Effect of Forced Liquid Cooling on the Voltage/Charge Displacement Characteristics of Stacked Piezoelectric Actuators during High-Frequency Drive

Piezoelectric stack actuators (PESAs) are widely used in applications requiring a fast response, high resolution, and high accuracy. The self-heating of a PESA during continuous drive with a large amplitude at high frequencies can change its voltage displacement and charge displacement characteristics. These changes can lead to a loss of stability and inaccurate PESA positioning systems. In this paper, we confirmed that by using our proposed forced liquid cooling, the changes to the dynamic characteristics and the impedance of a PESA due to the fact of self-heating could be reduced. Voltage displacement curve measurements at 10 kHz demonstrated that with natural heat dissipation, the amplitude of PESA increased by 15% due to the self-heating compared to the amplitude measured at the start of driving but only by 3% with forced liquid cooling. The displacement-to-charge ratio decreased by 12% compared to that at room temperature with natural heat dissipation, while it increased by 1% during forced liquid cooling. In the measured frequency response of the voltage displacement transfer function, the increased temperature changed the gain and phase of the first and secondary vibration modes above 20 kHz with natural heat dissipation. Forced liquid cooling also reduced the variations in the frequency response of the voltage displacement transfer function.

Some properties of germanene when adsorption of NH3 in the external field

This work studies on germanene when adsorbing NH3 gas, the system is placed in an 0 external electric field of 0.3 V / AÅ. By using the density functional theory (DFT) and VASP software, the properties of the energy band structure, the density of the state, and the charge displacement have been studied. There are four locations in which NH3 doped research is hollow, bridge, valley, and top. At the bridge position for the minimum adsorption energy, this indicates that the bridge position is the most optimal position when doped with NH3. The state density energy region structure, the charge displacement will be studied for the most optimal position. Placing the system in an external electric field will change the energy band structure as well as other properties of the NH3 doped germanene. This study will be useful for all steps of research in sensor or biomedical.

Charge-Flow Profiles along Curvilinear Paths: A Flexible Scheme for the Analysis of Charge Displacement upon Intermolecular Interactions

The Charge-Displacement (CD) analysis has proven to be a powerful tool for a quantitative characterization of the electron-density flow occurring upon chemical bonding along a suitably chosen interaction axis. In several classes of interesting intermolecular interactions, however, an interaction axis cannot be straightforwardly defined, and the CD analysis loses consistency and usefulness. In this article, we propose a general, flexible reformulation of the CD analysis capable of providing a quantitative view of the charge displacement along custom curvilinear paths. The new scheme naturally reduces to ordinary CD analysis if the path is chosen to be a straight line. An implementation based on a discrete sampling of the electron densities and a Voronoi space partitioning is described and shown in action on two test cases of a metal-carbonyl and a pyridine-ammonia complex.

Reconstruction of a 2D layer of KBr on Ir(111) and electromechanical alteration by graphene

A novel reconstruction of a two-dimensional layer of KBr on an Ir(111) surface is observed by high-resolution noncontact atomic force microscopy and verified by density functional theory (DFT). The observed KBr structure is oriented along the main directions of the Ir(111) surface, but forms a characteristic double-line pattern. Comprehensive calculations by DFT, taking into account the observed periodicities, resulted in a new low-energy reconstruction. However, it is fully relaxed into a common cubic structure when a monolayer of graphene is located between substrate and KBr. By using Kelvin probe force microscopy, the work functions of the reconstructed and the cubic configuration of KBr were measured and indicate, in accordance with the DFT calculations, a difference of nearly 900 meV. The difference is due to the strong interaction and local charge displacement of the K+/Br− ions and the Ir(111) surface, which are reduced by the decoupling effect of graphene, thus yielding different electrical and mechanical properties of the top KBr layer.

Assessing the Orbital Contribution in the “Spodium Bond” by Natural Orbital for Chemical Valence-Charge Displacement Analysis

<p>The term “spodium bond” (SpB) has been recently proposed for the non-coordinative interaction between a polarised group 12 metal and a mild Lewis base. In most of the systems showing short metal-donor distances, however, SpB coexists with other weak interactions, including hydrogen and halogen bonding. Here we show their mutual importance can be probed by dissecting the orbital component of the interaction through the Natural Orbital for Chemical Valence-Charge Displacement analysis. NOCV-CD gives us straightforward snapshots of relative energies and electrons involved, either for model and “real” adducts, allowing us to demonstrate the lack of a direct correlation between a favourable metal-base distance and the presence of an orbital contribution for the SpB.</p>

Assessing the Orbital Contribution in the “Spodium Bond” by Natural Orbital for Chemical Valence-Charge Displacement Analysis

<p>The term “spodium bond” (SpB) has been recently proposed for the non-coordinative interaction between a polarised group 12 metal and a mild Lewis base. In most of the systems showing short metal-donor distances, however, SpB coexists with other weak interactions, including hydrogen and halogen bonding. Here we show their mutual importance can be probed by dissecting the orbital component of the interaction through the Natural Orbital for Chemical Valence-Charge Displacement analysis. NOCV-CD gives us straightforward snapshots of relative energies and electrons involved, either for model and “real” adducts, allowing us to demonstrate the lack of a direct correlation between a favourable metal-base distance and the presence of an orbital contribution for the SpB.</p>

Assessing the Orbital Contribution in the “Spodium Bond” by Natural Orbital for Chemical Valence-Charge Displacement Analysis

<p>The term “spodium bond” (SpB) has been recently proposed for the non-coordinative interaction between a polarised group 12 metal and a mild Lewis base. In most of the systems showing short metal-donor distances, however, SpB coexists with other weak interactions, including hydrogen and halogen bonding. Here we show their mutual importance can be probed by dissecting the orbital component of the interaction through the Natural Orbital for Chemical Valence-Charge Displacement analysis. NOCV-CD gives us straightforward snapshots of relative energies and electrons involved, either for model and “real” adducts, allowing us to demonstrate the lack of a direct correlation between a favourable metal-base distance and the presence of an orbital contribution for the SpB.</p>

Quantifying the Orbital Contribution in the “Spodium Bond” via Natural Orbital for Chemical Valence-Charge Displacement Analysis

<p>The term “spodium bond” (SpB) has been recently proposed for the non-coordinative interaction between a polarised group 12 metal and a mild Lewis base. In most of the systems showing short metal-donor distances, however, SpB coexists with other weak interactions, including hydrogen and halogen bonding. Here we show their mutual importance can be probed by dissecting the orbital component of the interaction through the Natural Orbital for Chemical Valence-Charge Displacement analysis. NOCV-CD gives us straightforward snapshots of relative energies and electrons involved, either for model and “real” adducts, allowing us to demonstrate the lack of a direct correlation between a favourable metal-base distance and the presence of an orbital contribution for the SpB.</p>