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41.
Titanium/AlPO materials were prepared by grafting a titanium alkoxide (titanium isopropoxide) onto a mesoporous aluminophosphate. The structures of the surface-bound titanium species were investigated by UV–vis, FTIR, MAS NMR, and XANES/EXAFS spectroscopies. The titanium anchoring occurs by reaction between the alkoxide precursor and surface Al–OH and P–OH groups of the AlPO support. The titanium species exist in isolated tetrahedral coordination environments, and as oligomerized species. The catalysts prepared are selective and active for the liquid-phase epoxidation of cyclohexene in the presence of TBHP. The observed activities and selectivities were comparable with those obtained for similarly prepared titanium/SBA-15 samples of similar Ti content (but higher BET surface area). 相似文献
42.
A series of star-shaped poly(lactic acid)s with carboxylic acid terminal groups have been synthesized by direct poly-condensation of lactic acid in the presence of a poly-carboxylic acid core molecule with triphenylphosphonium trifluoromethanesulfonate (TPP-T) catalyst.These star-polymers had thermal properties not very much different from those of star-shaped poly(lactic acid) with hydroxyl terminal groups and linear poly(lactic acid), irrespective of the structure of the core molecule and number of polymer arms. Solubility and degradability of these star-polymers were, however, greatly enhanced compared to those of star-polymers with hydroxyl terminal groups and increased depending on the number of polymer arms. From the star-shaped polymers, a variety of ammonium salts and the corresponding carboxyamides were successfully prepared. 相似文献
43.
44.
Tomoyo Okumura Kenya Sonobe Asami Ohashi Harumi Watanabe Katsushi Watanabe Hiroshi Oyamada Masaaki Aramaki Toshiaki Ougizawa 《Polymer Engineering and Science》2020,60(7):1699-1711
Simultaneous one-pot syntheses of PA66 and HAp were carried out by extracting H2O and CO2 from PA66 monomers and HAp raw materials, respectively, resulting in the formation of a polyamide (PA) 66-hydroxyapatite (HAp) nanocomposite. During the process, a spherical nano-sized HAp particle was precipitated following dissolution of micro-sized CaHPO4・2H2O. The PA66 monomers were subsequently adsorbed onto the generated HAp product. Some of the adsorbed PA66 monomers formed a bound polymer on HAp, and an increase in the adhesiveness of the PA66-HAp interface was observed as the polymerization progressed. During this process, the synthesis of a nanocomposite from a micro-sized raw material and creation of an autonomous strong interface between the matrix and filler was achieved. In addition, the shape of the resultant HAp was controllable and could be modified to needle shape by the addition of F− and Mg2+ ions to the raw material. HAp could also be changed to plate shape via octa-calcium phosphate (OCP). Notably, during the synthesis, the filler shape of the nanocomposite could be controlled to 0D (particle), 1D (needle), and 2D (plate). 相似文献
45.
Nguyen Chi Trung Ngo Hironari Sugiyama Buddhika Amila Kumara Sodige Juan Paulo Wiff Satoru Yamanaka Yoonho Kim Tsuneo Suzuki Masaaki Baba Masatoshi Takeda Noboru Yamada Koichi Niihara Tadachika Nakayama 《Journal of the American Ceramic Society》2023,106(1):201-212
The energy-harvesting ability of the lead-free ferroelectric Ba(Zr,Ti)O3 was investigated and greatly enhanced using the Kim novel electrothermodynamic cycle for low-temperature application. Ba(Zr,Ti)O3 was synthesized with a Zr:Ti ratio of 10:90 (BZT10) by hot-press sintering, which exhibited a mix relaxor-ferroelectric behavior. For power generation using the Kim cycle with low and high temperatures of TL = 25°C, TH = 120°C, the most optimized temperature pattern occurred for a heating time of 12.5 s and a cooling time of 22.5 s. Under these conditions, the electric field increased during the novel isodisplacement process, and the displacement variation in the isoelectric step reached the highest value and maximized the BZT10 cycle loop area. Applying these conditions while lowering TL to 20°C, an energy density ND = 504 mJ/cm3 was achieved. This value is the highest obtained energy density in a practical test for lead-free ferroelectric bulk material in the BaTiO3 family. 相似文献
46.
High oleic acid oil suppresses lung tumorigenesis in mice through the modulation of extracellular signal-regulated kinase cascade 总被引:2,自引:0,他引:2
Yamaki T Yano T Satoh H Endo T Matsuyama C Kumagai H Miyahara M Sakurai H Pokorny J Shin SJ Hagiwara K 《Lipids》2002,37(8):783-788
This study was undertaken to estimate the effect of dietary high oleic acid oil (OA) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone
(NNK)-induced lung tumorigenesis in mice. Diet containing 10% oil was fed to mice through experimental periods. On day 30
after NNK injection (100 mg/kg body weight, i.p.), the treatment increased the level of prostaglandin E2 (PGE2) as well as proliferating cell nuclear antigen, a marker of cell proliferation in a high linoleic acid oil (LA)-fed group
but not in an OA-fed group. The NNK treatment also induced the activation of an extracellular signal-regulated kinase (Erk)
cascade (Erk, Mek and Raf-1) in an LA-fed group. On the other hand, OA feeding abolished the NNK-induced activation of the
Erk cascade. In conjugation with these events, OA feeding reduced lung tumor incidence and tumor multiplicity (percentage
of mice with tumors) in mice compared with LA feeding at the 20th experimental week. These results suggest that OA suppresses
lung tumorigenesis and that this suppression is correlated with the inhibition of PGE2 production and inactivation of the Erk cascade. 相似文献
47.
Toshihiro Nagao Yuji Shimada Yoshie Yamauchi-Sato Takaya Yamamoto Masaaki Kasai Kentaro Tsutsumi Akio Sugihara Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2002,79(3):303-308
A commercial product of CLA contains almost equal amounts of cis-9,trans-11 (c9,t11)-CLA and trans-10,cis-12 (t10,c12)-CLA. We attempted to enrich the two isomers by a two-step selective esterification using Candida rugosa lipase that acted on c9,t11-CLA more strongly than on t10,c12-CLA. An FFA mixture containing CLA isomers was esterified with an equimolar amount of lauryl alcohol in a mixture of 20%
water and the lipase. When the esterification of total FA reached 50%, two isomers were fractionated in a good yield: t10,c12-CLA was enriched in FFA, and c9,t11-CLA was recovered in lauryl esters. The FFA were esterified again to enrich t10,c12-CLA. At 27.3% esterification of total FA, the t10,c12-CLA content in FFA increased to 64.8 wt% with 89.3% recovery: The ratio of the content of t10,c12-CLA to that of two isomers was 95.9%. Lauryl esters obtained by the single esterification were employed for enrichment
of c9,t11-CLA. After the esters were hydrolyzed, the resulting FFA were esterified again with lauryl alcohol. At 62.0% esterification
of total FA, the c9,t11-CLA content in lauryl esters increased to 73.3 wt% with 79.4% recovery: The ratio of the content of c9,t11-CLA to that of two isomers was 95.6%. In a 600-g-scale purification, molecular distillation was effective in separating
the reaction mixture into lauryl alcohol, FFA, and lauryl ester fractions. 相似文献
48.
Preparation, Structure, and Properties of Thermally and Mechanically Improved Aluminum Titanate Ceramics Doped with Alkali Feldspar 总被引:3,自引:0,他引:3
Masahide Takahashi Masahiro Fukuda Masaaki Fukuda Hisato Fukuda Toshinobu Yoko 《Journal of the American Ceramic Society》2002,85(12):3025-3030
Aluminum titanate (AT) ceramic materials doped with alkali feldspar ((Na0.6 K0.4 )AlSi3 O8 ) have been prepared. These ceramics exhibited high sinterability, large resistance to thermal decomposition, and large flexure strength. The existence of liquid-phase feldspar at sintering temperatures promoted the formation of AT ceramics as the sintering agent. It was considered that silicon ions substituting for aluminum ions at the surface of AT crystal grains lowered the surface energy and hindered the diffusion of Ti4+ and Al3+ , giving rise to the large resistance to thermal decomposition. As a result, doping with alkali feldspar was found to effectively improve the mechanical and thermal properties of AT ceramics. 相似文献
49.
When a predatory mite, Amblyseius womersleyi is present, Tetranychus kanzawai takes refuge on its webs during a quiescent stage. To examine the factors responsible for the antipredator behavior of T. kanzawai, we exposed T. kanzawai to the odor of conspecifics, A. womersleyi, and both T. kanzawai and A. womersleyi. The proportion of T. kanzawai females that took refuge was significantly higher when they were exposed to the odor of `both T. kanzawai and A. womersleyi.' Furthermore, the proportion of T. kanzawai females that took refuge was significantly higher when they were exposed to injured conspecifics than to intact conspecifics. These results suggest that T. kanzawai assesses predation risk, at least in part, by using the odor of injured conspecifics. 相似文献
50.
Hideto Matsuyama Kentarou Hayashi Taisuke Maki Masaaki Teramoto Noboru Kubota 《应用聚合物科学杂志》2004,93(1):471-474
Microporous high‐density polyethylene (HDPE) and low‐density polyethylene (LDPE) hollow fiber membranes were prepared from polyethylene–diisodecyl phthalate solution via thermally induced phase separation. Effect of the polyethylene density on the membrane structure and performance was investigated. The HDPE membrane showed about five times higher water permeability than the LDPE membrane because it had the larger pore and the higher porosity at the outer membrane surface. The formation of the larger pore was owing to both the initial larger structure formed by spinodal decomposition and the suppression of the diluent evaporation from the outer membrane surface due to the higher solution viscosity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 471–474, 2004 相似文献