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排序方式: 共有71条查询结果,搜索用时 15 毫秒
1.
High performance liquid chromatographic separation of a series of mono-, di- and trihydroxylated 5β-cholanic acids which differ
only in position and configuration of hydroxyl groups at positions C-3, C-7 and/or C-12, is reported. The C-24 free acids
were derivatized to four different classes of UV-sensitive esters, i.e.,p-bromophenacyl (BP),m-methoxyphenacyl (MP), 4-nitrophthalimidemethyl (NPM) and 9-anthrylmethyl (AM) esters, and chromatographed on two, variants
of C18 reversed-phase columns (Nova-Pak C18 and Zorbax ODS) with methanol-water systems as mobile phase. Separation efficiency and elution order of some isomeric pairs
were influenced by both the structure of the C-24 ester groups and the nature of the columns used. Excellent chromatographic
properties were found for those derivatives, particularly for the NPM esters. 相似文献
2.
Toshinori Nakagawa Qinchang Zhu Hiroya Ishikawa Koichiro Ohnuki Kenichi Kakino Naoya Horiuchi 《木材化学与工艺学杂志》2016,36(1):42-55
This article presents multiple potential uses of the Yakushima native cedar (Cryptomeria japonica), known in Japan as the Yaku-sugi tree. The Yaku-sugi was divided into four parts: leaves, branches with leaves, branches, and stems. We obtained the essential oil, hydrosol, distillation residue, and distillation wastewater from the trees. Essential oil and hydrosol were determined to be volatile organic compounds. All samples were screened for the following bioactivities: antioxidative, antibacterial, and anti-melanogenesis activities. Freeze-dried distillation residue was tested to assess whether it had a deodorizing effect. The main component of the leaf essential oil was found to be monoterpenes. In contrast, the stem essential oil mainly contained sesquiterpenes. In terms of bioactivities, the leaf essential oil showed antibacterial activity and the stem essential oil showed anti-melanogenesis activity. Distillation residue and wastewater showed many activities, including antioxidant, antibacterial, and anti-melanogenesis activities. Moreover, the residue had a deodorizing effect against ammonia. 相似文献
3.
4.
A single oral administration of conjugated linoleic acid enhanced energy metabolism in mice 总被引:1,自引:0,他引:1
We investigated the effect of a single oral administration of conjugated linoleic acid (CLA) on energy metabolism in mice.
Male Std ddY mice were orally administered CLA (5 mL/kg weight) or linoleic acid (5 mL/kg weight) (both solutions at concentrations
of 73.5%) as a control. Oxygen consumption was significantly greater in the CLA-administered mice than in the control mice.
Respiratory quotient was slightly lower in the CLA-administered mice than in the control mice. We calculated fat and carbohydrate
oxidation from oxygen consumption and respiratory quotient. Fat oxidation in the CLA-administered mice was significantly higher
than in the control mice, and there was no difference in carbohydrate oxidation. Serum concentrations of noradrenalin and
adrenalin in the CLA administered mice were significantly higher than in the control mice. These results suggested that CLA
enhanced sympathetic nervous activity and energy metabolism. 相似文献
5.
Hao Yao Shigehito Isobe Yongming Wang Naoyuki Hashimoto Somei Ohnuki 《International Journal of Hydrogen Energy》2013
The thermal decomposition process of lithium alanate (LiAlH4) was investigated by TEM, TG-DTA and XRD. It was shown that LiAlH4 decomposes through a two-step reaction: a liquid-to-solid phase transition in the first step of the decomposition and a solid-to-solid reaction in the second step of the decomposition, both steps accompanied by hydrogen release. The particle size of the aluminum (Al), which formed in the first decomposition step, was much larger than that in the second decomposition step. In addition, Al particles formed in the liquid phase of LiAlH4 in the first decomposition step, while, they form in solid phase of Li3AlH6 in the second decomposition step, resulting in the kinetics of the first decomposition step being faster than that of the second decomposition step. The investigation clearly demonstrated the reaction model of the decomposition of LiAlH4 in the nano-scale, showing different diffusion processes of Al in each of the decomposition steps. 相似文献
6.
7.
Shigehito Isobe Somei OhnukiWilliam I.F. David Matthias GutmannMartin O. Jones Peter P. EdwardsTakayuki Ichikawa Yoshitsugu Kojima 《International Journal of Hydrogen Energy》2011,36(13):7909-7913
We have synthesized a single crystal of lithium amide (LiNH2, LiND2) by melting method, and performed neutron diffraction of the single crystal at variable temperature. LiND2 is tetragonal structure and I-4 space group. Lattice parameters and unit cell volume of LiND2 at room temperature, 50 °C, 100 °C, 150 °C and 200 °C were determined. Both of the lattice parameters and the unit cell volume increase with increase of temperature. From these results, we have estimated coefficient of volumetric thermal expansion αV of LiND2 to be 222 × 10−6/K. With increase of temperature, all thermal ellipsoids gradually expand because of thermal vibration. 相似文献
8.
Wei Liu Akira Ohnuki Hiroyuki Yoshida Masatoshi Kureta Kazuyuki Takase Hajime Akimoto 《传热工程》2013,34(8):704-711
A new reactor concept of innovative water reactor for flexible fuel cycle (FLWR) is under development at Japan Atomic Energy Agency in cooperation with Japanese reactor suppliers. A design of 1,356 MWe high conversion boiling water reactor-type FLWR core, which has an instantaneous conversion ratio of 1.04, negative void coefficient, high burnup of 65 GWd/t, and 15-month operational cycle length, has been constructed. So far, studies on thermal-hydraulic characteristics have been performed for tight lattice core. Evaluation methods for the critical power and the pressure drop under both the steady and the transient states have been established, and a modified TRAC-BF1 code has been developed for the thermal-hydraulic design of the FLWR. In this paper, the thermal feasibility of the designed 1356MWe FLWR core is analyzed by using the modified TRAC-BF1 code. The analysis is first carried out for the current core design. It is confirmed that no boiling transition (BT) occurs under the steady state. However, the minimum critical power ratio (MCPR) is only about 1.08, and the BT is confirmed occurring under the postulated abnormal transient processes. Therefore, concretizations of the conditions that ensure the thermal feasibility of a natural circulation-type FLWR and a forced circulation-type FLWR are performed. As for the results, for a forced circulation-type FLWR, the operation-limited MCPR (OLMCPR) is 1.32, and the necessary minimum core coolant flow rate is 640 kg/(m2s). For a natural circulation-type FLWR, the OLMCPR is 1.19, and the necessary minimum core coolant flow rate is 560 kg/(m2s). 相似文献
9.
Right facial nerve palsy in a 58-year-old woman was due to sarcoidosis demonstrated by Gd-DTPA enhanced MRI. Abnormal enhancement of the right VIIth cranial nerve in the distal internal acoustic canal was seen on MRI. The enhancing lesion was smaller after 1 month of prednisolone 50 mg day-1. This is the first report on facial nerve involvement in neurosarcoidosis examined by Gd-DTPA enhanced MRI. The use of Gd-DTPA enhanced MRI with thin slicing, e.g. 3 mm slice thickness and 1 mm interslice gap, is effective in detecting small extramedullary lesions. 相似文献
10.
Numerical accuracy of multipole expansion for 2D MLFMA 总被引:2,自引:0,他引:2
A numerical study of the multipole expansion for the multilevel fast multipole algorithm (MLFMA) is presented. In the numerical implementation of MLFMA, the error comes from three sources: the truncation of the addition theorem; the approximation of the integration; the aggregation and disaggregation process. These errors are due to the factorization of the Green's function which is the mathematical core of the algorithm. Among the three error sources, we focus on the truncation error and a new approach of selecting truncation numbers for the addition theorem is proposed. Using this approach, the error prediction and control can be improved for the small buffer sizes and high accuracy requirements. 相似文献