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The geometry of compound sessile drops at equilibrium on a flat substrate can exhibit a variety of complicated morphological configurations. In this paper, we first investigate the configuration boundaries of the compound sessile drops in a wide parameter space, where a specific configuration is not stable outside its boundaries. Then, we focus on the transitions among the axisymmetric configurations, i.e. encapsulation, lens and collars. The configuration transitions result from the variation of the wettability of the substrate and the volume ratio of the two component droplets. With the help of theoretical analysis and numerical simulations, we obtain previously unidentified criteria for the onset of configuration transition, identify the irreversible and reversible configuration transitions, reveal the dynamic behaviours of configuration transitions that are not accessible to theoretical analysis, and provide a further step towards the ultimate purpose of such work, which is the controllable reconfiguration of the compound sessile drops.
A supercapacitor electrode featured with a voltage self-stabilizing capability is demonstrated by growing indium tin oxide (ITO) nanowires on Ni foam. The ITO nanowires with a single crystal structure are prepared by using magnetron sputtering technique, and they can act as an active electrode material. Charging–discharging experiments are performed under different current densities, demonstrating a good rate capability. Using properly designing top and bottom double connection circuits, part of the electrode can be used as a resistance switch. An electrode that can function as a supercapacitor and a resistance switch is fabricated. Detailed characteristics confirm that the device not only exhibits high performance as a supercapacitor but also has good characteristics of resistance switching (RS). The specific capacitance is 956 F/g at the scanning rate of 10 mV/s, and the switching ratio as a bipolar resistance switch is as high as 102. The stabilization time of discharging voltage is nearly doubled longer than that without any RS function, revealing the potential application of our devices, which can be used as a supercapacitor with voltage self-stabilizing.
We report on environmentally stable long-cavity ultrashort erbium-doped fiber lasers, which self-start mode-locking at quite low thresholds by using spectrally filtered and phase-biased nonlinear amplifying long-loop mirrors. By employing 100-m polarization-maintaining fiber (PMF) in the nonlinear loop, the fundamental repetition rate reaches 1.84 MHz and no practical limitation is found to further decrease the repetition rate. The filter used in the long loop not only suppresses Kelly sidebands of the solitons, but also eliminates the amplified spontaneous emission which exists widely in low-repetition-rate ultrafast fiber lasers. The bandwidth of the filter is optimized by using a numerical model. The laser emits approximately 3-ps pulses with an energy of 17.4 pJ, which is further boosted to
by using a fiber amplifier.
Multi-pass warm rolling with falling temperature was proposed and investigated to obtain AZ31 Mg alloy sheets with a fine-grained microstructure. The results indicated that the grain microstructure of AZ31 alloy sheets was successfully refined from 22.1 to 4.5 μm after multi-pass warm rolling with falling temperature and annealing. Compared to the as-received sheet, the multi-pass warm rolled sheets in annealed condition exhibited weaker (0001) basal texture intensity, which resulted in the significantly increased Schmid factor of 〈a〉 basal slip. After multi-pass warm rolling with falling temperature, the rolled sheets in annealed condition also exhibited much better mechanical properties, e.g., higher tensile strength, larger fracture elongation, and higher Erichsen value, especially the IE of 8-pass warm rolled sheet in annealed condition was significantly increased by ∼33% under the same thickness, which could be attributed to the refined grain microstructure and the weakened basal texture.
Auto-alignment is a basic technique for high-power laser systems. Special techniques have been developed for laser systems because of their differing structures. This paper describes a new sensor for auto-alignment in a laser system, which can also serve as a reference in certain applications. The authors prove that all of the beam transfer information (position and pointing) can theoretically be monitored and recorded by the sensor. Furthermore, auto-alignment with a single lens sensor is demonstrated on a simple beam line, and the results indicate that effective auto-alignment is achieved.
Shot-peened CM400 maraging steel was used to study the mechanism of enhanced notch fatigue properties of ultra-high strength materials. After shot peening, the specimen surface became rougher, but the transversal machining traces were reduced. The yield strength was slightly improved while the ultimate tensile strength and hardness maintained constant; as a result, the fatigue limit was promoted by about 1.5 times. The nucleated sites of the fatigue fracture were partly changed from the surface to subsurface/interior of the specimen. To further analyze the influencing factors of fatigue properties, the fatigue damage process may be resolved to two aspects: (a) fatigue damage rate affected by shear deformation and (b) fatigue damage tolerance controlled by the dilatation fracture process. Considering the stress state near the notch tip, the hydrostatic stress and maximum shear stress are considered for better understanding these two aspects. It is observed that the fatigue damage tolerance increased while the fatigue damage rate decreased after shot peening. Therefore, the notch fatigue properties of CM400 maraging steels can effectively be improved.
This investigation addresses the dynamics of annular viscoelastic films flowing down a flexible tube. The fluid viscoelasticity is assumed to be weak in order to obtain approximate explicit expressions for the stresses. Based on Shkadov’s integral boundary layer method (Fluid Dyn., vol. 2(1), 1967, pp. 29–34), a set of nonlinear evolution equations is derived that is valid for flows with moderate Reynolds numbers. The linear stability property of the system is examined by using normal-mode analysis, which is verified by comparing the results with those resulting from the linearization of the full Navier–Stokes equations. The results indicate that the fluid viscoelasticity plays an unstable role in the stability of the annular film flow. The tube flexibility, which includes wall damping and wall tension, plays a dual role. A bifurcation analysis is performed, and the families of steady travelling waves are catalogued. It is found that the stiffness of the tube tends to stimulate the interfacial capillary ripples. The fluid viscoelasticity acts to strengthen the dispersion of the interfacial waves but weakens the interfacial capillary ripples. The spatio-temporal evolutions of the system are also solved numerically. When the tube radius is small enough, tube closure can be observed due to the Plateau–Rayleigh instability. The fluid viscoelasticity acts to promote tube closure while the tube radius is relatively small. However, it plays a role in postponing the closure of the tube with a large radius.
Fatty acids (FA) are a non-protein energy source and can act as trophic biomarkers in benthic food webs. We analysed the FA profiles of sea cucumber Apostichopus japonicus, comparing tissues of body wall, gut sediment and ovaries in two habitats. Rongcheng Bay: kelp raft cultivation area with high organic matter in sediment; Laoshan Bay: strong current with low sediment organic matter. The results showed that body wall and ovary tissues were rich in long chain polyunsaturated FA (LC-PUFA), which contributed ~31% to the FA dissimilarity between the two tissues. SIMPER (similarity percentages routine) results showed that C20:5ω3 (EPA), C18:1ω7, C20:4ω6 (AA), C16:0, C14:1 and C20:1ω11 contributed to dissimilarity between the body wall and ovary tissues, while 16:1ω7, 20:5ω3, C16:0, C18:1ω7, C18:0 and C14:1 contributed more to the dissimilarity of body wall tissues between the two habitats. FA biomarkers showed that sea cucumbers from the two habitats had different food sources, with brown kelp and vascular plants being the main food for sea cucumbers in Rongcheng and diatoms for those in Laoshan. To better understand differences in FA composition in sea cucumbers, more research is needed examining a wider diversity of tissue types and habitats.
We studied the tank treading motion of an erythrocyte (red blood cell, or RBC) in linear shear flows by using a boundary-element fluid-dynamics model coupled with a multiscale structural model of the cell. The purpose was to investigate the correlation between the reference (stress-free) state of the cytoskeleton and the cell dynamics in shear flows with relatively high capillary numbers. We discovered that there exist two distinctive modes of tank treading, mode 1 and mode 2. In mode 1 the membrane elements originating from the dimple areas keep close to the central plane, whereas in mode 2 these elements remain near the farthermost locations from the central plane. Mode 1 is also characterized by significantly higher breathing and swinging oscillations. During tank treading one mode may become unstable and switch to the other. Their stability depends on the viscosity ratio and the capillary number. At a fixed viscosity ratio, when the capillary number is increased the cell experiences sequentially a region dominated by mode 2, a mode 1/mode 2 bistable region and a region dominated by mode 1. More profoundly, these regions are highly sensitive to the reference state of the cytoskeleton. For example, compared with a cell with a biconcave reference state, a cell with a spheroidal reference state features a much smaller region dominated by mode 2. This finding may guide experiments to identify the actual reference state of these cells.
Considerable controversy exists regarding the associations of dietary patterns with the risk of all-cause, CVD and stroke mortality. Therefore, a meta-analysis was conducted to elucidate the potential associations between dietary patterns and the risk of all-cause, CVD and stroke mortality. The PubMed database was searched for prospective cohort studies on the associations between dietary patterns and the risk of all-cause, CVD and stroke mortality published until February 2014. Random-effects models were used to calculate the summary relative risk estimates (SRRE) based on the highest v. the lowest category of dietary pattern scores. Stratified analyses were conducted based on sex, geographical region, follow-up duration, and adjustment/non-adjustment for energy intake. A total of thirteen prospective cohort studies involving 338 787 participants were included in the meta-analysis. There was evidence of inverse associations between the prudent/healthy dietary pattern and the risk of all-cause (SRRE = 0·76, 95 % CI 0·68, 0·86) and CVD (SRRE = 0·81, 95 % CI 0·75, 0·87) mortality and an absence of association between this dietary pattern and stroke mortality (SRRE = 0·89, 95 % CI 0·77, 1·02). However, no significant associations were observed between the Western/unhealthy dietary pattern and the risk of all-cause (SRRE = 1·07, 95 % CI 0·96, 1·20), CVD (SRRE = 0·99, 95 % CI 0·91, 1·08) and stroke (SRRE = 0·94, 95 % CI 0·81, 1·10) mortality. In conclusion, the findings provide evidence that greater adherence to a prudent/healthy dietary pattern is associated with a lower risk of all-cause and CVD mortality and not significantly associated with stroke mortality and that the Western/unhealthy dietary pattern is not associated with all-cause, CVD and stroke mortality. Further studies are required to confirm these findings.
Inspired by the recent experiment on erythrocytes (red blood cells, RBCs) in weak shear flows by Dupire et al. (Proc. Natl Acad. Sci. USA, vol. 109, 2012, pp. 20808–20813), we conduct a numerical investigation to study the dynamics of RBCs in low-shear-rate flows by applying a multiscale fluid–structure interaction model. By employing a spheroidal stress-free state in the cytoskeleton, we are able to numerically predict an important feature, namely that the cell maintains its biconcave shape during tank-treading motions. Furthermore, we numerically confirm the hypothesis that, as the stress-free state approaches a sphere, the threshold shear rates corresponding to the establishment of tank treading decrease. By comparing with the experimental measurements, our study suggests that the stress-free state of RBCs is a spheroid that is close to a sphere, rather than the biconcave shape applied in existing models (the implication is that the RBC skeleton is pre-stressed in its natural biconcave state). It also suggests that the response of RBCs in low-shear-rate flows may provide a measure to quantitatively determine the distribution of shear stress in the RBC cytoskeleton in the natural state.
Cu0.62Zn0.38 foil was subjected to surface mechanical attrition treatment (SMAT) processing first. Growth behavior of ZnO nanostructure on the SMAT Cu0.62Zn0.38 surface during thermal oxidation was investigated in this paper. The original and SMAT Cu0.62Zn0.38 foils were thermally oxidized at 400 ~ 700 °C under various gaseous environments, including nitrogen and mixture of N2-O2 at a pressure of 1 atm. for 3 h. The oxidized specimens were characterized with a scanning electron microscope, an X-ray diffractometer and a transmission electron microscope. It is found that nanosheets are easily formed on the SMAT specimen surface. The favorable formation of nanosheets relates to twin lamellae structure of Cu0.62Zn0.38 formed during SMAT processing.
Industry-generated trans-fatty acids (TFA) are detrimental to risk of CHD, but ruminant-originated TFA have been reported as neutral or equivocal. Therefore, the total TFA amount should not be the only factor considered when measuring the effects of TFA. In the present study, we addressed whether a version of the TFA index that unifies the effects of different TFA isomers into one equation could be used to reflect CHD risk probability (RP). The present cross-sectional study involved 2713 individuals divided into four groups that represented different pathological severities and potential risks of CHD: acute coronary syndrome (ACS, n 581); chronic coronary artery disease (CCAD, n 631); high-risk population (HRP, n 659); healthy volunteers (HV, n 842). A 10-year CHD RP was calculated. Meanwhile, the equation of the TFA index was derived using five TFA isomers (trans-16 : 1n-7, trans-16 : 1n-9, trans-18 : 1n-7, trans-18 : 1n-9 and trans-18 : 2n-6n-9), which were detected in the whole blood, serum and erythrocyte membranes of each subject. The TFA index and the 10-year CHD RP were compared by linear models. It was shown that only in the erythrocyte membrane, the TFA isomers were significantly different between the groups. In the ACS group, industry-generated TFA (trans-16 : 1n-9, trans-18 : 1n-9 and trans-18 : 2n-6n-9) were the highest, whereas ruminant-originated TFA (trans-16 : 1n-7 and trans-18 : 1n-7), which manifested an inverse relationship with CHD, were the lowest, and vice versa in the HV group. The TFA index decreased progressively from 7·12 to 5·06, 3·11 and 1·92 in the ACS, CCAD, HRP and HV groups, respectively. The erythrocyte membrane TFA index was positively associated with the 10-year CHD RP (R2 0·9981) and manifested a strong linear correlation, which might reflect the true pathological severity of CHD.
Based on 187 galaxy clusters identified from the photometric redshifts of galaxies in the Cosmic Evolution Survey (COSMOS) field(Wen & Han 2011), cluster galaxies brighter than MV = -20.5 are classified into four categories according to their best-fitting templates of the spectral energy distributions (SEDs) provided by Ilbert et al. (2009): early-type (including elliptical and lenticular) galaxies (E+S0), spiral galaxies (S), irregular galaxies (Irr), and starbursts (SB). The fractions of these four SED types are presented as the functions of redshift in Figure 1. Fraction of each category varies remarkably with cluster redshift: fractions of normal galaxies (E+S0+S+Irr) tend to decrease with redshift, whilst the starburst proportion tends to increase with redshift. For the normal galaxies, there exists a sequence for the decreasing slopes of morphological fractions. Majority of the galaxies in high-redshift clusters (z > 1.0) are experiencing strong star-formation activities, which leads to a very high proportion of starburst.
Although ascarid nematodes are important parasites of wild animals of public health concern, few species of ascarids from wild animals have been studied at the molecular level so far. Here, the classification and phylogenetic relationships of roundworms from 21 species of captive wild animals have been studied by sequencing and analysis of parts of the ribosomal 18S and 28S genes and the mitochondrial (mt) 12S gene. Phylogenetic relationships were inferred by 3 methods (NJ/MP/ML) based on the data of single gene sequences and concatenated sequences. Homology analysis indicated that the 18S sequences were conserved among roundworms from all 21 species and that 28S showed interspecies variability. Divergence levels displayed in 12S suggested that 12S appears to be either intra- or interspecifically variable. Evolutionary trees indicated that the ascarids split into 2 families, 4 genera and 7 species, with high bootstrap support for each clade. Combined trees suggested that Baylisascaris ailuri is more closely related to B. transfuga than to B. schroederi. This study provides useful molecular markers for the classification, phylogenetic analysis and epidemiological investigation of roundworms from wild animals.
A coupled model, capable of simulating transonic flow, solid heat conduction, species transport, and gas radiation, is developed that provides better computational treatment of infrared radiation from hot exhaust nozzles. The modeling of gas radiation is based on a statistical narrow-band correlated-k analysis, whose parameters are deduced from the HITEMP line-by-line database. To improve computational efficiency, several methods are employed. A mixed analytical-numerical algorithm is described for the stiffness of the two-equation turbulence model and an alternating direction implicit pretreatment for the ill-conditioned matrix appearing in the coupled problem of flow and solid heat conduction. Moreover, an improved multigrid method and a symmetry plane treatment of the radiation transfer-energy equations are also introduced. Four numerical simulations are given to confirm the efficiency and accuracy of the numerical method. Finally, an account of the aerothermodynamics and infrared characteristics for two types of nozzles are presented. The infrared radiation intensity of the Chevron ejecting nozzle is clearly smaller than that of the common axisymmetric ejecting nozzle. All computations can be performed on a personal computer.
To quantitatively understand the correlation between the molecular structure of an erythrocyte (red blood cell, RBC) and its mechanical response, and to predict mechanically induced structural remodelling in physiological conditions, we developed a computational model by coupling a multiscale approach of RBC membranes with a boundary element method (BEM) for surrounding Stokes flows. The membrane is depicted at three levels: in the whole cell level, a finite element method (FEM) is employed to model the lipid bilayer and the cytoskeleton as two distinct layers of continuum shells. The mechanical properties of the cytoskeleton are obtained from a molecular-detailed model of the junctional complex. The spectrin, a major protein of the cytoskeleton, is simulated using a molecular-based constitutive model. The BEM model is coupled with the FEM model through a staggered coupling algorithm. Using this technique, we first simulated RBC dynamics in capillary flow and found that the protein density variation and bilayer–skeleton interaction forces are much lower than those in micropipette aspiration, and the maximum interaction force occurs at the trailing edge. Then we investigated mechanical responses of RBCs in shear flow during tumbling, tank-treading and swinging motions. The dependencies of tank-treading frequency on the blood plasma viscosity and the membrane viscosity we found match well with benchmark data. The simulation results show that during tank-treading the protein density variation is insignificant for healthy erythrocytes, but significant for cells with a smaller bilayer–skeleton friction coefficient, which may be the case in hereditary spherocytosis.