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1.
The 13C NMR chemical shifts for 4-oxo-1,3-dioxolane (1) and its all methyl-substituted derivatives (2-10) as well as for 5-oxo-1,3-oxathiolane (11) and its nine alkyl-substituted derivatives (12-20) are reported. The magnitude and variety of the substituent effects are in accordance with the envelope conformations in which the oxygen or sulfur atom locates at the tip of the envelope as postulated on the basis of earlier data. 相似文献
2.
Gerhard Post Jeffrey H. Kingston Samad Ahmadi Sophia Daskalaki Christos Gogos Jari Kyngas Cimmo Nurmi Nysret Musliu Nelishia Pillay Haroldo Santos Andrea Schaerf 《Annals of Operations Research》2014,218(1):295-301
We present the progress on the benchmarking project for high school timetabling that was introduced at PATAT 2008. In particular, we announce the High School Timetabling Archive XHSTT-2011 with 21 instances from 8 countries and an evaluator capable of checking the syntax of instances and evaluating the solutions. 相似文献
3.
Tuomas Mehtiö Leena Nurmi Virpi Rämö Ali Harlin Jarmo Ropponen 《European Polymer Journal》2012,48(4):774-778
A series of copolymers of glycolic acid (GA), d,l-lactic acid (dl-LA) and d,l-2-hydroxybutyric acid (dl-2HBA) were prepared via melt condensation polymerization. The utilized monomers represent mixtures that are present and potentially obtainable from kraft black liquor by fractionation. Polymerizations were performed in 165 °C at nitrogen atmosphere and reduced pressure using stannous octoate as catalyst. Copolymerizations were conducted with varying dl-2HBA content in order to observe how the presence of the dl-2HBA monomer affects the properties of the polymers. Prepared copolymers were characterized with 1H NMR and 13C NMR, size exclusion chromatography, differential scanning calorimetry and thermogravimetric analysis. The obtained copolymers had molecular weights between Mw = 3500–10,000 g/mol. dl-2HBA had a lowering effect on the glass transition temperatures and molecular weights of the copolymers. However, significant lowering of molecular weight was observed only when the amount of dl-2HBA in the feed exceeded 60%. The results indicate that dl-2HBA can be copolymerized with GA and dl-LA and therefore the corresponding kraft black liquor fractions can be utilized for polymerizations. 相似文献
4.
Kimmo Nurmi Dries Goossens Jari Kyngäs 《The Journal of the Operational Research Society》2014,65(11):1770-1779
This paper presents a method to schedule a triple round robin tournament, which involves minitournaments, each hosted by one team. A key issue is that at the end of the season the number of home games should be balanced over the teams, despite the fact that in minitournament matches only the host team plays at home. This format is played in the Finnish national ice hockey league for players under the age of 20 years, where the problem is further complicated by many other constraints, for example, preassigned matches resulting from away tours that should limit the distances travelled by the teams. To obtain a schedule for this league, we sequentially solve four distinct combinatorial problems. This method allows us to construct a schedule for the 2009–2010 season, which is superior to the official schedule: it has no hard constraint violations, and outperforms the official schedule on three of five soft constraints. 相似文献
5.
Kalevi Pihlaja Mauri Eskonmaa Raimo Keskinen Alpo Nikkil Timo Nurmi 《Magnetic resonance in chemistry : MRC》1981,17(4):246-249
The 13C NMR chemical shifts for 1,3-dithiolane and 13 methyl substituted derivatives are reported. Substituent effects are derived and compared with those for cyclopentanes and 1,3-dioxolanes. The magnitude and variety of the substituent effects are best explained with the aid of a half-chair conformation where the S-1? C-2? S-3 plane passes between C-4 and C-5. 相似文献
6.
Titanium is a strong, corrosion resistant metal with low mass density, making it ideal for various purposes, including aviation and medical applications. In the present work, the elastic properties of titanium have been investigated using the first principles Exact Muffin-Tin Orbitals method. The focus of our study is the anisotropic elasticity of single-crystal and cold-rolled titanium. Both types of titanium are used in industrial applications because of their special mechanical properties compared to randomly ordered polycrystalline alloys. Single crystals have better creep resistance compared to polycrystalline metals, while cold-rolled ones, on the other hand, possess more strength. Here cold-rolled titanium is investigated for the first time using ab initio calculations. Single-crystal results are obtained directly from first principles total energy calculations, whereas the elasticity of the cold-rolled structure is estimated from the single-crystal data. The elasticity of cold-rolled titanium has previously been investigated only experimentally, and thus the present computational approach provides new insight and valuable complementary information, not only for cold-rolled titanium, but also for more complex structures. Our results are found to be in good agreement with experimental findings and therefore serve as a starting point for investigating the elasticity of titanium alloys, which, using our method, can be accomplished as easily as the pure titanium case. 相似文献
7.
Densities, partial molar volumes, and viscosities of aqueous solutions of betaine have been measured at 5, 10, 15, 20, 25,
30, 37, and 45 °C over the concentration range 0.05 to 5.0 mol⋅L−1. The partial molar volumes show that betaine exists partly as a monohydrate and partly in its anhydrous form. The proportion
of the anhydrous form increases with increasing temperature. Also, an associated form of betaine appears in concentrated betaine
solutions, possibly with water as a bridging group. The significance of the viscosity B-coefficient is discussed. The signs of B
st, the increment of the viscosity B-coefficients arising from structural changes of water, are negative and the signs of dB/dT, the temperature derivative of B, are positive. These results show that betaine is a water structure breaker especially at lower temperatures, and this effect
decreases to insignificance at higher temperatures. The ionization equilibria of betaine were investigated in aqueous 0.5 mol⋅L−1 and 1.0 mol⋅L−1 NaNO3 at 5, 15, 25, and 37 °C by a potentiometric method. Using the least-square computer program SUPERQUAD, the complex forms
are deduced to be betanium BH, bis(betanium) BHB, and bis(betaine) B2 or bis(betaine)hydrate BH2OB. 相似文献
8.
9.
James T. Nurmi Vaishnavi Sarathy Paul G. Tratnyek Donald R. Baer James E. Amonette Abhi Karkamkar 《Journal of nanoparticle research》2011,13(5):1937-1952
Most methods currently being used to recover Fe0-core/oxide-shell nanoparticles from solutions (including the solvents they are synthesized or stored in) are potentially
problematic because they may alter the particle composition (e.g., depositing salts formed from solutes) or leave the particles
prone to transformations during subsequent storage and handling (e.g., due to residual moisture). In this study, several methods
for recovery of nanoparticles from aqueous solution were studied to determine how they affect the structure and reactivity
of the recovered materials. Simple washing of the nanoparticles during vacuum filtration (i.e., “flash drying”) can leave
up to ~17 wt% residual moisture. Modeling calculations suggest this moisture is mostly capillary or matric water held between
particles and particle aggregates, which can be removed by drying for short periods at relative vapor pressures below 0.9.
Flash drying followed by vacuum drying, all under N2, leaves no detectable residue from precipitation of solutes (detectable by X-ray photoelectron spectroscopy, XPS), no significant
changes in overall particle composition or structure (determined by transmission electron microscopy, TEM), and negligible
residual moisture (by thermogravimetric analysis, TGA). While this improved flash-drying protocol may be the preferred method
for recovering nanoparticles for many purposes, we found that Fe0-core/oxide-shell nanoparticles still exhibit gradual aging during storage when characterized electrochemically with voltammetry. 相似文献
10.
Victor Kisonen Chunlin Xu Roger Bollström Jonas Hartman Hille Rautkoski Maristiina Nurmi Jarl Hemming Patrik Eklund Stefan Willför 《Cellulose (London, England)》2014,21(6):4497-4509
A major enhancement of grease and water vapor barrier properties was accomplished with a 1–10 g/m2 coating of O-acetyl galactoglucomannan (GGM) ester or with GGM coatings applied as water dispersions on cartonboard. GGMs were esterified with phthalic and benzoic anhydrides, respectively. The novel phthalic esters of GGM (GGM-Ph) were characterized with HPLC, NMR, and matrix-assisted laser desorption/ionization with mass spectrometry (MALDI-TOF-MS). The degree of substitution of GGM-Ph was obtained by 1H NMR, 13C NMR, and HPLC. The GGM esters and GGM were coated onto cartonboard, and they demonstrated good moisture and very good grease resistance even with thin 1–3 g/m2 coatings. The time for penetration of 0.1 % rapeseed oil was 54 h with the 2.4 g/m2 coating thickness. The lowest water vapor transmission value was 39 g/m2/24 h with 9.7 g/m2 coating. The GGM esters had clearly higher water resistance and slightly higher grease barrier values than native GGM. High-molar-mass-based GGM (50 kg/mol) and GGM-Ph rendered better water vapor and grease barrier properties than low-molar-mass GGM (9 kg/mol) and GGM-Ph. The GGM-based coatings can be safely used on an industrial scale as water was used as a solvent. As obtained from non-food-based side-stream wood-based resources, GGM and GGM esters project a sustainable and modern conception for barrier purposes in food packaging. 相似文献