorn creep. At high stresses, the stress exponent is equal to approximately 5 and the deformation process is attributed to dislocation glide controlled by climb. The creep behavior in both regions is successfully predicted by an internal stress model for Harper–Dorn creep. 相似文献
63.
Gabriel Beltrán María T. Ruano Antonio Jiménez Marino Uceda María P. Aguilera 《European Journal of Lipid Science and Technology》2007,109(3):193-197
Bitterness is an important sensory attribute of virgin olive oil (VOO). It is usually assessed by tasting, which is a time‐consuming method and needs trained tasters. Bitterness is related to the phenolic compounds and can be estimated by the measurement of the specific absorbance at 225 nm (K225). This paper proposes to evaluate oil bitterness intensity as estimated from the K225 values measuring the phenol content. A significant relationship between phenol content and K225 as well as a prediction model for bitterness intensity estimation from the phenol content was obtained. Classification of oil bitterness was based on the phenol content. Furthermore, when 12 VOO samples were classified by their bitterness intensities as estimated by the prediction model and by sensory analysis, more than 92% of the oil samples were correctly classified. Therefore, by measuring the phenol content, the bitterness intensity can be estimated and oils can be classified by their bitterness. This model may represent an easy method to evaluate the bitterness intensity without any sensory assessment. 相似文献
64.
Levy IK Mizrahi M Ruano G Zampieri G Requejo FG Litter MI 《Environmental science & technology》2012,46(4):2299-2308
Heterogeneous photocatalytic reduction of As(V) and As(III) at different concentrations over TiO(2) under UV light in deoxygenated aqueous suspensions is described. For the first time, As(0) was unambiguously identified together with arsine (AsH(3)) as reaction products. As(V) reduction requires the presence of an electron donor (methanol in the present case) and takes place through the hydroxymethyl radical formed from methanol oxidation by holes or hydroxyl radicals. On the contrary, As(III) reduction takes place through direct reduction by the TiO(2)-conduction band electrons. Detailed mechanisms for the photocatalytic processes are proposed. Although reduction to solid As(0) is convenient for purposes of As removal from water as a deposit on TiO(2), attention must be paid to formation of AsH(3), one of the most toxic forms of As, and strategies for AsH(3) treatment should be considered. 相似文献
65.
C.M. Cepeda-Jiménez J.M. García-InfantaO.A. Ruano F. Carreño 《Journal of Alloys and Compounds》2011,509(35):8649-8656
Tensile tests were conducted to evaluate the influence of equal-channel angular pressing (ECAP) on the mechanical properties at room temperature of overaged Al 7075-O alloy. ECAP processing was performed using route BC at different temperatures and number of passes, i.e. different processing severity conditions. The maximum load (Fmax) recorded during the last pass of each ECAP path considered in this study is a very good estimation of the processing severity. The mechanical properties were studied in terms of the balance between tensile strength and ductility. In the processed Al 7075-O alloy, the grain size was reduced down to ∼150 nm. Consequently, tensile testing at room temperature revealed a significant increase in the maximum tensile strength after ECAP with respect to the as start material. In the present study, as the processing severity increases with the number of ECAP passes or with the decrease in processing temperature, there is a consistent trend of increment in ultimate tensile strength with minor decrease in uniform plastic elongation respect to the first ECAP pass at room temperature. This is in contrast to the behaviour after more severe plastic deformation conditions, where an increase in strength together with a strong decrease in elongation would be expected. 相似文献
66.
F. Carre o M. Torralba M. Eddahbi O.A. Ruano 《Materials Science and Engineering: A》1997,230(1-2):116-123
Research on the high temperature creep behavior of three rapidly solidified Al-Fe-X-Si (where X = Cr, Mn or Mo) dispersion strengthened materials with three different alloying compositions has been conducted. Firstly, microstructural examinations have been carried out on the as-received, thermally treated and tested samples. The microstructure consists of a fine Al matrix embedding small round-shaped Al12(Fe,X)3Si and Al13(Fe,X)4 dispersoids. Grain sizes ranging from 0.85 to 1.45 μm and dispersoid sizes ranging from 45 to 54 nm were observed. Secondly, tensile tests were performed at high temperature from 573 to 823 K at strain rates ranging from 2.5×10−6 to 10−2s−1. The experimental data exhibited high apparent stress exponent, nap, and high activation energy, Qap. The rnicrostructure remained stable and fine after testing. The results are analyzed by means of various models used in the literature. 相似文献
67.
Pulmonary surfactant protein A (SP-A) is synthesized by type II cells and stored intracellularly in secretory granules (lamellar bodies) together with surfactant lipids and hydrophobic surfactant proteins B and C (SP-B and SP-C). We asked whether the progressive decrease in pH along the exocytic pathway could influence the secondary structure and lipid binding and aggregation properties of porcine SP-A. Conformational analysis from CD spectra of SP-A at various pH values indicated that the percentage of alpha-helix progressively decreased and that of beta-sheet increased as the pH was reduced. The protein underwent a marked self-aggregation at mildly acidic pH in the presence of Ca2+, conditions thought to resemble those existing in the trans-Golgi network. Protein aggregation was greater as the pH was reduced. We also found that both neutral and acidic vesicles either with or without SP-B or SP-C bound to SP-A at acidic pH as demonstrated by co-migration during centrifugation. However, the binding of acidic but not neutral vesicles to SP-A led to 1) a striking change in the CD spectra of the protein, which was interpreted as a decrease of the level of SP-A self-aggregation, and 2) a protection of the protein from endoproteinase Glu-C degradation at pH 4.5. SP-A massively aggregated acidic vesicles but poorly aggregated neutral vesicles at acidic pH. Aggregation of dipalmitoylphosphatidylcholine (DPPC) vesicles either with or without SP-B and/or SP-C strongly depended on pH, being progressively decreased as the pH was reduced and markedly increased when pH was shifted back to 7.0. At the pH of lamellar bodies, SP-A-induced aggregation of DPPC vesicles containing SP-B or a mixture of SP-B and SP-C was very low, although SP-A bound to these vesicles. These results indicate that 1) DPPC binding and DPPC aggregation are different phenomena that probably have different SP-A structural requirements and 2) aggregation of membranes induced by SP-A at acidic pH is critically dependent on the presence of acidic phospholipids, which affect protein structure, probably preventing the formation of large aggregates of protein. 相似文献
68.
Texture measurements of the as-received rolled Al-6%Cu-0.4%Zr alloy revealed that a copper component, {311}<233>, is developed at the surface and a S component, {631}<113>, is formed at the middle of the sheet. During early stages of superplastic deformation at 480 °C/5×10−4 s−1 the intensity of the Cu component increases slightly whereas the S component changes toward the brass component Bs, {110}<112>, by a slip process. For larger strains, both components decrease by a grain boundary sliding mechanism. 相似文献
69.
Gregory B. Kharas Katherine Kim Kimberly C. Beinlich Sarah B. Benington Sarah K. Brennan Michelle Morales Norman E. Ruano Doo Y. Won Emanuel Adibu Kenneth Watson 《Polymer Bulletin》2000,45(4-5):351-357
Summary
Methyl 2-cyano-3-dihalophenyl-2-propenoates, R2C6H3CH=C(CN)CO2CH3 (R2= 2,4-difluoro, 2,5-difluoro, 2,6-difluoro, 3,4-difluoro, 3,5-difluoro, and 2-chloro-6-fluoro), were prepared by the piperidine
catalyzed Knoevenagel condensation of corresponding disubstituted benzaldehydes and methyl cyanoacetate. Novel copolymers
of the propenoates and styrene were prepared at equimolar monomer feed by solution copolymerization in the presence of a radical
initiator. The order of relative reactivity (1/r
1) was 2,5-difluoro (2.11) > 2,6-difluoro (1.84) > 3,5-difluoro (1.71) > 2,4-difluoro (1.4) > 3,4-difluoro (0.65) > 2-chloro-6-fluoro
(0.59). The copolymers were characterized by IR, 1H and 13C NMR, GPC, DSC and TGA. High glass transition temperatures of the copolymers compared that of polystyrene indicates a substantial
decrease in chain mobility of the copolymers due to the high dipolar character of the trisubstituted ethylene monomer unit.
Received: 12 June 2000/Revised version: 12 September 2000/Accepted: 12 September 2000 相似文献
70.
Maider García de Cortazar Felix Peñalba Elena Silveira Xabier Gómez-Mitxelena Manuel Carsí Oscar A. Ruano 《International Journal of Material Forming》2017,10(3):379-387
Hot workability of Ti-6%Al-4%V and two whisker discontinuously reinforced materials, Ti-6%Al-4%V/1.2%TiB and Ti-6%Al-4%V/8.9%TiB, have been investigated. Hot uniaxial compression tests were carried out using a computer controlled thermomechanical simulator Gleeble machine at temperatures in the range 850 °C to 950 °C and strain rates ranging from 1 to 50 s?1. The microstructures and the compression test results were compared among the three materials. The Ti-6%Al-4%V/8.9%TiB material presented extensive cracking after deformation. In contrast, the Ti-6%Al-4%V/1.2%TiB material showed an interesting compromise between flow stress and workability. The parameters of the Garofalo equation were calculated for the three materials revealing apparent activation energies that increased with increasing TiB content. The modelling is carried out by stability maps that gives the temperature at a given strain rate to obtain optimal workability and the stresses that has to bear the equipment. Taken 5 s?1 as a reference strain rate, the temperature required to obtain a quality product increased from about 1143 K (870 °C) for the Ti-6-4 alloy without TiB to 1228 K (955 °C) for the 1.2%TiB and to 1283 K (1010 °C) for the 8.9%TiB material. Therefore, the production of parts of the TiB composites should be conducted at a higher forming temperature to avoid the presence of cracks. 相似文献