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981.
Facile purification of tocopherols from soybean oil deodorizer distillate in high yield using lipase 总被引:16,自引:0,他引:16
Yuji Shimada Seiichi Nakai Masaharu Suenaga Akio Sugihara Motohiro Kitano Yoshio Tominaga 《Journal of the American Oil Chemists' Society》2000,77(10):1009-1013
Tocopherols have been purified from deodorizer distillate produced in the final deodorization step of vegetable oil refining
by a process including molecular distillation. Deodorizer distillate contains mainly tocopherols, sterols, and free fatty
acids (FFA); the presence of sterols hinders tocopherol purification in good yield. We found that Candida rugosa lipase recognized sterols as substrates but not tocopherols, and that esterification of sterols with FFA could be effected
with negligible influence of water content. Enzymatic esterification of sterols with FFA was thus used as a step in tocopherol
purification. High boiling point substances including steryl esters were removed from soybean oil deodorizer distillate by
distillation, and the resulting distillate (soybean oil deodorizer distillate tocopherol concentrate; SODDTC) was used as
a starting material for tocopherol purification. Several factors affecting esterification of sterols were investigated, and
the reaction conditions were determined as follows: A mixture of SODDTC and water (4∶1, w/w) was stirred at 35°C for 24 h
with 200 U of Candida lipase per 1 g of the reaction mixture. Under these conditions, approximately 80% of sterols was esterified, but tocopherols
were not esterified. After the reaction, tocopherols and FFA were recovered as a distillate by molecular distillation of the
oil layer. To enhance further removal of the remaining sterols, the lipase-catalyzed reaction was repeated on the distillate
under the same reaction conditions. As a result, more than 95% of the sterols was esterified in total. The resulting reaction
mixture was fractionated to four distillates and one residue. The main distillate fraction contained 65 wt% tocopherols with
low contents of FFA and sterols. In addition, the residue fraction contained high-purity steryl esters. Because the process
presented in this study includes only organic solvent-free enzymatic reaction and molecular distillation, it is feasible as
a new industrial purification method of tocopherols.
This work was presented at the Biocatalysis symposium in April 2000, held at the 91st Annual Meeting and Expo of the American
Oil Chemists Society, San Diego, CA. 相似文献
982.
Atsumi S. Umezawa A. Tanzawa T. Taura T. Shiga H. Takano Y. Miyaba T. Matsui M. Watanabe H. Isobe K. Kitamura S. Yamada S. Saito M. Mori S. Watanabe T. 《Solid-State Circuits, IEEE Journal of》2000,35(11):1648-1654
A 1.8-V-only 32-Mb NOR flash EEPROM has been developed based on the 0.25-μm triple-well double-metal CMOS process. A channel-erasing scheme has been implemented to realize a cell size of 0.49 μm2 , the smallest yet reported for 0.25-μm CMOS technology. A block decoder circuit with a novel erase-reset sequence has been designed for the channel-erasing operation. A bitline direct sensing scheme and a wordline boosted voltage pooling method have been developed to obtain high-speed reading operation at low voltage. An access time of 90 ns at 1.8 V has been realized 相似文献
983.
Kiyonami Takano Ken Nozaki Yoshiyasu Saito Akira Negishi Ken Kato Yoshio Yamaguchi 《Journal of power sources》2000,90(2):214-223
The electrical dynamic characteristics of a lithium-ion battery have been simulated by an equivalent circuit, which is derived from the measured impedance. The transient voltage response to the various kinds of applied current waves such as single pulse, single rectangular, triangle, and sawtooth waves is experimentally examined and calculated by using the numerical Laplace transform with the equivalent circuit. The experimental and calculated results are compared and discussed, focusing on the range of current where the linear relationship is valid. Changing the time range, the state of charge (SOC) and the battery temperature as parameters, their influence on the linear range of the applied current has been investigated. 相似文献
984.
Yoshio Maruyama Yoichiro Iwase Kazuo Koga Junichi Yagi Hiroo Takada Naohisa Sunaga Shigeomi Nishigaki Takashi Ito Kinya Tamaki 《Automation in Construction》2000,9(5-6):503-514
In this study, we proposed a concept of virtual and real-field construction management systems (VR-Coms), which is integrated with virtual construction simulation, planning, scheduling, and performance management systems to evaluate productivity and safety in virtual simulated and real-field constructions. And, we built up a computational environment to develop the VR-Coms. The VR-Coms offer supporting modules for learning and discovering solutions with objective to manage construction at right speed with improved humanware and constructability. The configuration of VR-Coms is described. This paper also shows an application of agent theory to construction management. 相似文献
985.
Ved P. Kafle Sangheon Pack Yanghee Choi Eiji Kamioka Shigeki Yamada 《Wireless Communications and Mobile Computing》2007,7(5):553-568
The advent of advanced mobile/wireless systems has been facilitating the battery‐powered mobile computing devices (nodes) to remain always connected to the internet. However, until now, the power‐drain rate of mobile nodes is very high in comparison with the available power of portable batteries. To reduce the energy consumption of mobile nodes, we present an integrated IP paging protocol (IIPP) by integrating the IP‐layer paging protocol based on Mobile IPv4 regional registration (MIPRR) with a power save mechanism. IIPP reduces the frequency of signaling messages between mobile nodes and networks. When not sending or receiving data for a certain time, mobile nodes enter power save mode (PSM), and consume very low power. We formulate analytical models and carry out simulations to evaluate the proposed IIPP. The results show that, compared to MIPRR, IIPP significantly reduces the average power consumption of the mobile node and signaling overheads in the network. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
986.
987.
Y. Yamada 《Engineering Fracture Mechanics》2009,76(2):209-220
Fatigue-crack-growth (FCG) rate tests were conducted on compact specimens made of an Inconel-718 alloy to study the behavior over a wide range in load ratios (0.1 ? R ? 0.95) and a constant Kmax test condition. Previous research had indicated that high R (>0.7) and constant Kmax test conditions near threshold conditions were suspected to be crack-closure-free and that any differences were attributed to Kmax effects. During a test at a load ratio of 0.7, strain gages were placed near and ahead of the crack tip to measure crack-opening loads from local load-strain records during crack growth. In addition, a back-face strain (BFS) gage was also used to monitor crack lengths and to measure crack-opening loads from remote load-strain records during the same test. The BFS gage indicated that the crack was fully open (no crack closure), but the local load-strain records indicated significant amounts of crack closure. The crack-opening loads were increasing as the crack approached threshold conditions at R = 0.7. Based on these measurements, crack-closure-free FCG data (ΔKeff against rate) were calculated. The ΔKeff-rate data fell at lower ΔK values and higher rates than the constant Kmax test results. In addition, constant R tests at extremely high R (0.9 and 0.95) were also performed and compared with the constant Kmax test results. The constant R test results at 0.95 agreed well with the ΔKeff-rate data, while the R = 0.9 data agreed well with constant Kmax test data in the low-rate regime. These results imply that the R = 0.7 test had a significant amount of crack closure as the threshold was approached, while the R = 0.9 and Kmax test results may have had a small amount of crack closure, and may not be closure free, as originally suspected. Under the high load-ratio conditions (R ? 0.7), it is suspected that the crack surfaces are developing debris-induced crack closure from contacting surfaces, which corresponded to darkening of the fatigue surfaces in the near-threshold regime. Tests at low R also showed darkening of the fatigue surfaces only in the near-threshold regime. These results suggest that the ΔKeff against rate relation may be nearly a unique function over a wide range of R in the threshold regime. 相似文献
988.
The specific heat, thermal diffusivity and thermal conductivity of porous SiC ceramics sintered using two kinds of SiC powders (fine and coarse) have been investigated for sintering temperatures in the range 1700–2000 °C. Sintered SiC has a porous structure with approximately 30–40 vol.% porosity. Thermal diffusivity was measured by the laser flash method. The thermal diffusivities and thermal conductivities of sintered SiC ceramics increased with increasing sintering temperature. The specific heat decreased slightly with increasing sintering temperature. The thermal diffusivities and thermal conductivities of SiC sintered from coarse powder were higher than those of SiC sintered from fine powder. The thermal conductivity of samples increased markedly with increasing grain size. 相似文献
989.
The magnetic anisotropy was studied as a function of the AlN layer thickness in [AlN(x nm)/CoPt(2 nm)]5/AlN(x nm) layered structure (x is AlN layer thickness, and 5 is the number of multilayer series). The multilayered film was deposited by a sputtering apparatus equipped with two pairs of facing targets. It was found that, in the range of AlN layer thickness below 30 nm, CoPt/AlN multilayers transform from an enhanced in-plane magnetic anisotropy to perpendicular magnetic anisotropy (PMA) through thermal annealing in vacuum, with an optimized AlN thickness of 10 nm for strong PMA. However, beyond this thickness range, the PMA did not occur, and thermal annealing only results in magnetic isotropy in both parallel and perpendicular directions. The related structure analysis revealed that smooth interface and good texture of CoPt (111) make positive contributions to interface anisotropy energy and magnetocrystalline anisotropy energy for producing PMA in CoPt/AlN layered structure. In addition, the transport phenomena were also studied by using a four-probe method. 相似文献
990.
Taro Inada Takeshi Kobayashi Noriyuki Sonoyama Atsuo Yamada Shigeo Kondo Miki Nagao Ryoji Kanno 《Journal of power sources》2009,194(2):1085-1088
All solid-state sheet lithium battery was developed using inorganic solid electrolyte, thio-LISICON (Li3.25Ge0.25P0.75S4), Li–Al anode, and Mo6S8 cathode materials, and the sheet manufacturing process was established. The new sheet-configuration was consisted of the cathode with the grid of current collector, electrolyte sheet with or without mechanical support, and aluminum/lithium composite sheet anode. A sheet battery with a dimension of 30 mm × 30 mm showed good charge–discharge characteristics without any capacity fading at a current of 0.1 mA. 相似文献