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71.
The x-ray diffraction technique has been used to measure surface residual stress in Ti-6Al-4V samples subjected to shot peening
(SP), laser shock peening (LSP) and low plasticity burnishing (LPB). The magnitude, spatial and directional dependence and
uniformity of the surface residual stresses have been investigated. The results show that residual stresses due to SP are
uniform and independent of direction. LSP has been observed to produce non-uniform residual stress varying from one region
to another, and also within a single laser shock. In the case of LPB, residual stresses have uniform spatial distribution
but have been observed to be direction-dependent. Various components of the residual stress tensor in the LPB sample have
been determined following the Dolle-Hauk method. The results of the residual stress due to three surface treatments are compared,
and possible reasons for spatial and directional dependence are discussed. 相似文献
72.
Prasad Mutyala Veera Venkata Vara Rao Radha Hunasenahalli Raghavendra Veeranna Vadde Chennupalli Venkata Suryanarayana Sathish Byrappa 《Russian Journal of General Chemistry》2021,91(12):2522-2526
Russian Journal of General Chemistry - Novel quinolone derivatives have been designed and readily synthesized according to a simple protocol including O-alkylation and Claisen rearrangement... 相似文献
73.
Yadav JS Boyapelly K Alugubelli SR Pabbaraja S Vangala JR Kalivendi SV 《The Journal of organic chemistry》2011,76(8):2568-2576
The first total synthesis of recently isolated diacetylene alcohols oploxyne A, oploxyne B, and their C-10 epimers was accomplished. The structure of natural oploxyne B has been revised. The key steps involved are base-induced double elimination of a carbohydrate-derived β-alkoxy chloride to generate the chiral acetylenic alcohol and Cadiot-Chodkiewicz cross-coupling reaction. The target compounds displayed potent cytotoxicity against neuroblastoma and prostate cancer cell lines. 相似文献
74.
Chernyshova IV Ponnurangam S Somasundaran P 《Journal of the American Chemical Society》2011,133(24):9536-9544
The impact of deposition and aggregation on (bio)chemical properties of semiconducting nanoparticles (NPs) is perhaps among the least studied aspects of aquatic chemistry of solids. Employing a combination of in situ FTIR and ex situ X-ray photoelectron spectroscopy (XPS) and using the Mn(II) oxygenation on hematite (α-Fe(2)O(3)) and anatase (TiO(2)) NPs as a model catalytic reaction, we discovered that the catalytic and sorption performance of the semiconducting NPs in the dark can be manipulated by depositing them on different supports or mixing them with other NPs. We introduce the electrochemical concept of the catalytic redox activity to explain the findings and to predict the effects of (co)aggregation and deposition on the catalytic and corrosion properties of ferric (hydr)oxides. These results offer new possibilities for rationally tailoring the technological performance of semiconducting metal oxide NPs, provide a new framework for modeling their fate and transport in the environment and living organisms, and can be helpful in discriminating between weakly and strongly adsorbed species in spectra. 相似文献
75.
76.
Aluminum chloride addition results in a self-organized TURN-ON fluorescence of 3-hydroxyflavone (3HF) by a complexation reaction
in MeOH and subsequent ligand exchange reaction with fluoride or acetate ions causes a fluorescence TURN-OFF of this complex,
delivering a quantitative estimation route for fluoride and acetate ions. The ternary complex of 3HF with Al (III), a hard
acid provides for a sensitive signalling system for fluoride ion, a hard base in the concentration range from 6 μM to 50 mM
by a concerted co-ordination of fluoride ion involving an intermediate mechanistic pathway, while the complex is sensitive
to acetate addition between 0–68 μM. The ligand exchange reaction of Al (3HF)2 complex by fluoride or acetate ion, without interference from other common anions, has been investigated by UV-visible and
fluorescence spetroscopies. The structure of the in-situ intermediate isolated at higher Al (3HF)2 complex and acetate concentrations was inferred from the FT-IR spectrum and ESI-MS of the sample. 相似文献
77.
GaN nano flowers were grown on various commercial substrates by a simple catalyst free chemical vapor deposition (CVD) technique. The size and shape of the nanostructures were characterized by scanning electron microscopy (SEM). The influence of the substrate, growth temperature, and ammonia flow rate on the size and shape of the nano-flowers were investigated along with their anti-reflective and hydrophobic properties. The normal incident reflectivity measurements carried out on the nano structures showed very low (5%) reflectivity. The wettability of the surface investigated by the static contact angle of water droplet revealed their hydrophobic nature with a large contact angle of about 145°. These results on catalysis-free nanostructures would be useful for anti-reflective surfaces/coatings in solar cell applications. 相似文献
78.
Masataka?Sugimoto Kengo?Ishizuka Keisuke?Hatano Sathish?K.?Sukumaran Yuji?AokiEmail author 《Rheologica Acta》2017,56(10):779-785
The viscoelastic properties of poly(methyl methacrylate) (PMMA)/grafted poly(butyl acrylate) (PBA) nanoparticle systems were investigated. The rubber particles consist of PBA core (60 nm in diameter) and grafted PMMA shell. The grafting degree, defined as the weight ratio of grafted PMMA to PBA particles, ranges from 0.8 to 1.5. Two series of samples, A series with 7.5 wt.% of PBA content and B series with 12 wt.% of PBA content, were used. The systems exhibited fast and slow relaxation process, the former reflecting the relaxation of the matrix PMMA chains and the latter being attributed to grafted PBA particles. For A series samples, time-temperature superposition (TTS) was held well over the frequency (ω) and temperature (T) ranges measured. However, for B series samples, TTS was not satisfied at low ω due to the particle-particle interaction of grafted PBA particles, although the samples obeyed TTS at high ω associated with the relaxation with entanglement of matrix PMMA. At high T and low ω region, the B series samples showed a sol-gel transition at elevating T and the critical gel behavior characterized with a power-law relationship, G′ = G″/tan(nπ/2) ∝ ωn, was observed. This behavior suggested formation of a self-similar, fractal structure of grafted PBA particles. The critical gel temperature (T gel) and the critical exponent (n) were determined for the B series samples. TEM observations revealed that as-prepared A and B samples had well-dispersed particles but the B samples after viscoelastic measurements had fragmented networks of the PBA particles, confirming that the sol-gel transition occurred for the PMMA/grafted PBA systems at elevating T. 相似文献
79.
Silk finds an important place for its elegance, softness, luster, sheen, strength, uniformity suitable for the production of respective valuable textile garments and apparels. Due to the amphoteric character of silk protein polymer, the overall behavior of silk will be enriched when it is applied with natural resources. Based on these considerations, it is proposed in this research work to treat mulberry silk fabric with recovered sericin protein in addition with natural finishing sources like aloevera, amla and nochi in varied combinations followed by coloration with some selected natural sources. After these applications, the silk fabric was undergone for some testing for the determination of color value, fastness behavior, tensile strength, absorbency character, anti-odor and retention aspects, and FTIR graphs. The outcome of the results are convinced to the expectations suitable for the applications in the textile industries for garment and apparel utilities. 相似文献
80.
Anju Chopra Dheer Singh Wadhawa Ram Kalsi Vatsala Sugumaran Amarjit Singh Sarpal Biswajit Basu 《Chromatographia》2009,70(7-8):1143-1146
GC/FID has been used for the determination of a fatty acid based lubricity improver in diesel fuel. The method makes use of phase transfer catalysis for the enrichment of the lubricity improver from the diesel matrix. The use of phase transfer catalysis for the simultaneous extraction, preconcentration and derivatisation of the fatty acids enables determination of concentrations of 20 mg L?1. The method has been successfully applied to the analysis of diesel streams from various sources. The effect of the diesel matrix has also been investigated and it does not affect the recovery of the additive. 相似文献