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991.
Poly(vinyl alcohol) (PVA) is an important water-soluble polymer. In this study, a novel method has been developed for preparing water-soluble PVA fiber with narrowly dissolving temperature range via wet spinning of partly acetalized PVA. The structures and properties of the fiber were characterized by IR, 1H-NMR, DSC, WAXD, tensile strength tester, etc. IR and NMR spectra showed that acetal groups were successfully generated on the lateral chains of PVA with the catalysis of acid. As a small quantity of CH2O was added, the introduction of the acetal group could reduce both the hydrophilicity of amorphous region and the crystallinity of PVA water-soluble fiber, and hence narrowed the dissolving temperature range of fiber. However, the dissolving temperature range was broadened with a further increase of CH2O amount, because of the large decrease of crystallinity and crystallite perfection. When the CH2O added amount reached up to 20%, the acetalized PVA was completely insoluble, so that the spinning process could not be carried out. The breaking strengths of most acetalized fibers were beyond 4 cN/dtex, which satisfied the ordinary use of industrial and domestic field. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
992.
In recent years, the conservation of industrial heritage in China has gained increasing attention within the broader context of urban conservation practices. For both policy-makers and scholars, accommodating this industrial heritage will emerge as a pertinent issue for consideration as a growing number of industrial architectural legacies dating from the Republican and Maoist eras come under (re)development pressures. This paper thus traces the development of industrial heritage conservation practices in China and discusses several dilemmas intrinsic to this type of conservation, including issues of authenticity, representativeness, and distinction. Based on comparative case studies from China and other international precedents, this paper also seeks to illustrate the different approaches that could be pursued while still attaining a balance between competing interests and claims. 相似文献
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994.
Adsorption Behavior of Halogenated Anesthetic and Water Vapor on Cr‐Based MOF (MIL‐101) Adsorbent. Part I. Equilibrium and Breakthrough Characterizations
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Ye Hua Nicola Gargiulo Antonio Peluso Paolo Aprea Mladen Eić Domenico Caputo 《化学,工程师,技术》2016,88(11):1730-1738
A synthesized chromium‐based metal organic framework (Cr‐MOF) was used for the adsorption of halogenated anesthetics, i.e., sevoflurane (SF). Adsorption isotherm and breakthrough experiments involving SF (reference sorbate) and water vapor were measured at 298 K and atmospheric pressure on both Cr‐MOF and a commercially used reference adsorbent. The Cr‐MOF MIL‐101 showed a significantly higher SF adsorption capacity and much higher selectivity relative to water vapor compared to the reference adsorbent. Binary‐mixture breakthrough tests demonstrated a “roll‐up effect” for SF on the reference adsorbent while no such effect was observed on MIL‐101. 相似文献
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996.
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998.
Bing Liu Cuizhu Ye Lijing Geng Wei Zhou 《International Journal of Food Science & Technology》2019,54(10):2949-2962
In this study, after purification, the content of betacyanins in dragon fruit peels was 9.22 mg g−1 dry sample. The stability of betacyanins under the effect of different concentration of metal cation (K+, Na+, Cu2+, Fe2+, Fe3+, Mg2+, Al3+) solutions and sugars (glucose, sucrose, fructose, maltose and lactose) solutions was observed. The results showed that 10% lactose and 0.08 mol L−1 potassium chloride solution increased the stability of betacyanins and could be used as stabiliser agents. The degradation reaction under different temperatures (20, 30, 40, 50, 60, 70, 80 °C), pH (2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0) and light conditions (light and dark) of mixed solution (betacyanins and stabiliser), including aqueous pigments solution (APS), lactose pigments solution (LPS) and potassium chloride pigments solution (PCPS), accorded with the first-order reaction kinetics. The t1/2 values (the hours needed for 50.0% degradation of betacyanins) of LPS even up to 330.0 h at 20 °C and dark condition. 相似文献
999.
Perforated blockages with inclined impingement holes are one of the cooling methods that can be used in the trailing edge of gas turbine. This method has a high heat transfer enhancement as well as high frictional resistance. Numerical investigation has been conducted to make a deep insight into the flow fields and pressure distribution of this cooling structure. Split of high heat transfer region has been detected in the impingement region, which may enlarge the thermal stress of metal bulk. The pressure gradient and counter rotating vortex is found to be the mainspring of this phenomenon. Large total pressure dissipation is founded within the impingement chambers. 相似文献
1000.
Effects of droplet characteristics of mist/air cooling on heat transfer for three pin-fin structures are investigated. The round-tip pin-fin structure is newly proposed with partial detachment from one endwall with a round-shaped tip structure. A flat-tip pin-fin with partial detachment and a traditional pin-fin with full attachment serve as references. Reynolds-averaged Navier-Stokes equations and the shear-stress-transport turbulence model are applied. Influences of initial mist temperature, initial mist diameter and initial mist velocity are analyzed in the Reynolds number range 15,000 to 50,000. The round-tip pin-finned channel has highest heat transfer coefficient and lowest pressure loss among the structures. Heat transfer enhancement increases first gradually and then decreases sharply with increasing initial mist diameter but an optimal diameter exists for the highest Nusselt numbers. Nusselt number decreases monotonically with increasing initial mist temperature. Droplet movement and heat transfer are nearly independent of initial mist velocity. 相似文献