Universal enhancement of vacancy diffusion by Mn inducing anomalous Friedel oscillation in concentrated solid-solution alloys

We present a proof-of-principle demonstration of a universal law for the element Mn, which greatly enhances vacancy diffusion through an anomalous Friedel Oscillation effect in a series of Ni-based concentrated solid-solution alloys, regardless of the type of atom involved. The antiferromagnetic element Mn possesses a unique half-filled 3d electron structure, creating split virtual bound states near the Fermi energy level and producing a large local magnetic moment after vacancy formation. The resultant electron spin oscillations reduce the number of electrons involved in charge density oscillations, destroying charge screening and lowering potential interaction at the saddle point between the vacancy and diffusing atom. This ultimately facilitates vacancy diffusion by reducing energy level variations of conduction band electrons during the diffusion process. These findings offer valuable insights into atom diffusion mechanisms and open up new avenues for manipulating defect properties through unique element design, thereby enabling the creation of high-performance alloys in a broad range of fields

The Impact of Whole Brain Global Functional Connectivity Density Following MECT in Major Depression: A Follow-Up Study

To explore the alteration of global functional connectivity density (gFCD) in depressive patients after modified electroconvulsive therapy (MECT) and analyze the relationship between gFCD and clinical outcome. Thirty-seven subjects were evaluated based on the diagnostic criteria of the International Classification of Diseases-10 (ICD-10), consisting of a depressive group (24 patients after follow-ups) and a healthy control group with 13 normal individuals. All participants received Hamilton Depression Scale (HAMD) scores and resting-state functional magnetic resonance imaging scans. The gFCD significantly increased in the posterior-middle insula, the supra-marginal gyrus and the dorsal medial prefrontal cortex (dmPFC) before MECT treatment compared to healthy controlled patients. The gFCD statistically expanded in the perigenual anterior cingulate cortex (pgACC), the orbitofrontal cortex bilaterally and the left-supra-marginal gyrus after MECT, and it decreased notably in the posterior insula. The gFCD in the pgACC and the right orbital frontal cortex of depressive group before MECT showed a positive correlation with HAMD scores with treatment. Conforming to the impact of gFCD in depressive patients after MECT, the aforementioned brain region may become an indicator of MECT effect

Energy-efficient Integrated Optical Phased Array on Silicon-on-Insulator Platform

As a non-mechanical beam steering technique, optical phased array (OPA) is becoming a promising method for solid-state light detection and ranging (LiDAR) andfree-space optical communication. Significant progress has been achieved for the integrated OPA, such as large scalability, low power consumption, and large beam steering range. Moreover, silicon photonics is becoming a mature technique for large-scale photonic integrated circuits (PICs) owing to its compatibility with Complementary Metal Oxide Semiconductor (CMOS) process. Now, silicon photonics has been widely regarded as a suitable platform for large-scale OPA integration. In this thesis, we successfully demonstrated two kinds (racetrack-spiral and roundspiral) of energy-efficient silicon integrated optical phase shifter based on the thermooptic effect. Besides the low power consumption of the proposed phase shifters, they also exhibit a well-balanced overall performance on low insertion loss, high modulation bandwidth, and a small footprint. The best experimental result that we have already achieved on a round-spiral phase shifter for the insertion loss, power consumption, modulation bandwidth, and footprint are 0.6 dB, 3.1 mW/π, 34 kHz, and 42 µm × 42 µm, respectively. The proposed round-spiral phase shifter can benefit the large-scale silicon photonics integrated circuits as an efficient fundamental unit and is already been used in large-scale OPAs. By utilizing the well-balanced performance phase shifter, we fabricated two energyefficient 120-channel 1D-OPAs. The first demonstrated 1D-OPA utilizes Gaussian power distribution in both horizontal (φ) and vertical (θ) directions to achieve high sidelobe suppression ratios (15.1 dB and 25.8 dB, respectively). The steering angle range is 25° × 13.2°, and the beamwidth is 0.31° × 0.07° with an aperture size of 0.363 mm × 2 mm. The measured total power consumption and efficiency are 332 mW and 2.7 mW/π. The second demonstrated 1D-OPA has ultra-sparse nonuniform pitches to achieve high resolution of 0.13° and large steering angle range of 162° × 13.7°. The maximum side lobe suppression ratio (SLSR) is measured to be 6 dB. The measured total power consumption and efficiency are 469 mW and 3.5 mW/π. An attempt on large-scale 2D-OPA has been made. we fabricate a 32 × 32 2D-OPA with a uniform pitch of 28 µm. Next step, the 2D-OPA will be characterized

Energy-efficient integrated silicon optical phased array

Abstract An optical phased array (OPA) is a promising non-mechanical technique for beam steering in solid-state light detection and ranging systems. The performance of the OPA largely depends on the phase shifter, which affects power consumption, insertion loss, modulation speed, and footprint. However, for a thermo-optic phase shifter, achieving good performance in all aspects is challenging due to trade-offs among these aspects. In this work, we propose and demonstrate two types of energy-efficient optical phase shifters that overcome these trade-offs and achieve a well-balanced performance in all aspects. Additionally, the proposed round-spiral phase shifter is robust in fabrication and fully compatible with deep ultraviolet (DUV) processes, making it an ideal building block for large-scale photonic integrated circuits (PICs). Using the high-performance phase shifter, we propose a periodic OPA with low power consumption, whose maximum electric power consumption within the field of view is only 0.33 W. Moreover, we designed Gaussian power distribution in both the azimuthal ( $$\varphi$$ φ ) and polar ( $$\theta$$ θ ) directions and experimentally achieved a large sidelobe suppression ratio of 15.1 and 25 dB, respectively. Graphical Abstrac

Energy-efficient Silicon Optical Phased Array with Ultra-sparse Nonuniform Spacing

We experimentally demonstrate an ultra-sparse 120-channel silicon optical phased array with a large aperture size of 6 mm × 5 mm. A 162° field of view was achieved with a total power consumption of 0.47 W and thermo-optic power efficiency of 3.1 mW/π