Atomic Layer Deposition of Metal Oxides and Chalcogenides for High Performance Transistors

Atomic layer deposition (ALD) is a deposition technique well-suited to produce high-quality thin film materials at the nanoscale for applications in transistors. This review comprehensively describes the latest developments in ALD of metal oxides (MOs) and chalcogenides with tunable bandgaps, compositions, and nanostructures for the fabrication of high-performance field-effect transistors. By ALD various n-type and p-type MOs, including binary and multinary semiconductors, can be deposited and applied as channel materials, transparent electrodes, or electrode interlayers for improving charge-transport and switching properties of transistors. On the other hand, MO insulators by ALD are applied as dielectrics or protecting/encapsulating layers for enhancing device performance and stability. Metal chalcogenide semiconductors and their heterostructures made by ALD have shown great promise as novel building blocks to fabricate single channel or heterojunction materials in transistors. By correlating the device performance to the structural and chemical properties of the ALD materials, clear structure–property relations can be proposed, which can help to design better-performing transistors. Finally, a brief concluding remark on these ALD materials and devices is presented, with insights into upcoming opportunities and challenges for future electronics and integrated applications

A Wideband Coaxial-to-Ridge waveguide Adaptor

A Coaxial-to-ridge waveguide adaptor covering the entire K and Ka band has been demonstrated in this article. The adaptor is in the form of asymmetric double ridge waveguides and characteristic impedances of each step is determined by Chebyshev polynomial. A new method of calculating the characteristic impedance of the asymmetric double ridge waveguide is presented and the wideband adaptor is designed on this basis. The simulated results for the proposed adaptor in HFSS show that the return loss is better than 17.8dB in the entire K and Ka band and the insertion loss is better than 0.1dB. The simulated results for the back-to-back confi guration show that return loss is better than 15 dB and insertion loss is better than 0.2dB. To demonstrate its performance, the adaptor is fabricated and then measured on the vector network analyser. The measured results show that the average insertion loss of the adaptor is about 1dB in the whole band

Synthesis and kinetic analysis of hydromagnesite with different morphologies by nesquehonite method

514-521Hydromagnesite with different morphologies has been synthesized using self-made nesquehonite whiskers as raw materials. The synthesized samples have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that porous rod-like hydromagnesite are generated at 328~353K and in the pH value of 9.30+0.2, while irregular flower-like and flat layered ones are synthesized in the pH values of 10.0+0.05 and 11.0+0.05, respectively. The yield of hydromagnesite improved linearly with the increase of the temperatures and solution pH values. Porous rod-like hydromagneiste crystals with good crystalline and uniform morphology are obtained when the pyrolysis time is over 60 min. Furthermore, the apparent activation energy of phase transformation is calculated to be 3.4080 kJ/mol. According to the results, the experimental data can be well described by the kinetic model, suggesting that the phase transfer rate is dependent on the temperature

High-Directivity Antenna Array Based on Artificial Electromagnetic Metamaterials with Low Refractive Index

Planar metamaterials (MTMs) with low refractive index are proposed as a cover in a high-gain patch antenna array configuration. This MTMs array antenna has the following features: the number of array elements significantly decreases compared with the conventional array; the elements spacing is larger than a wave length by far; the feeding network is simpler. MTMs are made of two layers of periodic square metallic grids and placed above the feeding array. With the same aperture size, the directivity of MTMs-cover antenna array is higher than the conventional antenna array. The simulation results show that an array of 2 × 2 patch elements integrated with MTMs yields about 26 dB of directivity which is higher than that of conventional 8 × 8 patch array. Furthermore, on the condition of the same aperture size, an array patch with 4 × 4 elements integrated with the MTMs-cover has an equivalent gain compared with the conventional patch array with 16 × 16 array elements. Obviously, the former has a simpler feeding network and higher aperture efficiency. The experimental work has verified that the 2 × 2 array case and the measured results have good agreement with the simulation

Ghrelin contributes to protection of hepatocellular injury induced by ischaemia/reperfusion

Background & Aims Ghrelin, a gut hormone with pleiotropic effects, may act as a protective signal in parenchymal cells. We investigated the protective effects of ghrelin on hepatocytes after ischaemia/reperfusion (I/R). Methods Hepatic injury was assessed by measurement of plasma alanine aminotransferase ( ALT ) and lactate dehydrogenase ( LDH ), histological analysis, and TUNEL assay. Effects of exogenous ghrelin and ghrelin receptor gene deletion on I/R induced injury of liver were evaluated. Results Ischaemia/reperfusion induced a profound injury to hepatocytes. This was accompanied by elevations in plasma ALT and LDH . Pretreatment with ghrelin significantly reduced elevations in plasma ALT and LDH , and attenuated tissue damage induced by hepatic I/R in mice. Hepatic injury induced by I/R was more pronounced in ghrelin receptor gene null mice. Ghrelin administration blocked the up‐regulation of AMP ‐activated protein kinase ( AMPK ) activity induced by hepatic I/R. Conclusions This study demonstrates that ghrelin contributes to the cytoprotection during hepatic I/R.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106759/1/liv12286.pd

HIPPO: Pervasive Hand-Grip Estimation from Everyday Interactions

Hand-grip strength is widely used to estimate muscle strength and it serves as a general indicator of the overall health of a person, particularly in aging adults. Hand-grip strength is typically estimated using dynamometers or specialized force resistant pressure sensors embedded onto objects. Both of these solutions require the user to interact with a dedicated measurement device which unnecessarily restricts the contexts where estimates are acquired. We contribute HIPPO, a novel non-intrusive and opportunistic method for estimating hand-grip strength from everyday interactions with objects. HIPPO re-purposes light sensors available in wearables (e.g., rings or gloves) to capture changes in light reflectivity when people interact with objects. This allows HIPPO to non-intrusively piggyback everyday interactions for health information without affecting the user's everyday routines. We present two prototypes integrating HIPPO, an early smart glove proof-of-concept, and a further optimized solution that uses sensors integrated onto a ring. We validate HIPPO through extensive experiments and compare HIPPO against three baselines, including a clinical dynamometer. Our results show that HIPPO operates robustly across a wide range of everyday objects, and participants. The force strength estimates correlate with estimates produced by pressure-based devices, and can also determine the correct hand grip strength category with up to 86\% accuracy. Our findings also suggest that users prefer our approach to existing solutions as HIPPO blends the estimation with everyday interactions.Peer reviewe

The apparent focal depth, emergence angle, and take-off angle of seismic wave measured by YRY-4-type borehole strainmeter as one kind of strain seismograph

Introduction: In theory, the observation objects and principles of strain seismograph and traditional pendulum seismograph are different, and the characteristics of observed signals should also be dissimilar. The observation results of pendulum seismograph show that seismic waves in inhomogeneous media will undergo refraction, reflection, and attenuation. Then, what signal characteristics can be detected by strain seismograph is great significance for understanding and explaining the observation results.Methods: Using YRY-4 type four-gauge borehole strainmeter as one kind of strain seismograph to detect the strain tensor change of the plane seismic wave emitted from the surface, a five-site strain seismograph observation network was built in Shanxi Province, with continuous observation for 2 years at a sampling rate of 100 Hz. In this paper, two local events occurring in the area covered by the strain seismograph observation network are taken as examples. We systematically studied the characteristics of seismic wave signals recorded by strain seismographs at five sites, inverted for the focal depth of the two local earthquakes and the relationship between the wave velocity and the wave velocity gradient of the focal depth, and calculated the apparent focal depth, the emergence angle and the take-off angle of seismic waves.Results: These results show stable uniqueness and apparent regularity, especially since the inverted focal depths are basically consistent with the seismic solutions based on those traditional pendulum seismographs. The observations from this study show that the strain seismograph can be used as an effective supplement to the pendulum seismograph.Discussion: In the future, we will continue to study the rupture process and focal mechanism of moderate-strong earthquakes and teleseismic earthquakes by combining two kinds of observations