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Effective Symmetry Breaking of Flow in AC Electro-Osmotic Pump Using a Ratchet Structure
No full textAC electro-osmotic (ACEO) pumps play an important role in a wide diversity of microfiuidic applications. To produce high flow velocities, an effective breaking of symmetry is prerequisite. Here, we introduced a ratchet-structured electrode for achieving high flow velocities and developed a ratchet ACED pump containing both ratchet and plane electrodes. The performance of our new ACED pump is evaluated experimentally. At an ac voltage of 30 V at 10kHz, a maximum net flow velocity of 1.1 mm/s is measured along the inclined direction of the ratchet teeth. Furthermore, we also directly observed the flow fields due to the slip velocity of ACEO, which provide a physical insight on the ratchet-type ACED pumps.ArticleJOURNAL OF THE PHYSICAL SOCIETY OF JAPAN.88(8):084602(2019)journal articl
Connected correlator of 1/2 BPS Wilson loops in N=4 SYM
No full textWe study the connected correlator of 1/2 BPS winding Wilson loops in N = 4 U(N) super Yang-Mills theory, where those Wilson loops are on top of each other along the same circle. We find the exact finite N expression of the connected correlator of such Wilson loops. We show that the 1/N expansion of this exact result is reproduced from the topological recursion of Gaussian matrix model. We also study the exact finite N expression of the generating function of 1/2 BPS Wilson loops in the symmetric representation.ArticleJOURNAL OF HIGH ENERGY PHYSICS.(10):37(2018)journal articl
Wilson loops in unitary matrix models at finite N
No full textIt is known that the expectation value of Wilson loops in the Gross-Witten-Wadia (GWW) unitary matrix model can be computed exactly at finite N for arbitrary representations. We study the perturbative and non-perturbative corrections of Wilson loops in the 1/N expansion, either analytically or numerically using the exact result at finite N. As a by-product of the exact result of Wilson loops, we propose a large N master field of GWW model. This master field has an interesting eigenvalue distribution. We also study the Wilson loops in large representations, called Giant Wilson loops, and comment on the Hagedorn/deconfinement transition of a unitary matrix model with a double trace interaction.ArticleJOURNAL OF HIGH ENERGY PHYSICS.(7):30(2017)journal articl
Instanton corrections of 1/6 BPS Wilson loops in ABJM theory
No full textWe study instanton corrections to the vacuum expectation value (VEV) of 1/6 BPS Wilson loops in ABJM theory from the Fermi gas approach. We mainly consider Wilson loops in the fundamental representation and winding Wilson loops, but we also initiate the study of Wilson loops with two boundaries. We find that the membrane instanton corrections to the Wilson loop VEV are determined by the refined topological string in the Nekrasov-Shatashvili limit, and the pole cancellation mechanism between membrane instantons and worldsheet instantons works also in the Wilson loop VEVs as in the case of the partition functions.ArticleJOURNAL OF HIGH ENERGY PHYSICS.(9):125(2016)journal articl
Stellar Stratifications on Classifying Spaces
No full textBook chapterAlgebraic Topology and Related Topics: 287-313(2019)boo
Aerodynamic comparison of a butterfly-like flapping wing-body model and a revolving-wing model
No full textThe aerodynamic performance of flapping- and revolving-wing models is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. As wing models, we use (i) a butterfly-like model with a body and flapping- rectangular wings and (ii) a revolving-wing model with the same wings as the flapping case. Firstly, we calculate aerodynamic performance factors such as the lift force, the power, and the power loading of the two models for Reynolds numbers in the range of 50-1000. For the flapping-wing model, the power loading is maximal for the maximum angle of attack of 90 degrees, a flapping amplitude of roughly 45 degrees, and a phase shift between the flapping angle and the angle of attack of roughly 90 degrees. For the revolving-wing model, the power loading peaks for an angle of attack of roughly 45 degrees. In addition, we examine the ground effect on the aerodynamic performance of the revolving-wing model. Secondly, we compare the aerodynamic performance of the flapping- and revolving-wing models at their respective maximal power loadings. It is found that the revolving-wing model is more efficient than the flapping- wing model both when the body of the latter is fixed and where it can move freely. Finally, we discuss the relative agilities of the flapping- and revolving-wing models.ArticleFLUID DYNAMICS RESEARCH.49(3):035512(2017)journal articl
Apolipoprotein A-II induces acute-phase response associated AA amyloidosis in mice through conformational changes of plasma lipoprotein structure
No full textDuring acute-phase response (APR), there is a dramatic increase in serum amyloid A (SAA) in plasma high density lipoproteins (HDL). Elevated SAA leads to reactive AA amyloidosis in animals and humans. Herein, we employed apolipoprotein A-II (ApoA-II) deficient (Apoa2(-/-)) and transgenic (Apoa2Tg) mice to investigate the potential roles of ApoA-II in lipoprotein particle formation and progression of AA amyloidosis during APR. AA amyloid deposition was suppressed in Apoa2(-/-) mice compared with wild type (WT) mice. During APR, Apoa2(-/-) mice exhibited significant suppression of serum SAA levels and hepatic Saa1 and Saa2 mRNA levels. Pathological investigation showed Apoa2(-/-) mice had less tissue damage and less inflammatory cell infiltration during APR. Total lipoproteins were markedly decreased in Apoa2(-/-) mice, while the ratio of HDL to low density lipoprotein (LDL) was also decreased. Both WT and Apoa2(-/-) mice showed increases in LDL and very large HDL during APR. SAA was distributed more widely in lipoprotein particles ranging from chylomicrons to very small HDL in Apoa2(-/-) mice. Our observations uncovered the critical roles of ApoA-II in inflammation, serum lipoprotein stability and AA amyloidosis morbidity, and prompt consideration of therapies for AA and other amyloidoses, whose precursor proteins are associated with circulating HDL particles.ArticleSCIENTIFIC REPORTS.8:5620(2018)journal articl
Effect of melt spinning conditions on the fiber structure development of polyethylene terephthalate
No full textThe effects of spinning conditions on fiber properties are not well explained by the fiber structures because the birefringence, crystallinity, and SAXS patterns are often similar. In this study, the effects on the fiber structure development of polyethylene terephthalate after necking was analyzed by simultaneous WAXD/SAXS measurements. An X-shaped SAXS pattern was observed for all fibers drawn at the minimum draw ratio. In contrast, by drawing under a drawing stress of 100 MPa, the strong diffraction of the smectic phase and an obviously larger long period less than 1 ms after necking were observed for fibers spun at 500-1500 m/min, while almost no smectic phase was observed for fibers spun at 2000 m/min. A higher crystallization rate and clear draw ratio dependence of crystallization rate were also observed for the fiber spun at 2000 m/min. The clear differences in structure development can explain their differences in tensile strength and thermal shrinkage. (C) 2017 Elsevier Ltd. All rights reserved.ArticlePOLYMER.116:367-377(2017)journal articl