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The ultrasonic signal changes the contact area between the conducting grains in the sample structure and then resistance is modulated by the frequency of ultrasonic excitation.
In case the contact area between the conducting grains is changing then the current density is changed.
The resulting resistance change depends on the size of crack, shape of crack, number of cracks and orientation of cracks against direction of the ultrasonic wave.
The resulting resistance change depends on the size of crack, shape of crack, number of cracks and orientation of cracks against direction of the ultrasonic wave.

Nanocrystalline tungsten carbide powders with large surface area can provide a large number of catalytic active centers (situ) to reactions.
The nanocrystalline WC powder with average 40 nm grain size was synthesized by embedment-direct reduction and carburization at 1300℃ and 3 hours' heat preservation.
Nanocrystalline tungsten carbide powders with large surface area can provide a large number of catalytic active centers (situ) to reactions.
Fig. 4 SEM of WC (a) powder without pretreatment and aftertreatment (b) powder with pretreatment, without aftertreatment (c) powder with pretreatment and aftertreatment As the Fig.4 shown, the powders were agglomerations of the WC grains.

In the last 50 years a number of results (mainly obtained by studying the flow of liquids through thin lyophobic capillaries) have cast doubts on the universality of the no-slip condition, and have shown that under certain conditions fluid slippage might occur at the solid boundary.
Results and discussion Permeating performance The nano grains deposits on the surface of the alumina particles [7].
The nano coating is formed by the aggregation of those nano grains.
According to the EDL model, the adsorbed layer is thin because the large numbers of counter-ions are in the diffused layer.

We can see the existence of large numbers of Cr2O3 at 950 °C for 2h (in Fig. 2b), indicating that the formation of Cr3C2 is closely related to the reaction kinetics.
Here, larger numbers of Cr2O3 phases can be observed in reaction products at 1000 °C for only 1 h, showing that these phases have not been transformed completely to single phase of Cr3C2.
The significant grain growth of Cr3C2 powders exists at 900-1000 °C.
In addition, synthesizing time can also hasten the grain growth of Cr3C2 powders (as shown in Fig. 3b and 3c ).

The aim of the work is to identify the best processing conditions for the manufacturing of near-net-shape, chemically-homogeneous and fine-grained Ti-6Al-7Nb components.
The morphology of the Ti-6Al-7Nb powder was analysed by SEM and a representative example is reported in Figure 3 where it can be seen that the three powders used to produce the Ti-6Al-7Nb alloy powder, which could be clearly distinguished using the BSE mode due to the different atomic number of the elements, have very similar particle size and morphology.
With the increment of the sintering temperature the pores get more spherical and tend to move towards the grain boundaries and coalesce at three-point boundaries.
The processing of the Ti-6Al-7Nb at 1100ºC by means of IHP (Figure 7 a) leads to a heterogeneous microstructure composed by grains and α + β acicular grains.
When the sintering temperature is set to 1300ºC, the microstructure obtained resembles that of the samples processed at 1100ºC because is still composed by alpha grains and fine α + β acicular grains.

Materials with coarse grains, according to the theory postulated by Griffith's [9] on fractures, will be less resistant than those of fine grains.
If the deformation is continuous new grains will grow inside the one deformed, so it will be more brittle and more easily comminuted.
Coarse-grained Porphyritic Syenogranite 0.80 1.52 142.20 1.26 0.54 0.72 0.08 White Dallas 40% K-f; 25% Qz; 15% Pl 10% Gr; 5% Bt; 5% Sil.
Coarse-grained, heterogranular Charnokite 0.77 1.37 127.20 0.93 0.27 0.71 0.18 Green Butterfly 50% K-f; 30% Pl; 12% Qz; 8% Opx.
In fact, standard deviations of sawing input consumption are so big that those values cannot be correlated to detailed observations of petrographic features on the samples, as we would be comparing numbers in such different scales that it would not be reliable.

The top side has a higher exposure to heat from friction, resulting in a larger grain size, while in the BNZ, there is less exposure to heat and the grain size is smaller.
The middle zone of the nugget (MNZ) shows moderate grain size.
Therefore, heat plays an essential role in grain size and morphology.
In addition, each type of machine has a number of defining characteristics in the execution of the operation, the quality and productivity of the process.
As a result, the final grain structure was found to contain a series of microstructures developed in different ways, either by initial grain recrystallization or subgrains formed by dynamic recovery.

Microalloying elements (V, Ti, Al, Nb) are responsible for the fine-grained microstructure.
The fine-grained, basically martensitic microstructure of the base material is illustrated in Fig. 4 with the characteristic grain orientation (elongated grains) due to the thermos-mechanical rolling process.
The complete austenitization does not take place here, because the energy or time requirements for this are not met, only at the grain boundaries at the most.
The original fine-grained microstructure of the base material changes in this zone.
Acknowledgement The financial support of the János Bolyai Research Scholarship of the Hungarian Academy of Sciences is gratefully acknowledged (Grant number: Bo/00643/22/6).

Pure soil grain was taken as blank experiment.
The bud number and bud length were recorded every day.
During the whole experiment term, the number of buds and the bud length were recorded every day.
Germination rate= ( Eq. 1) M1, the number of buds; M, the number of seeds for the experiment.
Germinability= ( Eq. 2) M2, the number of buds summed during the required term; M, the number of seeds for the experiment.

That causes the resistance of iron movement increases, and the ability to dissolve and diffusion decreases, which makes it easy to form a dense layer of lead sulfate crystalline grain on the lead electrode.
After the crystalline grain covering the electrode surface, the electrode is separated from the sulfuric acid electrolyte, resulting in the shutoff of the reaction and electrode passivation [7].
Figure 1: Microtopography of carbon material (10μm) It is shown in Table 3 that the first HRPSoC cycle number of the battery without carbon addition in the cathode got the result that the first HRPSoC cycle number was 926, and the second cycle number was 635.
However, with the increase of the content of 2#C, the HRPSoC cycle number didn't show monotonic increasing phenomenon.
The two HRPSoC cycle number of 0.3% and 0.9% carbon content battery are 14732, 11751, 15724 and 15732.