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Semiconductor quantum dot arrays defined electrostatically in a 2D electron gas provide a scalable platform for quantum information processing and quantum simulations. For the operation of quantum dot arrays, appropriate voltages need to be applied to the gate electrodes that define the quantum dot potential landscape. Tuning the gate voltages has proven to be a time-consuming task, because of initial electrostatic disorder and capacitive cross-talk effects. Here, we report on the automated tuning of the inter-dot tunnel coupling in gate-defined semiconductor double quantum dots. The automation of the tuning of the inter-dot tunnel coupling is the next step forward in scalable and efficient control of larger quantum dot arrays. This work greatly reduces the effort of tuning semiconductor quantum dots for quantum information processing and quantum simulation.

AbstractDipolarization fronts (DFs) have been suggested as crucial energy conversion sites contributing significantly to global energy transfer in the magnetosphere. However, energy partitioning of DF‐driven energy transfer remains hitherto elusive. Using high‐cadence data from MMS spacecraft, we present a detailed investigation of energy flux densities at two DFs with/without surface ripples. We find that during both DF intervals, electron enthalpy flux increases dramatically, carries the greatest energy, and well correlates with local energy conversion. Poynting flux also increases but contributes to a relatively smaller portion. Ion enthalpy flux which in magnitude is slightly smaller than electron enthalpy flux barely changes. Particle kinetic energy and heat fluxes are negligible. Strong difference in energy fluxes observed by different spacecraft is found at the rippled DF, indicating three‐dimensional energy transport. These results indicate that energy budgets at the DFs are dominated by electron physics, rather than ion dynamics suggested by previous studies.

The control and regulation of thermal fields is of great significance in solving various thermal management problems in human life. Benefitting from the emerging space transformation technique and thermal meta-material, thermal meta-structures with unique thermal control capabilities have been rapidly developed in recent years. However, the exploration of the functional diversity of thermal meta-materials and structures is still inadequate; most related works are still limited to the single-field control effect and lack sensitivity to external environment changes. For the designed functional structures, observation and analysis of energy fluctuations and irreversible heat loss during the regulation process of the diffusive thermal field are also scare. Therefore, in this current work, we design a thermal meta-regulator (based on the space transformation theory) that is capable of differently distributing thermal energy according to the heat input direction and switching field control pattern with the change of ambient temperature. In addition to the common indicator of temperature, we also introduce the local entropy production rate and the total entropy production in the thermo-dynamic category to carry out entropy analysis of the energy processes involved in the thermal meta-regulator, making a multi-angle evaluation of the structural performance. Furthermore, we use the statistical response surface method to explore the comprehensive/interaction effect of multiple influencing factors on the thermal meta-regulator; the derived regression equations can be used to accurately predict the structural effects under different design schemes and temperature conditions. Our work further enriches the diversity and flexibility of thermal field manipulation manners and the demonstrated functions are also expected to be realized in other physical fields.

CF4 is a strong greenhouse gas of both anthropogenic and natural origin [D.R. Worton et al., Environ. Sci. Technol. 41, 2184 (2007)]. However, high-resolution infrared spectroscopy of this molecule has received only a limited interest up to now. Until very recently, the public databases only contained cross-sections for this species, but no detailed line list. We reinvestigate here the strongly absorbing ν3 region around 7.8 μm. New Fourier transform infrared (FTIR) spectra up to a maximal resolution of 0.0025 cm−1 have been recorded: (i) room-temperature spectra in a static cell and (ii) a supersonic expansion jet spectrum at a 23 K estimated temperature. Following the work of Gabard et al. [Mol. Phys. 85, 735 (1995)], we perform a simultaneous analysis of both the ν3 and 2ν4 bands since a strong Coriolis interaction occurs between them, perturbing the ν3 R-branch rotational clusters around J = 20. Similarly to Gabard et al. , we also include ν4 FTIR data and microwave data in the fit. The analysis is pe...

Abstract Some new structures of thin-film solar converters (SC) based on heterojunctions (HJ) with intermediate semiconductor layers are suggested. Thin protective layers and a quasi-electric field incorporated into the space charge region (SCR) prevent cross-diffusion of HJ components and increase efficiency of charge carrier separation. They also decrease the diode dark current and provide high stability of the converter parameters. Thin (∼ 0.1 μ M) (CdSe) x (ZnTe) 1− x or Zn x Cd 1− x Se layers were used as graded band-gap layers. They were places between a photosensitive II-VI-compound (CdTe, CdSe, CdSe x Te 1− x ) base layer and the transparent Cu 1.8 S layer. The above structures were prepared by vacuum closed space sublimation. The properties of these compounds were studied by electron microscopy and X-ray photoelectron spectroscopy (XPS) with ion etching. The photoelectron properties of structures such as Cu 1.8 S/(CdSe) x )(ZnTe) 1− x /CdSe are presented in detail. The manufacturing technology for the integrated solar batteries based on CdTe, CdSe, and CdSe x Te 1− x compounds was developed. The solar cell parameters under low illumination intensities are comparable to those of solar batteries based on c-Si and a-Si. The competitiveness of the polycrystalline thin-film SC is due to ease and low cost of fabrication (as compared with c-Si and a-Si) and also to the extended photosensitivity range (as compared to a-Si).

Partial discharge (PD) ultrasonic detection is an early sign of the insolation defects of power transformers. The early diagnosis of PD requires the high sensitivity and reliability of ultrasonic sensing systems. For this purpose, a reformative PD ultrasonic sensing system based on phase-shifted FBG (PS-FBG) was demonstrated. By using PS-FBG as the ultrasonic sensing unit, the ultrasonic sensing system improved the response to the ultrasonic signal and overcame the electromagnetic noise. To compensate for the influence of temperature change on the ultrasonic sensing system, an automatic wavelength scanning demodulating method was carried out. The wavelength spanning strategy was optimized based on the principle of cross-correlation, in order to quicken the spanning. A PD detection test in the transformer oil was conducted, and the result shows that PS-FBG was 17.5 times more sensitive than PZT. Because of the better ultrasonic response, the proposed system was able to achieve the early diagnosis of insolation faults in a power transformer.

The influence of the transparent conducting oxide (TCO) topography was studied on the performance of a silicon oxide intermediate reflector layer (IRL) in a-Si/μc-Si tandem cells, both experimentally and by 3-D optical simulations. Therefore, cells with varying IRL thickness were deposited on three different types of TCOs. Clear differences were observed regarding the performance of the IRL as well as its ideal thickness, both experimentally and in the simulations. Optical modeling suggests that a small autocorrelation length is essential for a good performance. Design rules for both the TCO topography and the IRL thickness can be derived from this interplay.