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981.
Cheng-Lin Li Seong-Woo Choi Jeong Mok Oh Jae-Keun Hong Jong-Taek Yeom Joo-Hee Kang Qing-Song Mei Chan Hee Park 《稀有金属(英文版)》2021,(1):20-30
The influence of pre-strain on the formation of bimodal grain structures and tensile properties of a Co-20 Cr-15 W-10 Ni alloy was investigated.The bimodal grain structures consist of fine grains(FGs;2-3 μm in diameter) and coarse grains(CGs;8-16 μm in diameter),which can be manipulated by changing the pre-strain(ε=0.3-0.7) and annealing temperatures(1000-1100℃).High pre-strain applied in the samples can intensify the plasticity heterogeneity through increasing the total dislocation density and the local volumes of high-density dislocations.This can essentially result in finer FGs,a higher FG volume fraction,and overall grain refinement in the samples after annealing.High-temperature essentially increases both the size and volume fraction of CGs,leading to an increase in the average grain size.The tensile test suggests that the bimodal grain structured samples exhibited both high strength and ductility,yield strengths of621-877 MPa and ultimate tensile strengths of1187-1367 MPa with uniform elongations of 55.0%-71.4%.The superior strength-ductility combination of the samples arises from the specific deformation mechanisms of the bimodal grain structures.The tensile properties strongly depend on the size ratio and volume fraction of FGs/CGs in addition to the average grain size in the bimodal grain structures.The grain structures can be modified via changing the pre-strain and annealing temperature. 相似文献
982.
Kyeong Yeol Oh Jin Hwan Lee Marcus J. Curtis-Long Jung Keun Cho Jun Young Kim Woo Song Lee Ki Hun Park 《Food chemistry》2010
The seeds of Psoralea corylifolia were extracted into five different polar solvents: chloroform, 50% ethanol in water, ethanol, methanol and water. All extracts were evaluated for glycosidase inhibitory activity. The chloroform extract (CE) showed the lowest IC50 values against α-glucosidase (82.9 μg/ml) and α-mannosidase (132 μg/ml). Chromatography of CE yielded nine phenolic compounds which were identified as isovabachalcone (1), 4′-O-methylbavachalcone (2), isobavachromene (3), corylifolin (4), bavachinin (5), psoralidin (6), neobavaisoflavone (7), corylifol A (8), and bakuchiol (9). All isolated compounds, apart from compound 5, possessed α-glucosidase inhibitory activities. Among them, compounds 6–8 exhibited potent inhibition with IC50s of 13.7, 27.7 and 11.3 μM, respectively. Furthermore, compounds 2 and 6 showed α-mannosidase inhibitory activity. Mechanistic analysis of their inhibition modes against α-glucosidase showed that compounds (6 and 7) were noncompetitive, whereas compound 8 was mixed. Furthermore, the most active glycosidase inhibitors (2, 6–8) were proven to be present in the native seed in high quantities by an HPLC chromatogram. 相似文献
983.
Corn zein-stearic acid films were laminated to whey powder (WP) and sodium caseinate (SC) mixture (WSM) films. WSM films were prepared at three mass ratios of WP and SC (50:50, 60:40, and 70:30 in w/w) by casting method. WSM films with poor mechanical and barrier properties were produced as the whey powder ratio of WSM increased from 50:50 to 70:30. Corn-zein lamination improved the mechanical and water barrier properties of WSM films by increasing tensile strength (TS) from 4.7-14.5 to 14.0-26.8 MPa and by decreasing water vapor permeabilities (WVP) from 0.432-0.490 to 0.386-0.422 ng m/m2 s Pa. However, elongations of corn-zein laminated films were reduced from 64.5-128.0 to 2.6-4.5%. Mechanical and water barrier properties of corn-zein laminated WSM films were affected by the mass ratio of whey powder to sodium caseinate in WSM films. Addition of stearic acid up to 10 g/100 g of corn zein decreased TS and WVP of laminated films to approximately 12 MPa and 0.36 ng m/m2 s Pa regardless of mass ratio in WSM film. However, no significant differences in TS and WVP were found with further addition of stearic acids. 相似文献
984.
Many inverse heat transfer problems can be solved efficiently through the minimization of a performance function utilizing the conjugate gradient method. The gradient of the performance function needed in the minimization procedure of the conjugate gradient method is obtained by employing either the adjoint variable method or the direct differentiation method. In the present study we consider an inverse problem of estimating time-varying strength of a heat source in a two-dimensional heat conduction system, and compare the adjoint variable method and the direct differentiation method in terms of accuracy and computational efficiency, and finally suggest a new method that exploits the advantageous aspects of both methods while avoiding the shortcomings of them. 相似文献
985.
Hyun-Seog Roh Jong-San Chang Sang-Eon Park 《Korean Journal of Chemical Engineering》1999,16(3):331-337
Both powder-type and film-type mesoporous silica materials have been prepared by using a sol-gel process in highly acidic,
solvent-rich and mild conditions by solvent evaporation method. Powder mesoporous silica which has hexagonal arrays was well
synthesized within only 10 minutes, and mesoporous film was formed on the glass plate within only several seconds by supramolecular
interactions between the silicate species and surfactant-templates. In particular, the synthesis time was very short compared
with that of hydrothermal synthesis owing to the solvent evaporation. This method has some characteristics different from
the hydrothermal method such as the following. There is no precipitation because particles do not form in the solution before
solvent evaporation, bulk powder is rigid, whereas that of hydrothermal synthesis is very soft, and mesoporous materials are
synthesized in acidic condition. Solvent evaporation method for the synthesis of mesoporous materials is promising because
the method is very simple and time-saving. 相似文献
986.
Joo-Hong Choi Soon-Jong Ha Young-Chul Bak Young-Ok Park 《Korean Journal of Chemical Engineering》2002,19(6):1085-1090
In order to investigate the filtration properties of fly ash from a conventional coal power plant, the filtration drag across
the dust cake over an absolute fiberglass filter element was measured. A fluidized bed column was utilized to obtain a well
characterized particle stream. The cake resistance coefficient was analyzed by the equation proposed by Endo et al. [1998]
in order to observe the effect of particle size and polydispersity. The filtration drag was measured for three kinds of particle
stream having the geometric mean particle size of 3.15, 6.07, and 7.83 μm and the geometric standard deviation less than 1.44
in the practical operation conditions for the field applications of face velocity of 0.03–0.06 m/s and area dust load up to
0.2 kg/m2. A dust cake of smaller particle size showed larger pressure drop even though the porosity was higher and presented high
compressibility according to the face velocity. The particle polydispersity was also a dominant factor affecting the compressibility
of the dust cake. 相似文献
987.
Near‐infrared‐active and pH‐responsive fluorescent polymer‐integrated hybrid graphene oxide nanoparticles for the detection and treatment of cancer
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Shazid Md. Sharker Eun Bi Kang Chun‐Im Shin Sung Han Kim Gibaek Lee Sung Young Park 《应用聚合物科学杂志》2016,133(32)
Hybrid nanoparticles for theragnosis have great potentiality to bring desire functionalities in one integrated system. The development of bioimaging guided photothermal therapy (PTT) is pivotal in optimizing cytotoxic cancer therapy. We report near‐infrared (NIR)‐active and pH‐responsive fluorescent, catechol‐conjugated, reduced graphene oxide (rGO)‐anchored hybrid nanoparticles that can sharply increase the photothermal heat in response to NIR exposure and exhibit pH‐dependent fluorescence emission for the detection of tumor areas without causing cell toxicity. The optoelectronic absorption property of poly(3,4‐ethylenedioxythiophene) [PEDOT]:dopamine‐conjugated poly(4‐styrenesulfonate‐co‐maleic acid) [D‐PSM] and 3′,4′‐dihydroxyacetophenone/boron‐dipyrromethene [CCDP/BODIPY]‐quaternized polyethylene glycol grafted poly(dimethylaminoethyl methacrylate) (C/B‐PgP) present in this hybrid nanoparticles resulted in efficient photothermal conversion with pH‐tunable fluorescence that exerted sufficient photothermal cytotoxicity to cancer cells. The in vitro cellular uptake was measured by confocal laser scanning microscopy, allowing the therapeutic efficiency and bioimaging effects to be explored. We expect that the broad optical absorption property of PEDOT:D‐PSM with BODIPY‐conjugated polymers on rGO sheets would get tremendous attraction in this enormous rising PTT with cancer detectable biomarker. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43791. 相似文献
988.
Dispersant‐free dyeing of poly(lactic acid) fabric with temporarily solubilised disperse dyes from azopyridone derivatives
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Poly(lactic acid) fibre is derived from annually renewable crops and known to be 100% compostable. In order to extend its environmental friendliness into the dyeing process, dispersant‐free dyeing of poly(lactic acid) fabric with three temporarily solubilised azo disperse dyes based on hydroxypyridone moiety containing a β‐sulphatoethylsulphonyl group was investigated. The dyes were successfully applied to poly(lactic acid) fabric without the use of dispersants. The colour yields of the dyes on poly(lactic acid) fabric were observed to be dependent on dyebath pH and dyeing temperature. The optimum results were obtained at pH 4–5 and 110 °C. One of the dyes showed a colour yield as good as that of a commercial disperse dye and good build‐up on poly(lactic acid) fabric. All of the dyes could be alkali cleared owing to ionisation of the dye under mild alkaline conditions. Wash fastness was good to very good, and light fastness was good. The chemical oxygen demand levels of the poly(lactic acid) dyeing effluent from the dyes were considerably lower than those from a commercial disperse dye. 相似文献
989.
Effect of Amine Additive for the Synthesis of Cadmium Selenide Quantum Dots in a Microreactor
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Da‐Woon Jeong Basudev Swain Tae‐Yeon Seong Kyoung‐Tae Park Chan Gi Lee Bum Sung Kim 《International Journal of Applied Ceramic Technology》2016,13(2):223-227
The effect of octylamine flow rate on the structure and morphology of CdSe quantum dots synthesized in a microreactor was studied. The flow rate of octylamine was varied from 0.005 ml/min to 0.030 ml/min, and the optical properties of the synthesized particles were analyzed by UV–vis and photoluminescence spectroscopy. The particle size of the quantum dots was found to increase with an increasing octylamine flow rate. Further, UV–vis and photoluminescence bands were found to be red‐shifted with an increasing flow rate. We determined that, by controlling octylamine flow rate, the particle size of the quantum dots could be controlled. This method will help to determine the optimal octylamine flow conditions for synthesizing nanoparticles for use in a diverse range of applications. 相似文献
990.
We investigated the effects of perilla oil containing a high level of α-linolenic acid onin vivo phospholipid metabolism, particularly three subclasses of choline glycerophospholipids (CGP) and ethanolamine glycerophospholipids
(EGP), in rat kidney. After three weeks of feeding, a significantly lower proportion (by 35%) of the alkylacyl subclass of
CGP was found in the perilla oil, as compared to corn oil-fed animals. The alkylacyl species of EGP was also higher in the
perilla oil than in the corn oil-fed animals. These alterations were accompanied by a remarkably lower proportion of arachidonic
acid and a higher level of eicosapentaenoic acid (EPA) in all six subclasses of CGP and EGP in the perilla oil-fed animals.
The levels of linoleic acid were even higher in the diacyl subclasses of CGP and EGP in the perilla oil group, suggesting
that desaturase and elongase enzymes prefer n−3 to n−6 fatty acids as substrates for diacyl species. These data are useful
in defining the effects of α-linolenic acid on the biosynthesis of renal phospholipids and on the replacement of n−6 with
n−3 fatty acids in the six CGP and EGP subclasses. 相似文献