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A novel cobweb-like disk resonator gyroscope (CDRG) with a very small frequency split between two degenerate modes has been designed and implemented. In comparison with the ring-like DRG (RDRG), the CDRG has fewer fabrication imperfections owing to its all-linear structure. In addition, the CDRG displays a superior nonlinear effect compared with the RDRG, and internal differential electrode excitation and detection were used to further reduce the nonlinear effect. The CDRGs and RDRGs were placed side by side on the same wafer, and the characteristics of these as-fabricated resonators were then tested. The results showed that the resonant frequencies and Q-factors of the CDRGs and RDRGs were approximately 18 kHz and nearly 100k, respectively. The smallest as-fabricated relative frequency split (29.9 ppm) of the CDRGs was about 10.8 times smaller than that (322.5 ppm) of an RDRG built side by side on the same wafer, which had the lowest relative frequency split among all current disk resonator gyros. Finally, the preliminary results for the performance of the CDRG and RDRG in the force-to-rebalance mode and mode matching are given. Under the same conditions, the maximum vibration displacement, scale factor, angular random walk, and bias instability of the CDRG were improved by 62.8%, 112%, 700%, and 314%, respectively, compared with the RDRG.

Frequency symmetry of a cobweb-like disk resonator gyroscope (CDRG) has been compared with a conventional ring-like disk resonant gyroscope (RDRG) in this letter to corroborate that linear beam structures have a better process tolerance than curved beam structures for micro-fabrication processes. The CDRG comprises multiple concentric cobweb-like rings and each is formed by 16 identical straight beams joined end-to-end. It exhibits as-fabricated symmetric vibration behavior superior to RDRGs. To compare as-fabricated structural symmetry, CDRG and RDRG are placed side-by-side on the same wafer and simulated using COMSOL. A tested frequency split as low as 0.56 Hz is achieved for CDRG, and the average relative frequency split is 79.7 ppm, which is approximately seven times smaller than that of RDRG. Additionally, a temperature characteristics test demonstrates that the as-fabricated CDRG has excellent temperature stability, and the relative frequency split varied by 2.83 ppm in the temperature ranging from −20 °C to +80 °C. The proposed concept is verified by the simulation and experimental results.

Nondestructive tomographic identification of underlying moldy lesions of apple is demonstrated experimentally, for the first time, by using frequency domain diffuse optical tomography (FD-DOT). The custom applicator-probe had 18 optodes distributed on a spheroid apple-size imaging domain. The 12 source channels were time-multiplexed to a laser source modulated at 110 MHz, and the 6 detector channels were individually conditioned for parallel heterodyning at 10 kHz. The iterative image reconstruction was performed without priors in an open-source finite-element-method (FEM) package with custom meshing of the imaging domain. Cylindrical moldy lesions in apple at controlled center depths ranging from 10 mm to 35 mm were established using 10 mm diameter cylinder inclusions harvested from mildew flesh, and freeform lesions in apple were developed by injecting colonies of Alternaria alternate. The moldy lesions not deeper than 20 mm from the peel were resolvable on the absorption images. The moldy lesions were unremarkable on the reduced scattering images. Contrast-detail-analysis is also performed in simulation to assess the condition of identifying a moldy-core lesion by FD-DOT.

Overexpression of reactive oxygen species in the substantia nigra pars compacta destroys dopaminergic neurons and accelerates the pathological process of Parkinson's disease (PD). In this study, a new hydrophilic nano-bioconjugate, lactoferrin (Lf)-modified Au-Bi2 Se3 nanodot (ND) for efficient PD therapy is developed. In particular, the Lf-Au-Bi2 Se3 NDs exhibit strong blood-brain barrier (BBB) permeation. The Lf-Au-Bi2 Se3 NDs can also serve as multiple enzymes such as superoxide dismutase, catalase, glutathione peroxidase, and peroxide. These NDs are located close to the mitochondria and thus maintain the mitochondrial membrane potential as well as control the cellular ROS level. In vivo results further demonstrate that the NDs can improve the memory and mobility of PD mice; permeation of the BBB, protection of mitochondria, and suppression of dopaminergic neuron loss in the substantia nigra pars compacta are also observed. It is anticipated that these new Lf-Au-Bi2 Se3 NDs with excellent biocompatibility, multienzyme functionality, and BBB permeability will open new opportunities for PD therapy.

Based on the data of regional outcrop observation, high-precision 3-D seismic detection and wellbore rock-electricity, this paper researched macro-water distribution, seismic architecture of sedimentary-filling, rock composition, heavy mineral assemblage, and zircon age. The axial channel provenance system and accumulation of natural gas of the Upper Miocene Huangliu Formation in the Qiongdongnan Basin was analyzed. The research showed that axial channels deposits were provided with two depression stages, multiple provenances, and gravity flows by bottom current rework. Early channels sandstone with small size and formation overpressure was mainly from terrigenous material of southwest drainage system in Hainan uplift, while Qiupen River in the central Kunsong uplift was the primary provenance of late channels sandstone with large scale of sediments, good continuity and normal formation pressure. There are three types of axial channel sandstone traps: litho-stratigraphic, lithologic and tectono-stratigraphic trap. Natural gas of early channels was driven by deep overpressure and vertically migrated into reservoir along fissures, while natural gas of late channels lateral migrated from west to east. Key words: Qiongdongnan Basin, Miocene Huangliu Formation, axial channel, sediment characteristic, provenance system, gas accumulation

This paper presents an analytic, numerical and experimental study of air damping behavior of lateral-axis vibratory wheel gyroscopes (VWG) in vacuum range of 0.008Pa to 10Pa. An analytic model is proposed for slide film damping in drive mode, and a Reynolds equation solved by a finite-difference method is employed for squeeze film damping in sense mode. The developed models are verified by experiment results for a lateral-axis VWG with resonant frequency around 10kHz. It is the first time to find that in the lateral-axis VWG, with pressure decreasing, the main energy loss will transform from air damping to non-viscous energy dissipations (including thermal-elastic damping (TED), anchor loss, etc.) at the critical pressure points of 0.85Pa and 0.4Pa, in drive and sense modes respectively. The calculated Q-factors are within +/−15% of the measured value when non-viscous energy dissipation mechanisms are included.

Mobile cyber-physical systems (CPSs) are very hard to verify, because of asynchronous communication and the arbitrary number of components. Verification via model checking typically becomes impracticable due to the state space explosion caused by the system parameters and concurrency. In this paper, we propose a formal approach to verify the safety properties of parameterized protocols in mobile CPS. By using counter abstraction, the protocol is modeled as a Petri net. Then, a novel algorithm, which uses IC3 (the state-of-the-art model checking algorithm) as the back-end engine, is presented to verify the Petri net model. The experimental results show that our new approach can greatly scale the verification capabilities compared favorably against several recently published approaches. In addition to solving the instances fast, our method is significant for its lower memory consumption.