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Spin qubits based on silicon metal-oxide semiconductor (Si-MOS) quantum dots (QDs) are promising platforms for large-scale quantum computers. To control spin qubits in QDs, electric dipole spin resonance (EDSR) has been most commonly used in recent years. By delocalizing an electron across a double quantum dots charge state, flopping-mode EDSR has been realized in Si/SiGe QDs. Here, we demonstrate a flopping-mode spin qubit in a Si-MOS QD via Elzerman single-shot readout. When changing the detuning with a fixed drive power, we achieve s-shape spin resonance frequencies, an order of magnitude improvement in the spin Rabi frequencies, and virtually constant spin dephasing times. Our results offer a route to large-scale spin qubit systems with higher control fidelity in Si-MOS QDs., Comment: 5 pages, 4 figures

Tunable synthetic spin-orbit coupling (s-SOC) is one of the key challenges in various quantum systems, such as ultracold atomic gases, topological superconductors, and semiconductor quantum dots. Here we experimentally demonstrate controlling the s-SOC by investigating the anisotropy of spin-valley resonance in a silicon quantum dot. As we rotate the applied magnetic field in-plane, we find a striking nonsinusoidal behavior of resonance amplitude that distinguishes s-SOC from the intrinsic spin-orbit coupling (i-SOC), and associate this behavior with the previously overlooked in-plane transverse magnetic field gradient. Moreover, by theoretically analyzing the experimentally measured s-SOC field, we predict the quality factor of the spin qubit could be optimized if the orientation of the in-plane magnetic field is rotated away from the traditional working point., Comment: 26 pages, 10 figures

In silicon quantum dots (QDs), at a certain magnetic field commonly referred to as the "hot spot", the electron spin relaxation rate (T_1^(-1)) can be drastically enhanced due to strong spin-valley mixing. Here, we experimentally find that with a valley splitting of 78.2 ${\pm}$ 1.6 ${\mu}$eV, this hot spot in spin relaxation can be suppressed by more than 2 orders of magnitude when the in-plane magnetic field is oriented at an optimal angle, about 9{\deg} from the [100] sample plane. This directional anisotropy exhibits a sinusoidal modulation with a 180{\deg} periodicity. We explain the magnitude and phase of this modulation using a model that accounts for both spin-valley mixing and intravalley spin-orbit mixing. The generality of this phenomenon is also confirmed by tuning the electric field and the valley splitting up to 268.2 ${\pm}$ 0.7 ${\mu}$eV., Comment: 13 pages and 4 figures for Manuscript, 17 pages and 7 figures for Supplementary material

Semiconductor nanowires have been playing a crucial role in the development of nanoscale devices for the realization of spin qubits, Majorana fermions, single photon emitters, nanoprocessors, etc. The monolithic growth of site-controlled nanowires is a prerequisite toward the next generation of devices that will require addressability and scalability. Here, combining top-down nanofabrication and bottom-up self-assembly, the growth of Ge wires on prepatterned Si (001) substrates with controllable position, distance, length, and structure is reported. This is achieved by a novel growth process that uses a SiGe strain-relaxation template and can be potentially generalized to other material combinations. Transport measurements show an electrically tunable spin-orbit coupling, with a spin-orbit length similar to that of III-V materials. Also, charge sensing between quantum dots in closely spaced wires is observed, which underlines their potential for the realization of advanced quantum devices. The reported results open a path toward scalable qubit devices using nanowires on silicon.

A novel type of single use bi-stable MEMS solid off-on switch based on metal bridge igniter is described and its performance test results are presented. The switch mechanically connects a couple of comb electrodes which belong separately to different metallic lines. Switching between the two stable states (off and on) is accomplished by a voltage pulse supplied by an energy storage capacitance through a metal bridge igniter above the electrical lines to be connected. The switch can be driven by external signal and its predicted lifetime is very long, therefore the switch can be used for long term store systems.

To determine the hydrocarbon - generating characteristics of Shuangyang Formation in Well Chang 27.We selected dark mudstone in Shuangyang Formation to launch Rock-Eval (open system) thermal simulation. Through thermal simulation data to demarcate a kinetic model,the Shuangyang Stratum mudstone samples reveal the gas intensity is mainly distributed in (210~230) kJ/mol),the average activation energy is 223kJ/mol. The hydrocarbon - generating characteristics of Shuangyang Formation in Well Chang 27 whose hydrocarbon generation stage mainly in the period (37~24) Ma, corresponding the late period of the Yongji Formation deposition to the late period of the Qijia Formation deposition. In Chang 27 Well area,the average generating strength of gas in Shuangyang Formation is (21~37×108) m3·km2. The hydrocarbon generation stage of Shuangyang Formation in Chang 27 Well area is mainly in (37~24) Ma, corresponding to the late deposition period of the Yongji Formation and Qijia Formation. Both the shorter periods of hydrocarbon generation and late hydrocarbon generation period made great contributions to accumulation, in which Shuang_1 formation played a bigger role.

The paper mainly designs an efficient MEMS electrothermal actuator, with lower voltage input but large displacement output. The calculation method of the actuator considers the convection and radiation besides heat conduction mentioned in most literatures. With the multiphysics simulation by the software Comsol of electrothermal bimorph actuator, the transient effects of thermal convection and thermal radiation on the actuator displacement and the response characteristics of an actuator with a separate heating layer were studied.

The experiment is carried out in a 13-meter-high circulating fluidized bed(CFB) to investigate gas-solid two-phase flow by pressure sensor. The axial pressure and pressure fluctuation are measured in different solid mass fluxes. With the solid mass flux increasing, pressure gradually increases, and pressure gradually decreases along the riser upwards. The characteristic of pressure fluctuation in the riser is analyzed, which indicates that pressure fluctuation in the riser originates from the inlet. The intensity of the pressure fluctuation decreases along the riser upwards. This pressure fluctuation is composed of two types: one is of low frequency and high amplitude, which is resulted from unstable feeding to the riser and keeps coherent along the axial direction. And the other is of high frequency and low amplitude, which is the result of a variety of factors, such as cluster movement, gas-solid interaction and gas velocity fluctuation.