Search

A system for the investigation of the magnetic properties of materials under high pressure is fabricated based on diamond anvil cell (DAC) technology. The system is designed with an improved coil arranged around the diamond of a non-magnetic DAC. Using this system, the magnetic transition of ferromagnetic (Fe) sample under increasing pressure can be observed. We successfully obtain the evolution of magnetic properties as a function of applied pressure reaching 26.9 GPa in the Fe sample. A magnetic transition is observed at approximately 13 GPa, which is consistent with the theoretical prediction. [ABSTRACT FROM AUTHOR]

Flexible pressure sensing plays a critical role in the human–machine interaction; therefore highly sensitive pressure sensors have promising potential in such applications. Capacitive pressure sensors have inherent attributes of simple configuration and fast response time. However, the existing applications of sensors are limited by the limited sensitivity as well as complex manufacturing. Herein, a highly sensitive ionic pressure sensor with the microstructured dielectric layer has been proposed. The polycarbonate membrane is used as the template to manufacture the microstructure of the concave meniscus. By packing the top electrode, dielectric layer and bottom electrode, the ionic pressure sensor is fabricated. The sensor presents a sensitivity of 35.96 k Pa−1 with an excellent robustness of tolerating repeated pressure for at least 200 000 cycles without fatigue. In addition, the response time of the sensor is 21 ms and the limit of detection is 0.61 Pa. The ionic pressure sensor offers a highly sensitive sensing device for robotics and human–machine interaction. Furthermore, the concave meniscus realized by the template-based method provides a novel guideline for other microstructure-enabled devices. [ABSTRACT FROM AUTHOR]

We present a novel Cu-metal-organic framework (MOF) with two-dimensional layered topology and techniques to integrate it with flexible sensors for electrochemical detection. The unique Cu-MOF is formed by coordinating Cu2+ ions with carboxylic oxygen groups, resulting in layered structures interlayerly connected by hydrogen bonds. The resulting flexible sensors exhibit capability in detecting ascorbic acid (AA), hydrogen peroxide (H2O2) and L-Histidine (L-His) with detection limits of 2.94, 4.1 and 5.3 μM, respectively. The linear ranges of the sensors compare favorably with other sensors based on rigid platforms that offer similar sensitivity. According to the result of cytotoxicity study, the MOFs-modified flexible sensors exhibit good biocompatibility to cells, suggesting potential use in in vivo chemical detection. The results presented here demonstrate applications of MOFs in facilitating highly stable electrochemical detection in flexible electronics, and provide fundamental knowledge about structure-dependent electrochemical properties of MOFs and changing behaviors of flexible MOFs membranes under external strain. More MOFs-based flexible sensors may be developed to explore different properties of MOFs by varying their compositions and structures for healthcare and clinic applications. [ABSTRACT FROM AUTHOR]

In this paper, a novel current–time model of anodic bonding is proposed and verified experimentally in order to investigate underlying mechanisms of anodic bonding and to achieve real-time monitoring of bonding procedure. The proposed model provides a thorough explanation for the electric current characteristic of anodic bonding. More significantly, it explains two issues which other models cannot explain. One is the sharp rise in current when a voltage is initially applied during anodic bonding. The other is the unexpected large width of depletion layers. In addition, enlargement of the intimately contacted area during anodic bonding can be obtained from the proposed model, which can be utilized to monitor the bonding process. To verify the proposed model, Borofloat33 glass and silicon wafers were adopted in bonding experiments in SUSS SB6 with five different bonding conditions (350 °C 1200 V; 370 °C 1200 V; 380 °C 1200 V; 380 °C 1000 V; and 380 °C 1400 V). The results indicate that the observed current data highly coincide with the proposed current-time model. For widths of depletion layers, depth profiling using secondary ion mass spectrometry demonstrates that the calculated values by the model are basically consistent with the experimental values as well. [ABSTRACT FROM AUTHOR]

In this study, a one-step method of fabricating nano to micro structures was reported. Monte Carlo (MC) simulation and a fluid equation were employed to study the formation and evolution mechanism. To verify the fundamental simulation and hypothetical mechanism, standard surface technology (STS) was used with a phase delay producer to build the etching system. Also, throughout the practical experiment, the relationship between the structure scale and the process parameter was recorded. Lastly, the reflectance was measured to be only 0.9%, proving that this method was very promising for optical application. [ABSTRACT FROM AUTHOR]

Nested folded-beam suspensions with a low longitudinal spring constant and a high lateral spring constant have been used in comb-drive actuators. In the new design, every two flexible beams and two stiff members form a parallelogram flexure, which is considered as an ‘element’ of the nested folded-beam suspension. A set of these flexures of increasing size were placed one outside another to compose a nested structure. In this way, a serial mechanical connection between adjacent parallelogram flexures was formed; thus, a longer output stroke was obtained by combining the stroke displacements of all flexures in an additive fashion. The designed suspensions were theoretically analyzed and numerically simulated. Furthermore, comb-drive actuators with conventional and new suspensions were fabricated and tested to verify the predicted function. In the testing cases, the longitudinal spring constants of suspensions with two (conventional), three and four parallelogram flexures on each side were measured as 2.77, 1.75 and 1.36 N m−1. The ratio among these three values was approximately 6:4:3, which is consistent with the theoretical predictions and simulation results. Microfabricated folded beams in series were achieved. [ABSTRACT FROM AUTHOR]