Research progress of out-of-plane GeSn nanowires

With the increasing integration density of silicon-based circuits, traditional electrical interconnections have shown their technological limitations. In recent years, GeSn materials have attracted great interest due to their potential direct bandgap transition and compatibility with silicon-based technologies. GeSn materials, including GeSn films, GeSn alloys, and GeSn nanowires, are adjustable, scalable, and compatible with silicon. GeSn nanowires, as one-dimensional (1D) nanomaterials, including out-of-plane GeSn nanowires and in-plane GeSn nanowires, have different properties from those of bulk materials due to their distinctive structures. However, the synthesis and potential applications of out of plane GeSn nanowires are rarely compared to highlighting their current development status and research trends in relevant review papers. In this article, we present the preparation of out-of-plane GeSn nanowires using top-down (etching and lithography) and bottom-up (vapor-liquid-solid) growth mechanism in the vapor-phase method and supercritical fluid-liquid-solid, solution-liquid-solid, and solvent vapor growth mechanisms in the liquid-phase method) methods. Specifically, the research progress on typical out of plane GeSn nanowires are discussed, while some current development bottlenecks are also been identified. Finally, it is also provided a brief description of the applications of out-of-plane GeSn nanowires with various Sn contents and morphologies.

Ultrasound-guided stellate ganglion blockade - patient positioning is everything: a case report demonstrating the efficacy of a modified out-of-plane approach

Background

Insomnia has become increasingly prevalent in modern society and is notoriously difficult to treat. Many patients exhibit a poor response to pharmacological interventions. Stellate ganglion block (SGB) has emerged as an effective method for managing insomnia; however, its efficacy may be compromised in some patients, primarily due to a variant vertebral artery anatomy.

Case presentation

This case report describes a patient with severe insomnia accompanied by anxiety. Through cervical ultrasound scanning, we identified richly branched cervical arteries at the C6-C7 segment of the vertebral artery, along with anatomical variations, which could pose a heightened risk for the traditional SGB procedure. Therefore, after carefully adjusting the patient's positioning, we proceeded with ultrasound-guided SGB using a lateral paravein out-of-plane approach. Clinical signs of successful insomnia symptoms alleviation were consistently observed after each block utilizing this alternative technique multiple times in a single patient.

Conclusion

Our report reveals a new lateral paravein out-of-plane approach for ultrasound-guided SGB to treat insomnia, which might be considered an alternative method. More studies should be carried out to confirm the efficacy of this new approach.

Comparison of novel anteroposterior short-axis in-plane technique with conventional short-axis out-of-plane technique for ultrasound-guided internal jugular vein cannulation: A randomized-controlled trial

OBJECTIVES

Various ultrasound (US)-guided probe positioning and needle procedures have been described in the literature for cannulation of the internal jugular vein (IJV). In the present study, we compared the conventional short-axis out-of-plane (SAX-OOP) method with a novel anteroposterior short-axis in-plane (APSAX-IP) technique for IJV cannulation under US guidance. The APSAX-IP method of IJV cannulation has not been compared to other IJV cannulation techniques.

METHODS

A total of 104 patients above 18-year-old were randomly allocated to one of two groups - APSAX-IP or SAX-OOP and evaluated for US-guided IJV cannulation in either the operating room or critical care unit. The primary outcome of this research was the access time for IJV cannulation using both approaches. The secondary outcomes were the number of attempts of needle insertion, success rate, and complications of IJV cannulation.

RESULTS

The access time for IJV cannulation was 13.0 (12.0-15.0) sec in the APSAX-IP group and 13.0 (12.0-14.0) sec in the SAX-OOP group; P = 0.947. The number of successful 1^st attempts was 90.91%, and the 2^nd attempts were 9.09% in the APSAX-IP group and 85.19% and 14.81% in the SAX-OOP group, respectively. Both techniques did not have any complications.

CONCLUSIONS

We conclude that the US-guided APSAX-IP IJV cannulation method has comparable access time to the SAX-OOP technique.

Out-of-Plane Behavior of Masonry Prisms Retrofitted with Shape Memory Alloy Stripes: Numerical and Parametric Analysis

This paper provides a novel Finite Element (FE) simulation to estimate the out-of-plane response of masonry prisms retrofitted with Shape Memory Alloy (SMA) stripes. Empirical data were utilized to develop the computational analysis parameters (mechanical parameters for brick, mortar, and SMA materials) as well as the calibration of the computational FE-based models. For this purpose, a complete micro-modeling approach was applied, assuming perfect contact between mortar joints and brick units. A Concrete Damage Plasticity (CDP) model was developed to define the constitutive relation between brick and mortar. SMA stripes were mortar-installed on the surface of the prisms with a perfect connection. The masonry prism's verified computational model was utilized to generate parametric research to explore the effect of varying SMA stripe thicknesses and different SMA usage (Ni-Ti or Cu-Zn-Al). The FE study findings indicated that, independent of their material type or thickness, using SMA stripes greatly minimizes brick prism deterioration. SMA stripes greatly decreased residual displacement and plastic strains. Parametric tests, however, revealed that employing Ni-Ti SMA and increasing its thickness is more effective with respect to the masonry prism out-of-plane response than Cu-Zn-Al SMA.

Exploring the Factors Affecting the Mechanical Properties of 2D Hybrid Organic-Inorganic Perovskites

Mechanical stability of hybrid organic-inorganic perovskites (HOIPs) is essential to achieve long-term durable HOIP-based devices. While HOIPs in two-dimensional (2D) form offer numerous options in the structure and composition to tune their mechanical properties, little is known about the structure-mechanical-property relationship in this family of materials. Here, we investigated a series of 2D lead halide HOIPs by nanoindentation to explore the impact of critical factors controlling the properties of both the organic and inorganic layers on the materials' out-of-plane mechanical performance. We find that the lead-halide bond in the inorganic framework can significantly influence the mechanical properties of 2D Ruddlesden-Popper (RP) HOIPs with n = 1. Like 3D HOIPs, stronger lead-halide bond strength leads to a higher Young's modulus in these 2D HOIPs, i.e., E_⊥^Cl ≳ E_⊥^Br > E_⊥^I. In contrast, the hardness of 2D RP HOIPs follows a trend of H_Br^2D > H_Cl^2D > H_I^2D, which is different from that found in 3D HOIPs, probably due to the combined effects from the Pb-X bond strength and inorganic framework structural change (e.g., symmetry and distortion). We further show that the interface between the organic layers in 2D HOIPs can be an effective route to engineer the materials' mechanical properties. Replacing the weak CH₃-CH₃ van der Waals forces by covalent bonds or phenyl-phenyl interactions in the interface can lead to a much stiffer and harder 2D HOIPs. Finally, we discover that the mechanical performance of 2D HOIPs with linear aliphatic diammonium spacer molecules is affected by the two basic structural parameters, i.e., the thicknesses of the organic and inorganic layers, in a similar way compared to that of 2D RP HOIPs with linear aliphatic monoammonium spacer molecules. A thinner organic layer and a thicker inorganic layer can result in 2D HOIPs with larger elastic modulus and hardness values. Our results offer intriguing insights into the structure-property relationship of 2D HOIPs from a mechanical perspective, providing guidelines and inspirations to achieve material design with required mechanical properties for applications.

Microinjection Molding of Out-of-Plane Bistable Mechanisms

We present a novel fabrication technique of a miniaturized out-of-plane compliant bistable mechanism (OBM) by microinjection molding (MM) and assembling. OBMs are mostly in-plane monolithic devices containing delicate elastic elements fabricated in metal, plastic, or by a microelectromechanical system (MEMS) process. The proposed technique is based on stacking two out-of-plane V-beam structures obtained by mold fabrication and MM of thermoplastic polyacetal resin (POM) and joining their centers and outer frames to construct a double V-beam structure. A copper alloy mold insert was machined with the sectional dimensions of the V-beam cavities. Next, the insert was re-machined to reduce dimensional errors caused by part shrinkage. The V-beam structure was injection-molded at a high temperature. Gradually elongated short-shots were obtained by increasing pressure, showing the symmetrical melt filling through the V-beam cavities. The as-molded structure was buckled elastically by an external-force load but showed a monostable behavior because of a higher unconstrained buckling mode. The double V-beam device assembled with two single-molded structures shows clear bistability. The experimental force-displacement curve of the molded structure is presented for examination. This work can potentially contribute to the fabrication of architected materials with periodic assembly of the plastic bistable mechanism for diverse functionalities, such as energy absorption and shape morphing.

Flexible Out-of-Plane Wind Sensors with a Self-Powered Feature Inspired by Fine Hairs of the Spider

The quest for out-of-plane and self-powered wind sensors has motivated the field of outdoor sports, exploration, space perception, and positioning. Fine hairs of spiders act as hundreds of individual wind sensors, allowing them to feel the nearby wind change caused by the predators or the prey. Inspired by this natural teacher, here, we demonstrate the fabrication of bioinspired self-powered out-of-plane wind sensors based on flexible magnetoelectric material systems. The shape of flexible sensors, by patterning silver nanoparticles on a thin polyethylene terephthalate film through a screen printing technique, mimics fine hairs of the spiders, allowing for out-of-plane tactile perceptual monitoring caused by the wind. Owing to the employment of flexible magnetoelectric materials, the sensors can distinguish forward/backward winds and are totally self-powered. The working mechanism for sensors has been explained by the Maxwell numerical simulation, allowing for further improvement of their performance by tuning diverse factors. Furthermore, the wind sensor can detect the wind with a velocity down to 1.2 m/s and distinguish multidegree wind by their arrays. It is expected that, in the near future, our design can provide new findings for out-of-plane wind sensors with superior self-powered properties toward new flexible electronics.

Measurement of Three-Dimensional Structural Displacement Using a Hybrid Inertial Vision-Based System

Accurate three-dimensional displacement measurements of bridges and other structures have received significant attention in recent years. The main challenges of such measurements include the cost and the need for a scalable array of instrumentation. This paper presents a novel Hybrid Inertial Vision-Based Displacement Measurement (HIVBDM) system that can measure three-dimensional structural displacements by using a monocular charge-coupled device (CCD) camera, a stationary calibration target, and an attached tilt sensor. The HIVBDM system does not require the camera to be stationary during the measurements, while the camera movements, i.e., rotations and translations, during the measurement process are compensated by using a stationary calibration target in the field of view (FOV) of the camera. An attached tilt sensor is further used to refine the camera movement compensation, and better infers the global three-dimensional structural displacements. This HIVBDM system is evaluated on both short-term and long-term synthetic static structural displacements, which are conducted in an indoor simulated experimental environment. In the experiments, at a 9.75 m operating distance between the monitoring camera and the structure that is being monitored, the proposed HIVBDM system achieves an average of 1.440 mm Root Mean Square Error (RMSE) on the in-plane structural translations and an average of 2.904 mm RMSE on the out-of-plane structural translations.

Unified Theory for Flexural Strengthening of Masonry with Composites

Recent calamitous events have shown the fragility of the existing masonry buildings. Many of them are heritage structures, such as churches and monumental buildings. Therefore, optimized strengthening strategies are necessary. Experimental studies performed on masonry elements strengthened with composite systems have shown the performance of these materials. However, further development is necessary to optimize the intervention strategies. In fact, due to the lack of general validity models, the design is usually based on prescriptive approaches according to manufacturers' broad instructions, often producing systems with low efficiency and overestimations of the amount of reinforcement. In this paper a generalized approach is proposed to assess the flexural behavior of masonry sections strengthened with composites. The proposed theory has allowed performance of a sensitivity analysis assessing the impact both of the mechanical parameters of masonry and of the strengthening system. In particular, the impact of several constitutive relationships of composites (linear, bilinear, or trilinear) have been evaluated in terms of ultimate behavior of the strengthened masonry. For strengthening systems more compatible with the masonry substrate, the form of the stress⁻strain relationship becomes a key aspect. For such cases, the modeling of the reinforcement plays a fundamental role and the form of the relationship is strongly correlated to the type of reinforcement selected, e.g., organic versus inorganic matrix.

A Geometrical Study on the Roof Tile-Shaped Modes in AlN-Based Piezoelectric Microcantilevers as Viscosity⁻Density Sensors

Cantilever resonators based on the roof tile-shaped modes have recently demonstrated their suitability for liquid media monitoring applications. The early studies have shown that certain combinations of dimensions and order of the mode can maximize the Q-factor, what might suggest a competition between two mechanisms of losses with different geometrical dependence. To provide more insight, a comprehensive study of the Q-factor and the resonant frequency of these modes in microcantilever resonators with lengths and widths between 250 and 3000 µm and thicknesses between 10 and 60 µm is presented. These modes can be efficiently excited by a thin piezoelectric AlN film and a properly designed top electrode layout. The electrical and optical characterization of the resonators are performed in liquid media and then their performance is evaluated in terms of quality factor and resonant frequency. A quality factor as high as 140 was measured in isopropanol for a 1000 × 900 × 10 µm³ cantilever oscillating in the 11th order roof tile-shaped mode at 4 MHz; density and viscosity resolutions of 10⁻⁶ g/mL and 10⁻⁴ mPa·s, respectively are estimated for a geometrically optimized cantilever resonating below 1 MHz.

Out-of-Plane Ionic Conductivity Measurement Configuration for High-Throughput Experiments

An approach for measuring conductivity of thin-film electrolytes in an out-of-plane configuration, amenable to high-throughput experimentation, is presented. A comprehensive analysis of the geometric requirements for success is performed. Using samaria-doped ceria (Ce_0.8Sm_0.2O_1.9, SDC) excellent agreement between bulk samples and thin films with continuous and patterned electrodes, 100-500 μm in diameter, is demonstrated. Films were deposited on conductive Nb-doped SrTiO₃, and conductivity was measured by AC impedance spectroscopy over the temperature range from ∼200 to ∼500 °C. The patterned electrode geometry, which encompassed an array of microdot metal electrodes for making top contact, enabled measurements at hundreds of positions on the film, implying the potential for measuring hundreds of composition in a single library.

Out-of-Plane Mechanical Properties of 2D Hybrid Organic-Inorganic Perovskites by Nanoindentation

Two-dimensional (2D) layered hybrid organic-inorganic perovskites (HOIPs) have demonstrated improved stability and promising photovoltaic performance. The mechanical properties of such functional materials are both fundamentally and practically important to achieve both high performance and mechanically stable (flexible) devices. Here, we report the mechanical properties of a series of 2D layered lead iodide HOIPs and investigate the role of structural subunits (e.g., variation of the length of the organic spacer molecules, R and the number of inorganic layers, n) in the mechanical properties. Although 2D HOIPs have much lower nominal elastic modulus and hardness than 3D HOIPs, larger n number and shorter R lead to stiffer materials. Density functional theory simulations showed a trend similar to the experimental results. We compared these findings with other 2D layered crystals and shed light on routes to further tune the out-of-plane mechanical properties of 2D layered HOIPs.

Out-of-Plane Continuous Electrostatic Micro-Power Generators

This paper presents an out-of-plane electrostatic micro-power generator (MPG). Electret-based continuous MPGs with different gaps and masses are fabricated to demonstrate the merits of this topology. Experimental results of the MPG demonstrate output power of 1 mW for a base acceleration amplitude and frequency of 0.08 g and 86 Hz. The MPGs also demonstrate a wideband harvesting bandwidth reaching up to 9 Hz. A free-flight and an impact mode model of electrostatic MPGs are also derived and validated by comparison to experimental results.

A new approach for optical assessment of directional anisotropy in turbid media

A study of polarized light transport in scattering media exhibiting directional anisotropy or linear birefringence is presented in this paper. Novel theoretical and experimental methodologies for the quantification of birefringent alignment based on out-of-plane polarized light transport are presented here. A polarized Monte Carlo model and a polarimetric imaging system were devised to predict and measure the impact of birefringence on an impinging linearly polarized light beam. Ex-vivo experiments conducted on bovine tendon, a biological sample consisting of highly packed type I collagen fibers with birefringent property, showed good agreement with the analytical results.

Dynamic sensing performance of a point-wise fiber Bragg grating displacement measurement system integrated in an active structural control system

In this work, a fiber Bragg grating (FBG) sensing system which can measure the transient response of out-of-plane point-wise displacement responses is set up on a smart cantilever beam and the feasibility of its use as a feedback sensor in an active structural control system is studied experimentally. An FBG filter is employed in the proposed fiber sensing system to dynamically demodulate the responses obtained by the FBG displacement sensor with high sensitivity. For comparison, a laser Doppler vibrometer (LDV) is utilized simultaneously to verify displacement detection ability of the FBG sensing system. An optical full-field measurement technique called amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) is used to provide full-field vibration mode shapes and resonant frequencies. To verify the dynamic demodulation performance of the FBG filter, a traditional FBG strain sensor calibrated with a strain gauge is first employed to measure the dynamic strain of impact-induced vibrations. Then, system identification of the smart cantilever beam is performed by FBG strain and displacement sensors. Finally, by employing a velocity feedback control algorithm, the feasibility of integrating the proposed FBG displacement sensing system in a collocated feedback system is investigated and excellent dynamic feedback performance is demonstrated. In conclusion, our experiments show that the FBG sensor is capable of performing dynamic displacement feedback and/or strain measurements with high sensitivity and resolution.