다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

This critical review provides a processing-structure-property perspective on recent advances in cellulose nanoparticles and composites produced from them. It summarizes cellulose nanoparticles in terms of particle morphology, crystal structure, and properties. Also described are the self-assembly and rheological properties of cellulose nanoparticle suspensions. The methodology of composite processing and resulting properties are fully covered, with an emphasis on neat and high fraction cellulose composites. Additionally, advances in predictive modeling from molecular dynamic simulations of crystalline cellulose to the continuum modeling of composites made with such particles are reviewed (392 references).

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Cellulose nanomaterials review: structure, properties and nanocomposites

Cellulose fibrils with widths in the nanometer range are nature-based materials with unique and potentially useful features. Most importantly, these novel nanocelluloses open up the strongly expanding fields of sustainable materials and nanocomposites, as well as medical and life-science devices, to the natural polymer cellulose. The nanodimensions of the structural elements result in a high surface area and hence the powerful interaction of these celluloses with surrounding species, such as water, organic and polymeric compounds, nanoparticles, and living cells. This Review assembles the current knowledge on the isolation of microfibrillated cellulose from wood and its application in nanocomposites; the preparation of nanocrystalline cellulose and its use as a reinforcing agent; and the biofabrication of bacterial nanocellulose, as well as its evaluation as a biomaterial for medical implants.

Nanocelluloses: A New Family of Nature-Based Materials

Correction for ‘One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate’ by Sergiu Coseri et al., RSC Adv., 2015, 5, 85889–85897.

/pdf/one-shot-carboxylation-of-microcrystalline-cellulose-in-the-49ojwia11o.pdf

One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate

The effect of electrolyte (NaHCO3) concentration on the adsorption of poly-DADMAC (poly-diallyldimethylammonium chloride) onto cellulosic fibers with different charge profiles was investigated. Surface carboxymethylated fibers were obtained by grafting carboxymethyl cellulose (CMC) onto the fiber surface and bulk carboxymethylated fibers were obtained by reacting the fibers with monochloroacetic acid. It was shown that nonionic interactions do not exist between cellulose and poly-DADMAC, rather electrostatic interactions govern the adsorption. Charge stoichiometry prevails under electrolyte-free conditions, whereas surface charge overcompensation occurs at higher electrolyte concentrations. It was shown that charge stoichiometry prevails if the thickness of the electric double layer κ-1 was larger than the mean distance between the charges on the fiber surface, as predicted by polyelectrolyte adsorption theories, taking lateral correlation effects into account. In a second set of experiments the ESCA tech...

On the indirect polyelectrolyte titration of cellulosic fibers. Conditions for charge stoichiometry and comparison with ESCA.

Chemical factors affecting the behaviour of fibres during papermaking

Adsorption of cationic polyacrylamides onto monodisperse polystyrene latices and cellulose fiber: Effect of molecular weight and charge density of cationic polyacrylamides

The effect of topochemical attachment of CMC to the surface of bleached softwood kraft pulp on the paper strength properties was examined. The strength development was compared with the effect of beating the reference pulp in a PFI-mill. The effect of topochemical surface modification on the water retention properties (WRV) of the pulps was also investigated. This topochemical modification was shown to give a substantial strength development as far as rupture properties (tensile index, strain to failure and tensile energy absorption) were concerned, whereas elastic properties were less affected. Neither the sheet density nor the light scattering coefficient was affected by the attachment of CMC onto the fibres. The effects were interpreted in terms of improved specific bond strength. In this context, the measured WRV of CMC-treated fibres probably does not reflect the swelling of the fibres, but rather the conformation of CMC on the surface of the fibres. The conformation collapsed when the sodium counter-ion was ion-exchanged to calcium, i.e. the WRV decreased significantly. However, the sheet properties were unaffected by this ion-exchange, which demonstrates that the water in this layer does not affect sheet consolidation or sheet properties.

Studies on topochemical modification of cellulosic fibres - Part 2. The effect of carboxymethyl cellulose attachment on fibre swelling and paper strength

Tom Lindström

Papers

One-shot carboxylation of microcrystalline cellulose in the presence of nitroxyl radicals and sodium periodate

On the indirect polyelectrolyte titration of cellulosic fibers. Conditions for charge stoichiometry and comparison with ESCA.

Chemical factors affecting the behaviour of fibres during papermaking

Adsorption of cationic polyacrylamides onto monodisperse polystyrene latices and cellulose fiber: Effect of molecular weight and charge density of cationic polyacrylamides

Studies on topochemical modification of cellulosic fibres - Part 2. The effect of carboxymethyl cellulose attachment on fibre swelling and paper strength