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排序方式: 共有106条查询结果,搜索用时 15 毫秒
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An epoxy–cardanol resin was developed using epichlorohydrin, bisphenol-A and cardanol. On evaluation it was found that epoxy–cardanol resin exhibits better properties as compared to epoxy resin in terms of increase in tensile strength, elongation, bond with steel and lowering of water vapour transmission of the film. The improvement in these properties indicated that the paints based on modified resin would be more durable than the epoxy based paints. Accordingly, paints were formulated using the developed resin and their performance were compared with their counterparts made with unmodified epoxy resin. Zinc powder, zinc phosphate, micaceous iron oxide and synthetic iron oxide were used as pigments along with fillers, additives and an aromatic polyamine adduct hardener. For both types of paints similar doses of pigments and additives were used. Physico-mechanical properties, chemical resistance and corrosion protection efficiency of the formulated paints were determined. It was found that the anticorrosive properties of epoxy–cardanol resin based paints are superior to that of the paints formulated with the unmodified epoxy resin. Micaceous iron oxide based paints in epoxy–cardanol resin showed the best performance followed by zinc phosphate based paints. It is concluded that the developed resin is a better binder media for the formulation of paints. 相似文献
3.
Michel Tielemans Patrice Roose Chinh Ngo Roberto Lazzaroni Philippe Leclère 《Progress in Organic Coatings》2012
The waterborne nature of radiation curable polyurethane dispersions largely respond to the current environmental concerns and do not require any additional coalescent since the film formation (drying) and hardening (photo-curing) take place in distinct steps. It is possible to design aqueous dispersions with distinct polymer particle populations resulting in micro-structured coatings with optimized properties over a wide range of curing conditions. Mixed dispersions based on hard and soft acrylated polyurethane particles were used as model systems for the present study. The minimum film formation temperature has been investigated as a function of the hard:soft polymer ratio. The elastic modulus of the dry coatings shows a reinforcing effect consistent with the inclusion of hard domains in a soft continuous matrix. However, the level of reinforcement is not properly predicted by the usual mechanical models and it is qualitatively accounted for by assuming a composition gradient (interphase) between the hard domains and the matrix. The multiple-phase structure was clearly established by Atomic Force Microscopy in agreement with thermal analysis data. Furthermore the local nanoscale mechanical properties were mapped using a new imaging mode based on real-time force–distance curve analysis. Finally, the coatings prepared using this multiple-phase pattern present a clear benefit over conventional homogeneous coatings by offering an improved balance of chemical and mechanical resistance in pigmented systems applied on melamine-coated MDF panels. 相似文献
4.
The development of coloured self-compacting concrete (C-SCC) opens new fields of application, since it adds attractive alternatives for challenging architectural designs in terms of shapes and colour, to the already versatile aesthetic characteristics of traditional coloured concrete. The benefits of using cement paste or mortar tests as a previous step in SCC design to optimize mixture proportions have been recognized. This paper shows the advantages of using a mortar-based mix design methodology for C-SCC. In addition to rapid and easy determination of the proportions of the mixtures including different types of pigments, cements, mineral additions, and chemical admixtures, the mortar approach enables observation of the effect of pigments on the viscosity of C-SCC and evaluation of specific aspects as the colorimetric parameters, the colour homogeneity and the surface finishing. 相似文献
5.
The aim of this work was to analyse and tentatively identify anthocyanin species in red cabbage using HPLC/DAD-ESI/Qtrap MS. The extraction was realized by using a pressurized liquid technique and the separation of the pigments was achieved by a high resolution liquid chromatography system with a 1.8 μm particles C-18 column. Photodiode array detection was employed to determine the UV/Vis spectral characteristic of the pigments. Electrospray ionization-linear ion trap mass spectrometry allowed the specific determination of the fragmentation patterns of the anthocyanins, by performing different ion scan modes. Twenty four anthocyanins were separated and identified, all having cyanidin as aglycon, represented as mono- and/or di-glycoside, and acylated, or not, with aromatic and aliphatic acids. Nine anthocyanins were identified for the first time in red cabbage. 相似文献
6.
To investigate the interrelation between the orientation of platelet-like effect pigments in surface coatings and their coloristic properties, two metallic basecoat systems (Al, Al–blue mixture) have been deliberately blended with a colorless organic extender (nearly spherical), that allows for a systematic disturbance of the alignment of the pigment particles. As methods of investigation, goniospectrophotometry, confocal Laser-scanning microscopy, and microscopic image analysis of basecoat cross-cuts have been employed. From the reflection-indicatrix, the variation of colorimetrical quantities with deorientation agent content have been derived in a direct way. Moreover, the phase-function of the Al-pigments has been determined from fitting the equation of radiative transfer to the experimental reflection surfaces. The phase-function provides information about the distribution function of polar angles of the pigment particles in 3-dimensional space. The distribution function of the orientation angle of Al-pigments in cross-cuts of basecoats as obtained from microscopic image analysis can be satisfactorily explained within a simulation model, that allows for a calculation of the distribution function for when assuming the individual distribution functions for polar- and azimuthal-angle of the surface normal of the pigment particles, taking fully into account induced axes of anisotropy. 相似文献
7.
《食品与生物技术学报》1996,15(3)
用不同保色溶液对胡萝卜、青椒和菜豆进行预处理,得出了其干制品色素保存率的最佳预处理方案,并讨论了金属离子预处理对青椒和菜豆的保绿效果,以及硫化处理对胡萝卜的保色效果。 相似文献
8.
T. Mayer U. Weiler D. Schlettwein D. Wöhrle M. Kunst 《Solar Energy Materials & Solar Cells》2007,91(20):1873-1886
Hybrid materials of silicon and organic dyes have been investigated for possible application as photovoltaic material in thin film solar cells. High conversion efficiency is expected from the combination of the advantages of organic dyes for light absorption and those of silicon for charge carrier separation and transport. Low temperature remote hot wire chemical vapor deposition (HWCVD) was developed for microcrystalline silicon (μc-Si) deposition using SiH4/H2 mixtures. As model dyes zinc phthalocyanines have been evaporated from Knudsen type sources. Layers of dye on μc-Si and μc-Si on dye films, and composites of simultaneously and sequentially deposited Si and dye have been prepared and characterized. Raman, absorption, and photoemission spectroscopy prove the stability of the organic molecules against the rough HWCVD-Si process. Transient microwave conductivity (TRMC) indicates good electronic quality of the μc-Si matrix. Energy transfer from dye to Si is indicated indirectly by luminescence and directly by photoconductivity measurements. FxZnPc pigments with x=0,4,8,16 have been synthesized, purified and adsorbed onto H-terminated Si(1 1 1) for electronic state line up determination by photoelectron spectroscopy. For x=4 and 8 the dye frontier orbitals line up symmetrically versus the Si energy gap offering similar energetic driving forces for electron and hole injection, which is considered optimum for bulk sensitization and indicates a direction to improve the optoelectronic coupling of the organic dyes to silicon. 相似文献
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10.
Avocado (Persea americana) is an important tropical fruit, but little is known about their antioxidant capacities and phytochemical composition. The objective of this research was to determine antioxidant capacities, total phenolic content and identify and quantify major antioxidant compounds in avocados of different strains and cultivars. Ripe Florida avocados from seven cultivars (Slimcado, Booth 7, Booth 8, Choquette, Loretta, Simmonds, and Tonnage) of West Indian or Guatemalan strains were separated into seeds, peels and pulp, and freeze dried. Hass avocado of Mexican strain was chosen for comparison. Samples were extracted with acetone/water/acetic acid solvent and analysed using the Folin–Ciocalteu assay for total phenolic content. Antioxidant capacities were determined by oxygen radical absorbance capacity (ORAC) and DPPH assays. Procyanidins were identified and quantified using HPLC-MSn. Antioxidant pigments (chlorophylls and carotenoids) were estimated spectrophotometrically. For all varieties, seeds contained the highest antioxidant capacities, phenolic content, and procyanidins, whereas the pulp had the lowest. Procyanidins, including catechin, epicatechin, A- and B-type dimers, A- and B-type trimers, tetramers, pentamers and hexamers, were identified in peels and seeds using normal-phase HPLC–ESI-MSn. Antioxidant capacities, phenolic contents and procyanidins in avocados were highly correlated, suggesting that procyanidins were the major phenolic compounds that contributed to antioxidant capacities. Carotenoids and chlorophylls were found to be concentrated in avocado peels but did not correlate with antioxidant capacities. This study suggested that avocado seeds and peels, industrial wastes of avocado processing, can be exploited as source of antioxidants. 相似文献