Micro-EDM (Electrical Discharge Machining) finds extensive applications in the machining of micro-holes and fine features. However, the challenging removal of debris severely limits the machining of micro-holes with large depth-to-diameter ratios. The motion of bubbles generated during electrical discharge machining is considered a key factor influencing debris removal. This study explores the dynamic behavior of individual bubbles produced by single pulse discharge in micro-EDM. High-speed camera was employed to capture the effects of different discharge energies and machining polarity on bubble behavior. Experimental results reveal that machining with negative polarity significantly prolongs the duration of the arc plasma compared to positive polarity machining. Even after the discharge pulse ends, the plasma does not extinguish immediately but persists for a certain duration. Additionally, the final equilibrium diameter of the bubble is positively correlated with the discharge energy.

In wire electrical discharge machining (EDM), bubbles generate by evaporation of working fluid due to high temperature of arc plasma. Moreover, they are generally excluded from machined kerf by nozzle jet flushing, and influence debris exclusion and machining characteristics. Furthermore, the bubble conditions would be changed by machining conditions, but they have not yet been clarified sufficiently. In this study, the influences of nozzle jet flushing on the state of bubbles were discussed by using high-speed observation of them in the machined kerf and the image analysis.

In our previous works, we have proposed a method of electrochemical machining (ECM) using bipolar pulses and auxiliary electrode, namely bipolar pulsed ECM. Experimental results confirmed that the method can generate intensive bubbles to reduce stray corrosion. In addition, the follow-up experiments showed that the diameter of machined holes is smaller than the tool diameter under some experimental parameters, which is an unclear point about the mechanism of bipolar pulsed ECM. Therefore, in this paper, we tried to get a relevant law and interpretation by experimental results and analysis in bipolar pulsed ECM.

In electrochemical machining (ECM) of deep narrow grooves, it can be effectively solved the problem of difficult by-product discharge through applying ultrasonic vibration to the tool electrode. However, the vibration application will affect the distribution of bubble in the processing area, which may cause the machining groove width become uneven. To solve this problem, a method of dual-frequency transverse ultrasonic-assisted electrochemical machining to change the vibration frequency intermittently was proposed. In this paper, the influence of the vibrating tool electrode on ECM characteristics under dual ultrasonic frequency is analyzed by COMSOL Multiphysics. The results show that the distribution of bubble and flow velocity in the machining area is similar to ultrasonic vibration transformation under dual-frequency ultrasonic vibration, which can improve the efficiency of processing and solves the problem of uneven section under single ultrasonic frequency.

Accuracy of electrochemical machining (ECM) is reduced due to stray corrosion caused by the current in the non-machining area. A processing method to limit the distribution of electrolyte using the absorption of porous solid ball has been proposed. With this method, a contact force between the ball and the workpiece occurs since the porous ball contacts and rolls over the workpiece surface. A strong force due a small distance may break the ball and scratch the workpiece surface. In this paper, to solve the above-mentioned problem, the method of ECM using porous solid ball is improved to keep the ball not contact with the workpiece. The different characteristics between contact and non-contact methods are experimentally investigated. The experimental results show that the non-contact processing method can effectively improve the machining shape, and obtain better machining quality.

To understand how intelligence is generated based on neural connections using neural network models, in addition to train Spiking Neural Networks (SNNs) for accomplishing a given cognitive task, another important topic is to investigate how SNNs generate meaningful activities in response to external stimuli. Previous studies have proposed that a low rank connectivity matrix in Recurrent Neural Networks (RNNs) can provide the key mechanism of computation ability of connected neurons. However, these studies are unconvincing when applied to real neurons because the neuron models used in these studies were overly simplistic and lacked adequate biological plausibility such as the definition of reversal potential and excitatory-inhibitory interaction. Addressing this lack, our research develops more biologically plausible SNNs to reveal the origin of computation ability in neuron populations. Here we use Voltage Dependent Theta Neuron Model to construct SNNs with low rank connectivity. In addition to connectivity parameters, we also investigate the effect of those biological parameters like different synaptic decay times and inhibitory connections on the performance of SNNs. Consequently, the findings from this research have greater applicability to real neural connections.

In the electrocardiogram (ECG) detection using copper wire woven electrodes without direct contact with human skin, the motion artifact signal caused by the unfixed electrode in daily activities is more obvious. Compared with the previous approach which only estimated and removed motion artifacts in small body movements by using a color sensor, in this study, the accelerometers, gyroscopes and color sensor are used, which shows the estimation ability for larger body movements during daily activities. The 3 sensors and ECG measurement device which used the copper wire woven electrodes are fused with the adaptive filtering algorithm to estimate and remove the motion artifacts. The average SNR was improved by 2dB under the continuous motion of the measured object.

In this research, a wireless and passive relative displacement sensor structure is designed based on a backscatter communication system, providing a flexible and cost-efficient option for Structure Health Monitoring (SHM) application. The proposed sensor arranges a pair of Copper-Clad Laminates (CCL) in parallel with adjustable distance as a RF resonator. To wirelessly detect the frequency characteristic of proposed RF resonator, a backscatter communication system is employed, and the system transmission loss (S21) is measured. According to the results from both simulation and experiments, a consistent relationship is established between S21 peak frequency shifting and the distance between paralleled laminates. In relative displacement experiments, a resolution of under 0.01 mm within a 0.6 mm sensing range is achieved. Compared to the previous research, the proposed sensor structure enables vertical relative displacement sensing between paralleled laminates, which increases the flexibility in sensor deployment within confined structures.

We have developed a micro-fabrication method of diamond substrate with Ni molds. Diamond substrate was etched by compression of Ni molds at high temperatures.

This study aims to augment the antifouling properties of glass electrodes utilized in wireless rumen pH sensors by introducing a new type of flat glass electrode with modified surface topography. This modification comprises three distinct topographical configurations: Line and Space, Holes, and Pillars, each with dimensions ranging from 1 µm to 3 µm, a pitch between 2 µm to 6 µm, and a uniform depth of 1 µm. Employing sophisticated fabrication methods, these patterns were created using a synergistic application of photolithography, electron beam lithography, along with both wet and dry etching processes. Post-fabrication, the antifouling performance of these topographical interventions was rigorously evaluated through in vitro assay experiments.

As technology advances, temperature sensing is becoming a key issue in the cryogenic community. Key examples include the monitoring of aerospace equipment such as a spacecraft and the monitoring of automated production lines such as a cryogenic gas recovery plant. In such cryogenic environments, traditional temperature sensors are either inconvenient or complicated due to weak low-temperature tolerances and inaccessible working positions.To solve these problems, we propose a novel wireless passive temperature sensing method for cryogenic applications by only using low-temperature tolerant passive devices. By innovatively integrating a thermistor on a backscattering antenna, the temperature inside a cryogenic environment is transferred to a wirelessly obtainable return loss. In the measurement, the thermistor’s resistance changes with the temperature, which leads to an impedance mismatch between the antenna and the load. As a result, the sensor’s return loss is modulated by the temperature. The return loss is then wirelessly obtained by using a backscattering method, thus the temperature is derived.The purpose of this research is to propose a new sensing methodology, to monitor the temperature in a cryogenic environment wirelessly and passively.

The study focuses on enhancing microneedle technology for efficient drug and vaccine delivery through the skin's outer layer. Traditional microneedle manufacturing faces challenges such as complex processes and potential denaturation of active ingredients. The new approach introduces "powder-attached microneedles," involving a silicone adhesive layer for attaching formulated drug or vaccine powders. This method overcomes solubility issues and minimizes the risk of ingredient separation during manufacturing. The research uses ovalbumin and teriparatide as model substances. Results demonstrate successful delivery of dried powder, inducing immune responses comparable to intramuscular administration. Powder-attached microneedles offer advantages like convenience, storage stability, and cost reduction. For teriparatide, powder-attached microneedles show pharmacokinetic properties similar to intradermal administration of liquid formulations, providing rapid dissolution and efficient drug delivery. This innovative approach holds promise for thermally sensitive vaccines and structurally weak formulations.

Nanoimprint lithography is one of the pattern transfer method using mold. Outline of fabrication methods for nano-mold and its limitation are discussed.

In order to employ generative AI to save time in planning experiments, it becomes important to design the prompts. There are three critical elements for designing the prompt: role, purpose, and requirements. In the role, it is important to give the 1st person + prerequisites, as in 'I will do ... and the prerequisites include ...'. In the purpose, it is critical to describe the actual actions to be performed in detail. Then, several requirements are set up. For each requirement, enter the same prompts into CHAT-GPT, except for the requirement and obtain the answer. By appropriately integrating the group of answers received, the required set of keywords can be obtained. Such a series of tasks dramatically reduces the time required for literature searches and literature readings in designing an experimental strategy.