Research on the Application of Microcast Electromagnetic Coil in an Si MEMS Bistable Recoverable Safety and Arming Device.

A low-driving energy and bistable recoverable MEMS safety and arming device (S&A), based on microcasting technology and deep silicon etching technology, is proposed to meet safety system requirements. A force-electromagnetic combination solution is constructed for the Si MEMS S&A, with parameters and strength verified, ultimately achieving an S&A size of (13 × 13 × 0.4) mm. Additionally, a low-driving energy U-shaped electromagnetic coil (USEC) model is designed using microcasting technology, and an electrical-magnetic-mechanical coupling mathematical model is established to explore the relationship between design parameters and driving capacity and reliability. With a driving power of 8 V/0.5 A, the model achieves a stable electromagnetic driving force of 15 mN with a travel distance of 0.5 mm. Finally, the fabrication and testing of the USEC and S&A are carried out, with driving capability and S&A disarming ability tests conducted to verify the feasibility of the system design. Compared to the existing S&A, this scheme has the advantages of low-driving energy, recoverability, fast response speed, and strong adaptability.

A High-Functional-Density Integrated Inertial Switch for Super-Quick Initiation and Reliable Self-Destruction of a Small-Caliber Projectile Fuze.

With the aim of achieving the combat technical requirements of super-quick (SQ) initiation and reliable self-destruction (SD) of a small-caliber projectile fuze, this paper describes a high-functional-density integrated (HFDI) inertial switch based on the "ON-OFF" state transition (i.e., almost no terminal ballistic motion). The reliable state switching of the HFDI inertial switch is studied via elastic-plastic mechanics and verified via both simulations and experiments. The theoretical and simulation results indicate that the designed switch can achieve the "OFF-ON" state transition in the internal ballistic system, and the switch can achieve the "ON-OFF" state transition in the simulated terminal ballistic system within 8 µs or complete the "ON-OFF" state transition as the rotary speed sharply decreases. The experimental results based on the anti-target method show the switch achieves the "ON-OFF" state transition on the µs scale, which is consistent with the simulation results. Compared with the switches currently used in small-caliber projectile fuzes, the HFDI inertial switch integrates more functions and reduces the height by about 44%.

Convolution Neural Network with Coordinate Attention for Real-Time Wound Segmentation and Automatic Wound Assessment.

BACKGROUND: Wound treatment in emergency care requires the rapid assessment of wound size by medical staff. Limited medical resources and the empirical assessment of wounds can delay the treatment of patients, and manual contact measurement methods are often inaccurate and susceptible to wound infection. This study aimed to prepare an Automatic Wound Segmentation Assessment (AWSA) framework for real-time wound segmentation and automatic wound region estimation. METHODS: This method comprised a short-term dense concatenate classification network (STDC-Net) as the backbone, realizing a segmentation accuracy-prediction speed trade-off. A coordinated attention mechanism was introduced to further improve the network segmentation performance. A functional relationship model between prior graphics pixels and shooting heights was constructed to achieve wound area measurement. Finally, extensive experiments on two types of wound datasets were conducted. RESULTS: The experimental results showed that real-time AWSA outperformed state-of-the-art methods such as mAP, mIoU, recall, and dice score. The AUC value, which reflected the comprehensive segmentation ability, also reached the highest level of about 99.5%. The FPS values of our proposed segmentation method in the two datasets were 100.08 and 102.11, respectively, which were about 42% higher than those of the second-ranked method, reflecting better real-time performance. Moreover, real-time AWSA could automatically estimate the wound area in square centimeters with a relative error of only about 3.1%. CONCLUSION: The real-time AWSA method used the STDC-Net classification network as its backbone and improved the network processing speed while accurately segmenting the wound, realizing a segmentation accuracy-prediction speed trade-off.

Research on Energetic Micro-Self-Destruction Devices with Fast Responses.

Information self-destruction devices represent the last protective net available to realize information security. The self-destruction device proposed here can generate GPa-level detonation waves through the explosion of energetic materials and these waves can cause irreversible damage to information storage chips. A self-destruction model consisting of three types of nichrome (Ni-Cr) bridge initiators with copper azide explosive elements was first established. The output energy of the self-destruction device and the electrical explosion delay time were obtained using an electrical explosion test system. The relationships between the different copper azide dosages and the assembly gap between the explosive and the target chip with the detonation wave pressure were obtained using LS-DYNA software. The detonation wave pressure can reach 3.4 GPa when the dosage is 0.4 mg and the assembly gap is 0.1 mm, and this pressure can cause damage to the target chip. The response time of the energetic micro self-destruction device was subsequently measured to be 23.65 µs using an optical probe. In summary, the micro-self-destruction device proposed in this paper offers advantages that include low structural size, fast self-destruction response times, and high energy-conversion ability, and it has strong application prospects in the information security protection field.

Research on MEMS Solid-State Fuse Logic Control Chip Based on Electrical Explosion Effect.

A microelectromechanical systems (MEMS) solid-state logic control chip with three layers-diversion layer, control layer, and substrate layer-is designed to satisfy fuse miniaturization and integration requirements. A mathematical model is established according to the heat conduction equation, and the limit conditions of different structures are presented. The finite element multi-physical field simulation method is used to simulate the size and the action voltage of the diversion layer of the control chip. Based on the surface silicon process, fuse processing, and testing with the MEMS solid-state fuse-logic control chip, a diversion layer constant current, maximum current resistance test, and a control layer of different bridge area sizes, the bridge area size is 200 × 30 µm, and the minimum electrical explosion voltage is 23.6 V. The theoretical calculation results at 20 V and 100 µF demonstrate that the capacitor energy is insufficient to support the complete vaporization of the bridge area, but can be partially vaporized, consistent with the experimental results.

Information self-destruction module design based on micro thermoelectric power generation and energetic materials.

Information self-destruction modules (ISDMs) play a vital role in the information security area. In this paper, an ISDM based on the integration of a micro-thermoelectric generation mechanism (M-TEGM) with energetic materials (EMs) is proposed. On the basis of energy conversion relationship, an open-loop electromotive force is induced, and this energy will drive the EMs to release the detonation wave and realize information storage module self-destruction. During the tests, under the temperature difference (100 K), the open-loop electromotive force (3.86 V) is induced by the M-TEGM and can drive the EMs (0.37 mg copper azide) to generate a detonation wave (GPa) in 3.4 µs, which can physically destroy the information storage modules. This ISDM has advantages that include rapid response times, low drive energy compared with traditional information security technology.

A microexplosive shockwave-based drug delivery microsystem for treating hard-to-reach areas in the human body.

Implantable drug-delivery microsystems have the capacity to locally meet therapeutic requirements by maximizing local drug efficacy and minimizing potential side effects. The internal organs of the human body including the esophagus, gastrointestinal tract, and respiratory tract, with anfractuos contours, all manifest with endoluminal lesions often located in a curved or zigzag area. The ability of localized drug delivery for these organs using existing therapeutic modalities is limited. Spraying a drug onto these areas and using the adhesion and water absorption properties of the drug powder to attach to lesion areas can provide effective treatment. This study aimed to report the development and application of microsystems based on microshockwave delivery of drugs. The devices comprised a warhead-like shell with a powder placed at the head of the device and a flexible rod that could be inserted at the tail. These devices had the capacity to deposit drugs on mucous membranes in curved or zigzag areas of organs in the body. The explosive impact characteristics of the device during drug delivery were analyzed by numerical simulation. In the experiment of drug delivery in pig intestines, we described the biosafety and drug delivery capacity of the system. We anticipate that such microsystems could be applied to a range of endoluminal diseases in curved or zigzag regions of the human body while maximizing the on-target effects of drugs.

Research on Insurance Method for Energetic Materials on Information Self-Destruction Chips.

Detonation waves released by energetic materials provide an important means of physical self-destruction (Psd) for information storage chips (ISCs) in the information insurance field and offer advantages that include a rapid response and low driving energy. The high electrical sensitivity of energetic materials means that they are easily triggered by leakage currents and electrostatic forces. Therefore, a Psd module based on a graphene-based insurance actuator heterogeneously integrated with energetic materials is proposed. First, the force-balance relation between the electrostatic van der Waals force and the elastic recovery force of the insurance actuator's graphene electrode is established to realize physical isolation and an electrical interconnection between the energetic materials and the peripheral electrical systems. Second, a numerical analysis of the detonation wave stress of the energetic materials in the air domain is performed, and the copper azide dosage required to achieve reliable ISC Psd is obtained. Third, the insurance actuator is prepared via graphene thin film processing and copper azide is prepared via an in situ reaction. The experimental results show that the energetic materials proposed can release physical isolation within 14 µs and can achieve ISC Psd under the application of a voltage signal (4.4-4.65 V). Copper azide (0.45-0.52 mg) can achieve physical damage over an ISC area (23.37-35.84 mm2) within an assembly gap (0.05-0.25 mm) between copper azide and ISC. The proposed method has high applicability for information insurance.

Study on Characteristics of Electromagnetic Coil Used in MEMS Safety and Arming Device.

Traditional silicon-based micro-electro-mechanical system (MEMS) safety and arming devices, such as electro-thermal and electrostatically driven MEMS safety and arming devices, experience problems of high insecurity and require high voltage drive. For the current electromagnetic drive mode, the electromagnetic drive device is too large to be integrated. In order to address this problem, we present a new micro electromagnetically driven MEMS safety and arming device, in which the electromagnetic coil is small in size, with a large electromagnetic force. We firstly designed and calculated the geometric structure of the electromagnetic coil, and analyzed the model using COMSOL multiphysics field simulation software. The resulting error between the theoretical calculation and the simulation of the mechanical and electrical properties of the electromagnetic coil was less than 2% under the same size. We then carried out a parametric simulation of the electromagnetic coil, and combined it with the actual processing capacity to obtain the optimized structure of the electromagnetic coil. Finally, the electromagnetic coil was processed by deep silicon etching and the MEMS casting process. The actual electromagnetic force of the electromagnetic coil was measured on a micro-mechanical test system, compared with the simulation, and the comparison results were analyzed.

Explosion Suppression Mechanism Characteristics of MEMS S&A Device With In Situ Synthetic Primer.

The traditional silicon-based micro-electro-mechanical systems (MEMS) safety and arming (S&A) device fuze cannot isolate abnormal outputs in the detonation environment, which creates hazards for personnel. To address this problem, we report the design of a MEMS S&A device with integrated silver, copper, nickel and polyimide (PI) films, which is based on the principle of a MEMS S&A device and uses copper azide as the primer. The MEMS S&A device was optimized using theoretical calculations of the explosion suppression mechanism performance in a detonation field, where the theoretical model was verified by dynamic simulation (LS-Dyna). Silicon-based MEMS processing technology was used to integrate the MEMS S&A device with energy-absorbing materials, and the device performance was compared in detonation tests. Silicon-based MEMS S&A devices with silver, copper, nickel, and PI (100-µm-thick) achieved a reliable explosion suppression mechanism capability when exposed to a detonation wave. The residual stress was measured using Raman microscopy, and the PI film exhibited the best explosion suppression mechanism performance of the four materials. A reliability test to determine the maximum explosion suppression mechanism dose for a MEMS S&A device attached to a PI film (100-µm-thick) showed that the maximum amount of primer needed for the effective explosion suppression mechanism capability on the MEMS S&A device was 0.45 mg.

Design of High-Reliability Micro Safety and Arming Devices for a Small Caliber Projectile.

With the development of micro technology, the fuse for small-caliber projectiles tends to be miniaturized and intelligent, the traditional fuse no longer meets the requirements. In this paper, we demonstrate a micro safety and arming (S & A) device with small volume and high reliability in small caliber projectile platforms. The working principle of S & A devices is that a centrifugal insurance mechanism could deform under a centrifugal load and thus cause fuse safety arming. The centrifugal insurance mechanism is designed theoretically, verified by simulation and experimental methods. The experimental results show that, when the rotary speed is over 36,000 rpm, the fuse was armed safely. In addition, the experimental, simulation, and theoretical results are basically consistent, and indicate that the centrifugal insurance mechanism meets the expected criteria.