Anharmonic guest atom oscillation has direct connection to the thermal transport and thermoelectric behavior of type-I Ba8Ga16Sn30 clathrates. This behavior can be observed through several physical properties, with fo...
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Anharmonic guest atom oscillation has direct connection to the thermal transport and thermoelectric behavior of type-I Ba8Ga16Sn30 clathrates. This behavior can be observed through several physical properties, with for example the heat capacity providing a measure of the overall excitation level structure. Localized anharmonic excitations also influence the low-temperature resistivity, as we show in this paper. By combining heat capacity, transport measurements, and our previous NMR relaxation results, we address the distribution of local oscillators in this material, as well as the shape of the confining potential and the excitation energies for Ba(2) ions in the cages. We also compare to the soft-potential model and other models used for similar systems. The results show good agreement between the previously deduced anharmonic rattler potential and experimental data.
Central to most applications involving graphenes flakes is its mechanical response under various stress/ strain states. In this work, we present an experimental study on single, bi- and tri-layer graphene flakes under...
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ISBN:
(纸本)9788888785332
Central to most applications involving graphenes flakes is its mechanical response under various stress/ strain states. In this work, we present an experimental study on single, bi- and tri-layer graphene flakes under uniaxial tensile strain, for low levels of strain. Graphene layers were subjected to tensile loading by employing a polymeric cantilever beam assembly, where the graphene flakes are embedded into the polymer beam. The mechanical response of graphenes is monitored by simultaneous Raman measurements through the shift of the G and 2D optical phonons, and their strain sensitivities are determined. The results can be used to quantify the amount of uniaxial strain, providing a fundamental tool for graphene based nanocomposites.
Early detection of living bacteria attracts a lot of attention in infection diseases applications, especially at low concentration. Nowadays, the detection of specific bacteria faces challenges including enhancement o...
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Early detection of living bacteria attracts a lot of attention in infection diseases applications, especially at low concentration. Nowadays, the detection of specific bacteria faces challenges including enhancement of trapping efficiency, and increase of sensor sensitivity and specificity. In this study, we improved the trapping efficiency and increased sensor sensitivity and specificity by using AC electrokinetics and selective modification of antibody on gold electrode in a new structure of gold electrode design. COMSOL simulations of AC electrokinetics include dielectrophoresis (DEP), and AC electroosmosis (ACEO) were performed on different electrode designs and bias configurations. The simulation results were consistent with the fluorescence observations showing that the bacteria were trapping selectively on gold electrodes. The impedance measurements for Vibrio parahaemolyticus (Vp) detection at 105 cfu/ml with AC elctrokinetics showed a nearly 90% change in normalized impedance change (NIC).
Bistable structures associated with nonlinear deformation behavior, exemplified by the Venus flytrap and slap bracelet, can switch between different functional shapes upon actuation. Despite numerous efforts in modeli...
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Bistable structures associated with nonlinear deformation behavior, exemplified by the Venus flytrap and slap bracelet, can switch between different functional shapes upon actuation. Despite numerous efforts in modeling such large deformation behavior of shells, the roles of mechanical and nonlinear geometric effects on bistability remain elusive. We demonstrate, through both theoretical analysis and tabletop experiments, that two dimensionless parameters control bistability. Our work classifies the conditions for bistability, and extends the large deformation theory of plates and shells.
Hard poly（vinyl chloride） （PVC）/acrylonitrile-butadiene-styrene （ABS） blends were prepared using injection- molding and influence of crosshead speed on mechanical properties was examined. Based on morphology par...
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Hard poly（vinyl chloride） （PVC）/acrylonitrile-butadiene-styrene （ABS） blends were prepared using injection- molding and influence of crosshead speed on mechanical properties was examined. Based on morphology parameters obtained from transmission electron microscopy photography and the material parameters from true stress-strain curves of neat PVC and ABS, yield stresses of the blends at different crosshead speeds were simulated employing a two-dimensional nine-particle model based on the finite element analysis （FEA）. The FEA results were compared with the experimental yielding stress and the good agreement validated the simulation approach. The FEA approach allowed establishing a yielding criterion related to local yielding of the interstitial matrix between ABS particles.
We studied cycle time （0.01-10 s with triangular input waves） and poling history （continuous versus fresh poling） dependent electric energy storage and discharge behaviors in poly（vinylidene fluoride-co-hexafluor...
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We studied cycle time （0.01-10 s with triangular input waves） and poling history （continuous versus fresh poling） dependent electric energy storage and discharge behaviors in poly（vinylidene fluoride-co-hexafluoropropylene） [P（VDF- HFP）] films using the electric displacement -- the electric field （D-E） hysteresis loop measurements. Since the permanent dipoles in PVDF are orientational in nature, it is generally considered that both charging and discharging processes should be time and poling history dependent. Intriguingly, our experimental results showed that the charging process depended heavily on the cycle time and the prior poling history, and thus the D-E hysteresis loops had different shapes accordingly. However, the discharged energy density did not change no matter how the D-E loop shape varied due to different measurements. This experimental result could be explained in terms of reversible and irreversible polarizations. The reversible polarization could be charged and discharged fairly quickly （〈 5 ms for each process）, while the irreversible polarization depended heavily on the poling time and the prior poling history. This study suggests that it is only meaningful to compare the discharged energy density for PVDF and its copolymer films when different cycle times and poling histories are used.
In this paper, a multi-functional of multi-layer planar micro-coils chip is demonstrated to play as actuators and heaters. For playing as actuators, the micro-coil generate local magnetic field with applied current of...
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In this paper, a multi-functional of multi-layer planar micro-coils chip is demonstrated to play as actuators and heaters. For playing as actuators, the micro-coil generate local magnetic field with applied current of 15 mA to quickly manipulated magnetic beads to center of micro-coil within one minute. For functioning as heaters, the micro-coil heater can be quickly heated up to denatured temperature of 95 °C with input power of 50.5 mW, and its heating and cooling rate are 19.7 and 11.8 °C/s, respectively. For the typical 25 polymerase chain reaction (PCR) cycles, it took only 770 seconds. To further shrink and optimize the multi-layer planar micro-coils chip can be possibly used to manipulate single cell with magnetic beads to specific region and analyze its gene sequence by using single cell PCR technique.
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