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Electrostatic MEMS micromirrors usually work in resonant state to obtain large amplitude of torsion angle. The real-time prediction of MEMS micromirror torsion angle is calculated according to the measured resonant amplitude and phase under the assumption that the relationship between the torsion angle and time is sinusoidal. However, there are few reports on the deviation of this torsion angle predication based on sinusoidal assumption. In this paper, the real resonant torsion trajectory of C1100 MEMS micromirror under different driving frequencies and voltages is measured by using microscopic laser Doppler method, and the deviation between the real trajectory and the trajectory fitted by sinusoidal curve is compared. The results show that the real trajectory of the MEMS micromirror driven by square wave is not completely consistent with the sinusoidal estimation, and the deviation increases with the increase of the torsional angle amplitude. By obtaining the frequency domain components of the torsion angle signal using FFT method, the main reason of this prediction deviation is due to composition of harmonic signals on base frequency signal. The research results reveal that the sinusoidal assumption method is only suitable for situations when the optical angle accuracy is less than 0.1°.

Tumor immune escape caused by low levels of tumor immunogenicity and immune checkpoint‐dependent suppression limits the immunotherapeutic effect. Herein, a "two‐way regulation" epigenetic therapeutic strategy is proposed using a novel nano‐regulator that inhibits tumor immune escape by upregulating expression of tumor‐associated antigens (TAAs) to improve immunogenicity and downregulating programmed cell death 1 ligand 1 (PD‐L1) expression to block programmed death‐1 (PD‐1)/PD‐L1. To engineer the nano‐regulator, the DNA methyltransferase (DNMT) inhibitor zebularine (Zeb) and the bromodomain‐containing protein 4 (BRD4) inhibitor JQ1 are co‐loaded into the cationic liposomes with condensing the toll‐like receptor 9 (TLR9) agonist cytosine‐phosphate‐guanine (CpG) via electrostatic interactions to obtain G‐J/ZL. Then, asparagine–glycine–arginine (NGR) modified material carboxymethyl‐chitosan (CMCS) is coated on the surface of G‐J/ZL to construct CG‐J/ZL. CG‐J/ZL is shown to target tumor tissue and disassemble under the acidic tumor microenvironment (TME). Zeb upregulated TAAs expression to improve the immunogenicity; JQ1 inhibited PD‐L1 expression to block immune checkpoint; CpG promote dendritic cell (DC) maturation and reactivated the ability of tumour‐associated macrophages (TAM) to kill tumor cells. Taken together, these results demonstrate that the nano‐regulator CG‐J/ZL can upregulate TAAs expression to enhance T‐cell infiltration and downregulate PD‐L1 expression to improve the recognition of tumor cells by T‐cells, representing a promising strategy to improve antitumor immune response. [ABSTRACT FROM AUTHOR]

Improving the Curie temperature and catalytic performance of two-dimensional magnetic materials through elemental doping is a feasible strategy. In this study, Ni-doped (Fe1−xNix)5GeTe2 (0 ≤ x ≤ 0.3) single crystals were grown via chemical vapor transport method and the amount of Ni doping could be precisely controlled. As the amount of Ni doping increases, the long-range ferromagnetic ordering temperature increased, and (Fe0.7Ni0.3)5GeTe2 exhibited the highest Curie temperature Tc = 492.73 K. The improvement of Tc can be attributed to the occupancy of the Fe1 site by Ni atoms. The oxygen evolution reaction (OER) activities of liquid phase exfoliated (Fe1−xNix)5GeTe2 nanoflakes were enhanced by doping Ni atoms, and the overpotential decrease to 464 mV at 10 mA/cm2 with a small Tafel slope of 41 mV/dec for the (Fe0.9Ni0.1)5GeTe2 nanoflakes. Based on the density functional theory calculations, when half of the Fe1 sites were replaced by Ni atoms, the number of enhanced OER active sites (Fe1-Te sites) reached maximum, and then, (Fe0.9Ni0.1)5GeTe2 exhibited the best catalytic performance. The experimental and theoretical calculation results indicate that replacing Fe1 site with Ni in two-dimensional magnetic Fe5GeTe2 can effectively increase the Curie temperature and enhance OER activity. [ABSTRACT FROM AUTHOR]

As a two-dimensional material with a hollow hexatomic ring structure, Néel-type anti-ferromagnetic (AFM) GdI3 can be used as a theoretical model to study the effect of electron doping. Based on first-principles calculations, we find that the Fermi surface nesting occurs when more than 1/3 electron per Gd is doped, resulting in the failure to obtain a stable ferromagnetic (FM) state. More interestingly, GdI3 with appropriate Mg/Ca doping (1/6 Mg/Ca per Gd) turns to be half-metallic FM state. This AFM–FM transition results from the transfer of doped electrons to the spatially expanded Gd-5d orbital, which leads to the FM coupling of local half-full Gd-4f electrons through 5d–4f hybridization. Moreover, the shortened Gd–Gd length is the key to the formation of the stable ferromagnetic coupling. Our method provides new insights into obtaining stable FM materials from AFM materials. [ABSTRACT FROM AUTHOR]

As a cubic perovskite structure material with a wide bandgap of 3.1 eV, BaSnO3 has various functional applications due to its excellent light transmission, electric conductivity, and heat resistance. By doping with a small amount of transition, metal ions may further introduce ferromagnetism in BaSnO3 and extend its functions to spintronics. In this work, 5% Cu ions (atomic ratio) have been doped into BaSnO3 (Ba0.95Cu0.05SnO3) prepared by solid state reaction, which is further annealed in argon or oxygen atmosphere to obtain different concentrations of oxygen vacancies. Clear room temperature ferromagnetism with saturated magnetization of about 0.0025 emu/g has been observed in the as-prepared Cu-doped BaSnO3, which is strongly suppressed after annealing in both argon and oxygen conditions. First-principles calculations suggest that the magnetic properties of Cu-doped BaSnO3 may come from the ferromagnetic Cu clusters embedding in BaSnO3. In addition, oxygen vacancies in the appropriate position help to strengthen the ferromagnetic coupling between adjacent Cu ions. Our results clearly demonstrate the fine tuning of oxygen vacancies, not only concentration, but also locations, may significantly influence the magnetic states of Cu-doped BaSnO3. [ABSTRACT FROM AUTHOR]