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排序方式: 共有197条查询结果,搜索用时 390 毫秒
151.
Jun Sakakibara 《Experiments in fluids》2013,54(12):1-16
Evolution of the near-field structures of a plane jet excited by temporal periodic disturbances with spanwise phase variations was investigated with stereoscopic particle image velocimetry. The three-dimensional vorticity distributions were reconstructed by using Taylor’s frozen field hypothesis. When ?, the temporal phase difference of disturbances in the spanwise direction was π; chain-link-fence type structures were formed. The $\Uplambda$ vortices in the chain-link-fence structures were then distorted into an $\Upomega$ shape, and the head of the vortex was detached and reconnects to form a vortex ring, or reconnects to the adjacent V-shaped vortices to form an A-shaped vortex. After the reconnection stage, the flow field was occupied by uniformly distributed fine scale eddies. Here, the overall turbulent kinetic energy and shear stress were suppressed, and the jet width was narrower than that of the unexcited case and other forced cases. In the case of ? = π/2, spanwise rollers and rib structures were formed near the nozzle exit after the first vortex pairing. However, further vortex pairing did not occur downstream, and the rate at which the jet widened was reduced. 相似文献
152.
Hiroki Matsuzaka Hiroki Matsuyama Wataru Tanaka Hayato Tajiri Hiroyuki Sakakibara 《Molecules (Basel, Switzerland)》2022,27(4)
Diets with high daily fat consumption are associated with excess weight. However, the effects of fat type and consumption timing on excess weight remain unclear. We investigated the selection of a 30% (w/w) fat diet of soybean oil (SOY), lard (LARD), and fish oil (FISH) on the metabolic parameters of mice. Male C57BL/6 mice were divided into the double SOY-box (w-SOY), SOY-box/LARD-box (SOY-vs-LARD), or SOY-box/FISH-box (SOY-vs-FISH) groups and allowed to selectively consume for 8 weeks. The total energy intake was similar for all groups, but the mice selectively chose to consume LARD over SOY and SOY over FISH. Body weight in the SOY-vs-LARD group was significantly higher than that in the w-SOY and SOY-vs-FISH groups. Additionally, minimal but selective consumption of an omega-3 fatty-acid-rich FISH diet at the end of the active period increased the physiological fatty acid compositions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the SOY-vs-FISH group; their metabolic parameters were also lower than the SOY-vs-LARD group. In conclusion, selectively consuming small amounts of fish oil at the end of the day may prevent excess weight compared with LARD consumption. 相似文献
153.
Toi K Watanabe F Tokuzawa T Ida K Morita S Ido T Shimizu A Isobe M Ogawa K Spong DA Todo Y Watari T Ohdachi S Sakakibara S Yamamoto S Inagaki S Narihara K Osakabe M Nagaoka K Narushima Y Watanabe KY Funaba H Goto M Ikeda K Ito T Kaneko O Kubo S Murakami S Minami T Miyazawa J Nagayama Y Nishiura M Oka Y Sakamoto R Shimozuma T Takeiri Y Tanaka K Tsumori K Yamada I Yoshinuma M Kawahata K Komori A;LHD Experiment Group 《Physical review letters》2010,105(14):145003
Reversed-shear Alfvén eigenmodes were observed for the first time in a helical plasma having negative q?' (the curvature of the safety factor q at the zero shear layer). The frequency is swept downward and upward sequentially via the time variation in the maximum of q. The eigenmodes calculated by ideal MHD theory are consistent with the experimental data. The frequency sweeping is mainly determined by the effects of energetic ions and the bulk pressure gradient. Coupling of reversed-shear Alfvén eigenmodes with energetic ion driven geodesic acoustic modes generates a multitude of frequency-sweeping modes. 相似文献
154.
155.
156.
Optical Review - Diffuse optical imaging has been applied to measure the localized hemodynamic responses to brain activation. One of the serious problems with diffuse optical imaging is the... 相似文献
157.
Oligosaccharyl Fmoc-asparagine in which amide nitrogen of the asparagine side chain attached to the anomeric position at the reducing end, is a versatile building block and has been used for various glycopeptide synthesis using Fmoc solid-phase peptide synthesis (SPPS). We found unexpected aspartimide formation between amide nitrogen at the reducing end and α-carboxyl acid of oligosaccharyl Fmoc-asparagine during activation of α-carboxyl acid and this side reaction resulted in low coupling yields of oligosaccharyl Fmoc-asparagine with peptide-resin. This aspartimide formed efficiently using conventional coupling reagents such as PyBOP and HATU, but DEPBT afforded little of the aspartimide derivative. Activation condition using DEPBT (3.0 equiv) and DIPEA (2.0 equiv) afforded excellent yield (97%) in coupling reaction between Fmoc-Asn(CHO)-OH and peptide-resin. Based on these results, we performed a synthesis of a sialylglycopeptide, HIV-gp120 (54-63) VVLLVN(CHO)VTENF, in high yield. 相似文献
158.
An abelian *-semigroup S is perfect (resp. Stieltjes perfect) if every positive definite (resp. completely so) function on S admits a unique disintegration as an integral of hermitian multiplicative functions (resp. nonnegative such). We prove that
every Stieltjes perfect semigroup is perfect. The converse has been known for semigroups with neutral element, but is here
shown to be not true in general. We prove that an abelian *-semigroup S is perfect if for each s ∈ S there exist t ∈ S and m, n ∈ ℕ0 such that m + n ≥ 2 and s + s* = s* + mt + nt*. This was known only with s = mt + nt* instead. The equality cannot be replaced by s + s* + s = s + s* + mt + nt* in general, but for semigroups with neutral element it can be replaced by s + p(s + s*) = p(s + s*) + mt + nt* for arbitrary p ∈ ℕ (allowed to depend on s). 相似文献
159.
Tetsuya Doi Takumi Sakakibara Dr. Hiromu Kashida Dr. Yasuyuki Araki Prof. Dr. Takehiko Wada Prof. Dr. Hiroyuki Asanuma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(45):15974-15980
We report on the characterization of a novel hetero‐selective DNA‐like duplex of pyrene and anthraquinone pseudo base pairs. The pyrene/anthraquinone pairs showed excellent selectivity in hetero‐recognition and even trimers were found to form a hetero‐duplex. Pyrene and anthraquinone moieties were tethered on acyclic D ‐threoninol linkers and linked to adjacent residues by using standard phosphoramidite chemistry. When pyrene and anthraquinone were incorporated at pairing positions in complementary strands of natural DNA oligonucleotides, the duplex was stabilized significantly. Moreover, a pyrene hexamer and an anthraquinone hexamer formed a stable artificial hetero‐duplex without the assistance of natural base pairs. The pyrene/anthraquinone pair was so stable that even trimers formed a hetero‐duplex under conditions in which natural DNA strands of three residues do not. 相似文献
160.
Koya Sakakibara 《Applications of Mathematics》2017,62(4):297-317
The aim of this paper is to analyze mathematically the method of fundamental solutions applied to the biharmonic problem. The key idea is to use Almansi-type decomposition of biharmonic functions, which enables us to represent the biharmonic function in terms of two harmonic functions. Based on this decomposition, we prove that an approximate solution exists uniquely and that the approximation error decays exponentially with respect to the number of the singular points. We finally present results of numerical experiments, which verify the sharpness of our error estimate. 相似文献