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1.
This paper discusses the relationships studied between manifold solids and r-sets by defining an r-set as a decomposition in two-manifold cells. This decomposition is represented as a graph (Two-manifold Cell Decomposition graph TCD) in which each node corresponds to a 2 manifold component of the regular set, while each arc or hyperarc defines a non-manifold adjacency between components. The TCD model and data structure encoding it were designed in order to be compatible with a traditional boundary architecture. 相似文献
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When dissolved in ethyl oleate secondary ozonide, both C60 and C70 fullerenes undergo a series of epoxidation reactions. The pseudofirst-order kinetic rate constants of this process were determined spectrophotometrically at various temperatures and the activation energy for C60 epoxidation through ethyl oleate ozonide was found at 25.9 kcal/mol. Furthermore, C60 was found more reactive than C70 with the ozonide. The kinetics rate constants of C60 epoxidation with ethyl oleate ozonide were compared with the C60 photo-oxidation and auto-oxidation determined in pure ethyl oleate. The epoxidation of fullerenes starts from the homolysis of the peroxide group of the 1,2,4-trioxolane ring of ethyl oleate secondary ozonide. Thus, it is suggested that fullerenes have a potential as decomposition agents of secondary ozonides in some technological applications. 相似文献
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Sacha inchi (Plukenetia volubilis L.) shell: an alternative source of phenolic compounds and antioxidants
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Rosana Chirinos Ornella Necochea Romina Pedreschi David Campos 《International Journal of Food Science & Technology》2016,51(4):986-993
Sacha inchi seed (SI) is known as a rich source of oil with high content of polyunsaturared fatty acids of the ω‐3 and ω‐6 type (~85% of total fatty acids). However, few studies have focused on the use of by‐products from the seed. The aim of this study was to characterise the main phenolic families present in SI shell and to evaluate the best extraction solvent for the extraction of phenolic compounds (PC) and antioxidant capacity (AOXC). The PC content corresponded to 74.5 ± 5.1 mg g?1 of which 93.1% were condensed tannins and the remaining compounds corresponded to free and bound phenolic acids, hydrolyzable tannins, flavonoids and flavanoids. Protocatechic and p‐coumaric acids but also hydroxycinammic acid derivatives of ferulic and o‐coumaric type and lignan derivatives were identified. Acetone containing solvents favoured the extraction of higher amounts of total PC and AOXC. This study highlights the potential use of SI shell as a novel and alternative source of PC antioxidants for the nutraceutical and/or functional food industries. 相似文献
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Franco Cataldo Mihai V. Putz Ornella Ursini Giancarlo Angelini 《Fullerenes, Nanotubes and Carbon Nanostructures》2016,24(6):400-405
Two samples of activated carbon fabrics (ACF) with very high surface area (>1300 to >1800 m2/g) fully ozonized in the part 1 of this study were analyzed by thermogravimetric analysis (TGA) coupled both with differential thermal analysis (DTA) and FT-IR spectroscopy (TGA-FTIR). The adsorbed water and the amount of oxygenated functional groups were determined. The ozonized ACF shows an exothermal decomposition at about 181–189°C which may be due at least in part to the decomposition of ozonide and/or peroxide groups. The TGA-FTIR has revealed that the main products released from the thermal decomposition are CO2 followed by CO. Formic acid was detected only in correspondence to the exothermal transition at 181°C and was taken as a proof of the decomposition of secondary ozonides. 相似文献
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Most studies on surface-initiated controlled polymerizations for the synthesis of polymeric covalent organic-inorganic hybrid materials focus on chemical methods requiring specific modifications of the inorganic substrate. Few mechanistically-aware approaches have been undertaken towards exploiting the reactivity of defects induced by physical techniques such as ionizing radiations or UV–Vis light. Within this framework, we take grafted polymerization of styrene from γ-irradiated silica as a mechanistic testing ground where para- and diamagnetic silica defects are present, and polymerization proceeds through both radical and cationic mechanisms, resulting in a bimodal molecular weight distribution. We show that these mechanistic intricacies can be sorted out by resorting to the chemical arsenal developed in the last decades for controlled polymerizations. Specifically, we obtained a silica-polystyrene grafted material by cationic grafting from at 30 °C, a unimodal molecular weight distribution, and a relatively high molecular weight (Mn = 7.4 kDa) with a PDI of 1.68. 相似文献
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Franco Cataldo Mihai V. Putz Ornella Ursini Giancarlo Angelini D. Anibal Garcia-Hernandez Arturo Manchado 《Fullerenes, Nanotubes and Carbon Nanostructures》2016,24(3):195-201
It is shown that graphite oxide (GO) and both heavily ozonized C60 and C70 fullerenes, known as “fullerene ozopolymers,” are paramagnetic materials with a very strong electron spin resonance (ESR) signal at room temperature. When thermally annealed, the paramagnetic centers are gradually lost in large part. This occurs at 350°C in the case of GO, while for fullerene ozopolymers, a higher temperature is required, reaching the same results in the end. The half-width of ESR signal is linked to the distribution of paramagnetic centers. Once again, striking analogies were found in the half-width of the ESR signal measured on GO and fullerene ozopolymers, at least in the temperature range of 25–450°C. Similarly, the same g-factor values, which are diagnostic for understanding the chemical nature of paramagnetic centers, were found on both GO and fullerene ozopolymers in all ranges of temperature considered. 相似文献
10.
S. Bertoldi S. Farè M. Denegri D. Rossi H. J. Haugen O. Parolini M. C. Tanzi 《Journal of materials science. Materials in medicine》2010,21(3):1005-1011
In bone tissue reconstruction, the use of engineered constructs created by mesenchymal stem cells (MSCs) that differentiate
and proliferate into 3D porous scaffolds is an appealing alternative to clinical therapies. Human placenta represents a possible
source of MSCs, as it is readily available without invasive procedures and because of the phenotypic plasticity of many of
the cell types isolated from this tissue. The scaffold considered in this work is a slowly degradable polyurethane foam (EF
PU foam), synthesized and characterized for morphology and in vitro interaction with chorion mesenchymal cells (CMCs). These
cells were isolated from human term placenta and cultured onto the EF PU foam using two different culture media (EMEM and
NH osteogenic differentiation medium). Synthesized EF PU foam showed homogeneous pore size and distribution, with 89% open
porosity. In vitro tests showed CMCs scaffold colonization, as confirmed by Scanning Electron Microscopy (SEM) observations
and hematoxylin–eosin staining. Alizarin Red staining revealed the presence of a small amount of calcium deposition for the
samples treated with the osteogenic differentiation medium. Therefore, the proposed EF PU foam appears to stimulate cell adhesion
in vitro, sustaining CMCs growth and differentiation into the osteogenic lineage. 相似文献