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The flapping flight of tiny insects such as flies or larger insects such as butterflies is of fundamental interest not only in biology itself but also in its practical use for the development of micro air vehicles (MAVs). It is known that a butterfly flaps downward for generating the lift force and backward for generating the thrust force. In this study, we consider a simple butterfly-like flapping wing–body model in which the body is a thin rod and the rectangular rigid wings flap in a simple motion. We investigate lift and thrust generation of the model by using the immersed boundary–lattice Boltzmann method. First, we compute the lift and thrust forces when the body of the model is fixed for Reynolds numbers in the range of 50–1000. In addition, we estimate the supportable mass for each Reynolds number from the computed lift force. Second, we simulate free flights when the body can only move translationally. It is found that the expected supportable mass can be supported even in the free flight except when the mass of the body relative to the mass of the fluid is too small, and the wing–body model with the mass of actual insects can go upward against the gravity. Finally, we simulate free flights when the body can move translationally and rotationally. It is found that the body has a large pitch motion and consequently gets off-balance. Then, we discuss a way to control the pitching angle by flexing the body of the wing–body model.
We conducted a double-blind, placebo-controlled trial to evaluate the effect of heat-killed cells of Lactococcus lactis strain H61 on various skin properties of Japanese women. Volunteers (age 31–62 years) were randomly assigned to receive test food with or without 60 mg of heat-killed strain H61 (fifteen women in each group; H61 and control groups, respectively) daily for 8 weeks. Results were analysed for three age categories (30s, 40s and 50–60s). Compared with that at week 0, skin hydration at the inner forearm at weeks 4 and 8 decreased in all volunteers (except those in their 50–60s) because of the environmental change from autumn to winter. The oldest H61 group maintained skin hydration at the inner forearm throughout the study. Skin elasticity and melanin content in the cheek decreased and sebum content increased throughout the test period due to seasonal environmental change, regardless of age or H61 treatment. Self-evaluation scores for apparent hair follicles and dryness of the throat at week 8 were higher in the overall H61 group than in the combined placebo group. The 30s H61 group noted marked improvements in self-surveyed skin elasticity at week 8 compared with at week 0 and with the placebo group at week 8. The results of the present study indicate that oral intake of heat-killed cells of L. lactis strain H61 can improve some skin properties and body characteristics in women. This strain would probably be useful in increasing the quality of life in an ageing population.
In this study, the dense films of well-crystallized ZnO nanocrystals were successfully prepared by direct spin-coating of the colloidal solution of ZnO nanoparticles derived from the microemulsion method. The average grain sizes in the films were reasonably controlled in the range from 6.5 to 34.3 nm by simply changing the annealing temperatures. The increase in band gap energies was found in the size region less than 13.3 nm, finally resulting in 3.47 eV for the average size of 6.5 nm. The photoluminescence spectra at room temperature showed intense ultraviolet (UV) emission with faint green luminescence. The Stokes shifts of the films were estimated to be one or two orders of magnitude smaller than those of the conventional ZnO nanocrystalline films, suggesting the well crystallization and slight amounts of lattice defects in the ZnO nanoparticles. These excellent features may be favorable to make high-performance optical application such as UV emitting devices.
The electrospray of a colloidal microemulsion (ME) solution and subsequent on-line annealing were used to produce barium titanate nanoparticles (BTO-NPs). The solvent of the ME solution (cyclohexane) was replaced with a high-conductivity solution (solute: ammonium acetate, solvent: tetrahydrofurfuryl alcohol, conductivity: 3.1 × 10−2 S/m) to generate ultrafine droplets during the electrospraying. Well-dispersed and well-crystallized BTO-NPs with a perovskite structure were successfully fabricated at an annealing temperature of 1173 K. The size distribution of the BTO-NPs was successfully measured by applying a differential mobility analyzer and condensation nucleation counter to nanoparticles in-flight. The average size of the BTO-NPs was controlled within a range of 15 to 25 nm by changing the feeding rate. The electrospray of an ME solution with lower conductivity (solvent: 1-octanol, conductivity: 7.0 × 10−4 S/m) yielded amorphous particles with larger particle sizes. Thus, the electrospray of a high-conductivity solution is required to fabricate well-crystallized and dense BTO-NPs with smaller particle sizes.
The effects of oral administration of a lactococcal strain on physiological changes associated with ageing were investigated using senescence-accelerated mice (SAM). SAM develop normally, but then show an early onset and irreversible advancement of senescence. SAMP6 is a SAM strain that develops osteoporosis with ageing. Oral administration of heat-killed Lactococcus lactis subsp. cremoris H61 (strain H61) to aged SAMP6 mice was associated with reduced bone density loss, a suppression of incidence of skin ulcers and reduced hair loss, compared with controls. Spleen cells from mice fed strain H61 produced more interferon-γ and IL-12 than those from control mice, suggesting that administration of strain H61 altered immune responses. The numbers of viable cells of Bifidobacterium sp., Bacteroides sp. and Enterococcus sp. in faeces were similar for mice fed the strain H61 and control diets, but counts for Staphylococcus sp. were significantly lower (P < 0·05) in mice fed strain H61. Mice fed strain H61 had similar serum concentrations of thiobarbituric acid-reactive substances as in controls, indicating a lack of effect on lipid peroxidation status. Administration of living cells of strain H61 or fermented milk containing strain H61 was also associated with a suppression of incidence of skin ulcers and reduced hair loss. These results indicate that oral administration of strain H61 has the potential to suppress some of the manifestations associated with ageing.
The striped nano-channel structure (about 10nm in depth) was formed on the NiO film surface by thermal annealing of the film deposited on the sapphire(0001) substrate with periodic straight atomic steps. The interval of each nano-channel was about 100nm in average and well corresponding to the separation of atomic steps on the used sapphire(0001) substrate. Effects of annealing temperature and impurity doping into NiO upon the nanochannel formation were examined in order to control the depth. The depth of nano-channels formed on the alkali-metal(Li or Na) doped NiO films were found to be larger than that of nano-channels on the non-doped NiO films and enlarged with increasing annealing temperature in the range of 500∼900°C. Atomic-scale cross sectional structure of the nano-channel was characterized by transmission electron microscopy with focused on the film/substrate interface.
Cubic GaN is successfully grown on β-Ga2O3 by molecular beam epitaxy for the first time. Prior nitridation of the (100) β-Ga2O3 single-crystal substrate by exposure to electron cyclotron resonance nitrogen plasma causes the formation of a surficial (001) c-GaN layer, upon which homo-epitaxial growth of c-GaN can be achieved by radio-frequency molecular beam epitaxy. The epitaxial relationship is confirmed by electron microscopy to be (001) c-GaN // (100) β-Ga2O3,  c-GaN //  β-Ga2O3, and [1-10] c-GaN //  β-Ga2O3.
Polycrystalline alkaline-earth hexaborides (MB6: M =Ca, Sr, Ba) were synthesized and their thermoelectric and transport properties were examined to discuss their possibility as high temperature thermoelectric materials. Hall measurements showed that carrier concentration of the BaB6 was the highest among the three hexaborides and that of CaB6 was the lowest. Substitution of part of the alkaline earth metals with one of the others changed the carrier concentration of the hexaboride. As the carrier concentration increased, Seebeck coefficient increased and electrical conductivity decreased. These results suggest that the thermoelectric properties of the divalent hexaborides depend largely on the carrier concentration, and optimum carrier concentration which gives maximum power factor was estimated to be approximately 2x1026 m−3. Consequently, such a substitution enables us to control Seebeck coefficient and electrical conductivity of the hexaborides, and will also be effective to reduce the lattice heat conduction due to the alloying effect. A thermoelectric device was fabricated using SrB6 and boron carbide thin films as n-type and p-type elements, respectively. To the best of our knowledge, this is the first demonstration of a thermoelectric device composed of only boron-rich solids.
a-/b-axis-oriented epitaxial bismuth layer-structured ferroelectric thin films were epitaxially grown on (101)-oriented oxide with rutile structure. The long-range lattice matching between the ferroelectric layer and the bottom rutile layer, particularly the number of rutile units facing one ferroelectric unit and the surface orientation, were discussed for (100)(010)Bi4Ti3O12//(101)TiO2 structure. Cross sectional transmission electron microscope analysis suggests that seven rutile units lie under one a-/b-axis-oriented Bi4Ti3O12 unit with lower misfit dislocation density comparing to eight rutile units by one Bi4Ti3O12 model. Based on this result, the surface orientation at the interface was simulated to give us an appropriate ion alignment model. The titanium layer in the (101)TiO2 structure is most likely to match with the oxygen layer in the a-/b-axis-oriented Bi4Ti3O12 film.
To determine annual layers for reconstructing the past environment at annual resolution from ice cores, we employed snow-stake data back to 1972, tritium content, solid electrical conductivity measurements (ECM) and stratigraphic properties for the 73m ice core at the H72 site, east Dronning Maud Land, Antarctica. the average annual surface mass balance at H72 is 307 mma–1w.e. during the last 27 years from continuous accumulation data, 317 mma–1 w.e. according to the densification model and 311 mma–1 w.e. according to the average surface mass balance for 167 years based on annual-layer counting. the ECM age is closely coincident with tritium age, and corresponds with the snow-stake record back to AD 1972 from the surface to 15 m depth. the H72 ice core is dated as AD 1831by ECMat 73.16 mdepth.The time series of yearly surface mass balance at H72 shows an almost constant 311 mm a–1 w.e. for the last 167 years. the oxygen-isotope records indicate a significant trend to lower values, with negative gradient of 1.7% (100 years)–1.
Epitaxial (001)-, (116)- and pseudo (103)-oriented Sr0.35Bi2.2Ta2O9 (SBT (0.35/2.2/2.0)) films were successfully grown on (001), (110) and (111) SrTiO3 substrates, respectively. High-resolution X-ray diffraction reciprocal space mapping (HRXRD-RSM) measurements and pole figure measurements clearly indicated that the (116)-oriented SBT (0.35/2.2/2.0) film consisted of two growth domains those c-axis are separated 180° apart in in-plane and pseudo (103)-oriented SBT film consisted of three growth domains those c-axis are separated 120° apart in in-plane. Moreover, lattice parameter measurements indicated that SBT films grew in fully relaxed state.
X-ray fractography is a new method utilizing the X-ray diffraction technique to observe the fracture surface for the analysis of the micro-mechanisms and mechanics of fracture.
In the present paper, X-ray fractography is applied to fracture surfaces of high strength aluminum alloy (JIS 7075-T6). The fracture toughness tests were conducted by using compact tension (CT) specimens with blunt notches and fatigue pre-cracks. The distribution of the residual stress near fracture surfaces was measured by the X-ray diffraction method. The effect of the notch radius on the fracture toughness value was discussed.
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