磁気トンネル接合素子の微細加工プロセスダメージ現象の解析と酸化後処理によるその回復技術に関する研究

要約のみTohoku University遠藤哲郎課

Design and Implementation of a Wireless Charging-Based Cardiac Monitoring System Focused on Temperature Reduction and Robust Power Transfer Efficiency

Wireless power transfer systems are increasingly used as a means of charging implantable medical devices. However, the heat or thermal radiation from the wireless power transfer system can be harmful to biological tissue. In this research, we designed and implemented a wireless power transfer system-based implantable medical device with low thermal radiation, achieving 44.5% coil-to-coil efficiency. To suppress thermal radiation from the transmitting coil during charging, we minimized the ESR value of the transmitting coil. To increase power transfer efficiency, a ferrite film was applied on the receiving part. Based on analyses, we fabricated a cardiac monitoring system with dimensions of 17 x 24 x 8 mm(3) and implanted it in a rat. We confirmed that the temperature of the wireless charging device increased by only 2 degrees C during the 70 min charging, which makes it safe enough to use as an implantable medical device charging system.11Ysciescopu

Cooperative control for a flight array of UAVs and an application in radar jamming

This paper proposes a flight array system and an integrated approach to cope with its operational issues raised in mission-planning level (i.e., task allocation) and control level (i.e., control allocation). The proposed flight array system consists of multiple ducted-fan UAVs that can assemble with each other to fly together, as well as dissemble themselves to fly individually for accomplishing a given mission. To address the task allocation problem, a game-theoretical framework is developed. This framework enables agents to converge into an agreed task allocation in a decentralised and scalable manner, while guaranteeing a certain level of global optimality. In addition, this paper suggests a cooperative control scheme based on sliding mode control and weighted pseudo-inverse techniques so that the system’s non-linearity and control allocation issue are effectively handled. As a proof-of-concept, a prototype simulation program is developed and validated in a cooperative jamming mission. The numerical simulations manifest the feasibility of effectiveness of the proposed approach

An integrated decision-making framework of a heterogeneous aerial robotic swarm for cooperative tasks with minimum requirements

Given a cooperative mission consisting of multiple tasks spatially distributed, an aerial robotic swarm’s decision-making issues include team formation, team-to-task assignment, agent-to-work-position assignment and trajectory optimisation with collision avoidance. The problem becomes even more complicated when involving heterogeneous agents, tasks’ minimum requirements and fair allocation. This paper formulates all the combined issues as an optimisation problem and then proposes an integrated framework that addresses the problem in a decentralised fashion. We approximate and decouple the complex original problem into three subproblems (i.e. coalition formation, position allocation and path planning), which are sequentially addressed by three different proposed modules. The coalition formation module based on game theories deals with a max-min problem, the objective of which is to partition the agents into disjoint task-specific teams in a way that balances the agents’ work resources in proportion to the task’s minimum workload requirements. For agents assigned to the same task, given reasonable assumptions, the position allocation subproblem can be efficiently addressed in terms of computational complexity. For the trajectory optimisation, we utilise a Model Predictive Control and Sequential Convex Programming algorithm, which reduces the size of the problem so that the agents can generate collision-free trajectories on a real-time basis. As a proof of concept, we implement the framework into an unmanned aerial vehicle swarm’s cooperative stand-in jamming mission scenario and show its feasibility, fault tolerance and near-optimality based on numerical experiment

Binary particle swarm optimized 2 × 2 power splitters in a standard foundry silicon photonic platform

Compact power splitters designed ab initio using binary particle swarm optimization in a 2D mesh for a standard foundry silicon photonic platform are studied. Designs with a 4.8  μm×4.8  μm footprint composed of 200  nm×200  nm and 100  nm×100  nm cells are demonstrated. Despite not respecting design rules, the design with the smaller cells had lower insertion losses and broader bandwidth and showed consistent behavior across the wafer. Deviations between design and experiments point to the need for further investigations of the minimum feature dimensions

Preclinical Analysis of Irreversible Electroporation on Rat Liver Tissues Using a Microfabricated Electroporator

A microfabricated electroporator (MFE) for the irreversible electroporation (IRE) of tissues has been developed by miniaturizing a clinical electroporator with a two-needle array while keeping the same electric field strength distribution. Since IRE was brought to special attention as one of the local tissue ablation techniques to treat tumors, many preclinical studies have been conducted to investigate the efficacy of IRE on animal tissues. However, some technical difficulties have been frequently encountered due to the macroscale dimension of clinical electroporators, particularly in experiments on small animal models such as the mouse or rat. Here, the MFE was proposed to solve the associated problems, resulting in time-and cost-effective experimental procedures. With the developed MFE, the effect of IRE on rat liver tissues was analyzed with time by immunohistological stainings and electrical measurement, and the experimental results were compared with those operated with the corresponding real-scale clinical electroporator.Choi YS, 2009, ANAL CHEM, V81, P3517, DOI 10.1021/ac900055rMaor E, 2009, PLOS ONE, V4, DOI 10.1371/journal.pone.0004757Pavlin M, 2008, BIOELECTROCHEMISTRY, V74, P38, DOI 10.1016/j.bioelechem.2008.04.016Sersa G, 2008, EJSO-EUR J SURG ONC, V34, P232, DOI 10.1016/j.ejso.2007.05.016Rubinsky B, 2007, TECHNOL CANCER RES T, V6, P255Onik G, 2007, TECHNOL CANCER RES T, V6, P295Al-Sakere B, 2007, TECHNOL CANCER RES T, V6, P301Maor E, 2007, TECHNOL CANCER RES T, V6, P307Garon EB, 2007, INT J CANCER, V121, P675, DOI 10.1002/ijc.22723Esser AT, 2007, TECHNOL CANCER RES T, V6, P261Lee EW, 2007, TECHNOL CANCER RES T, V6, P287Kimelman N, 2007, TISSUE ENG, V13, P1135, DOI 10.1089/ten.2007.0096Lavee J, 2007, HEART SURG FORUM, V10, pE162, DOI 10.1532/HSF98.20061202Rubinsky B, 2007, TECHNOL CANCER RES T, V6, P37Liu L, 2006, CANCER RES, V66, P11851, DOI 10.1158/0008-5472.CAN-06-1377Marty M, 2006, EJC SUPPL, V4, P3, DOI 10.1016/j.ejcsup.2006.08.002Sersa G, 2006, EJC SUPPL, V4, P52, DOI 10.1016/j.ejcsup.2006.08.007Edd JF, 2006, IEEE T BIO-MED ENG, V53, P1409, DOI [10.1109/TBME.2006.873745, 10.1109/TMBE.2006.873745]Miller L, 2005, TECHNOL CANCER RES T, V4, P699Sel D, 2005, IEEE T BIO-MED ENG, V52, P816, DOI 10.1109/TBME.2005.845212Davalos RV, 2005, ANN BIOMED ENG, V33, P223, DOI 10.1007/s10439-005-8981-8Pliquett U, 2004, BIOELECTROCHEMISTRY, V62, P83, DOI 10.1016/j.biolechem.2003.11.001Davalos RV, 2003, BIOELECTROCHEMISTRY, V61, P99, DOI 10.1016/j.bioelechem.2003.07.001Weaver JC, 2003, IEEE T DIELECT EL IN, V10, P754, DOI 10.1109/TDEI.2003.1237325Gothelf A, 2003, CANCER TREAT REV, V29, P371, DOI 10.1016/S0305-7372(03)00073-2Gehl J, 2003, ACTA PHYSIOL SCAND, V177, P437Leu JI, 2003, J CLIN INVEST, V111, P129, DOI 10.1172/JCI200316712Deng ZS, 2001, PHYSICA A, V300, P521Ryttsen F, 2000, BIOPHYS J, V79, P1993Dev SB, 2000, IEEE T PLASMA SCI, V28, P206, DOI 10.1109/27.842905Duffy DC, 1998, ANAL CHEM, V70, P4974Boone K, 1997, J MED ENG TECHNOL, V21, P201Weaver JC, 1996, BIOELECTROCH BIOENER, V41, P135*I LAB AN RES NAT, 1996, GUID CAR US LAB ANABIDOR IG, 1993, BIOCHIM BIOPHYS ACTA, V1152, P207DILLER KR, 1992, MODELING BIOHEAT TRAMIR LM, 1991, CR ACAD SCI III-VIE, V313, P613DUCK FA, 1990, PHYS PROPERTIES ISSUKINOSITA K, 1979, BIOCHIM BIOPHYS ACTA, V554, P479PENNES HH, 1948, J APPL PHYSIOL, V1, P93

Implantable photonic neural probes for light-sheet fluorescence brain imaging

Significance: Light-sheet fluorescence microscopy (LSFM) is a powerful technique for highspeed volumetric functional imaging. However, in typical light-sheet microscopes, the illumination and collection optics impose significant constraints upon the imaging of non-transparent brain tissues. We demonstrate that these constraints can be surmounted using a new class of implantable photonic neural probes. Aim: Mass manufacturable, silicon-based light-sheet photonic neural probes can generate planar patterned illumination at arbitrary depths in brain tissues without any additional micro-optic components. Approach: We develop implantable photonic neural probes that generate light sheets in tissue. The probes were fabricated in a photonics foundry on 200-mm-diameter silicon wafers. The light sheets were characterized in fluorescein and in free space. The probe-enabled imaging approach was tested in fixed, in vitro, and in vivo mouse brain tissues. Imaging tests were also performed using fluorescent beads suspended in agarose. Results: The probes had 5 to 10 addressable sheets and average sheet thicknesses <16 μm for propagation distances up to 300 μm in free space. Imaging areas were as large as ≈240 μm × 490 μm in brain tissue. Image contrast was enhanced relative to epifluorescence microscopy. Conclusions: The neural probes can lead to new variants of LSFM for deep brain imaging and experiments in freely moving animals

Implantable photonic neural probes for light-sheet fluorescence brain imaging

Significance: Light-sheet fluorescence microscopy is a powerful technique for high-speed volumetric functional imaging. However, in typical light-sheet microscopes, the illumination and collection optics impose significant constraints upon the imaging of non-transparent brain tissues. Here, we demonstrate that these constraints can be surmounted using a new class of implantable photonic neural probes. Aim: Mass manufacturable, silicon-based light-sheet photonic neural probes can generate planar patterned illumination at arbitrary depths in brain tissues without any additional micro-optic components. Approach: We develop implantable photonic neural probes that generate light sheets in tissue. The probes were fabricated in a photonics foundry on 200 mm diameter silicon wafers. The light sheets were characterized in fluorescein and in free space. The probe-enabled imaging approach was tested in fixed and in vitro mouse brain tissues. Imaging tests were also performed using fluorescent beads suspended in agarose. Results: The probes had 5 to 10 addressable sheets and average sheet thicknesses < 16 μm for propagation distances up to 300 μm in free space. Imaging areas were as large as ≈ 240 μm x 490 μm in brain tissue. Image contrast was enhanced relative to epifluorescence microscopy. Conclusions: The neural probes can lead to new variants of light-sheet fluorescence microscopy for deep brain imaging and experiments in freely-moving animals

Multifunctional Smart Ball Sensor for Wireless Structural Health Monitoring in a Fire Situation

A variety of sensor systems have been developed to monitor the structural health status of buildings and infrastructures. However, most sensor systems for structural health monitoring (SHM) are difficult to use in extreme conditions, such as a fire situation, because of their vulnerability to high temperature and physical shocks, as well as time-consuming installation process. Here, we present a smart ball sensor (SBS) that can be immediately installed on surfaces of structures, stably measure vital SHM data in real time and wirelessly transmit the data in a high-temperature fire situation. The smart ball sensor mainly consists of sensor and data transmission module, heat insulator and adhesive module. With the integrated device configuration, the SBS can be strongly attached to the target surface with maximum adhesion force of 233.7-N and stably detect acceleration and temperature of the structure without damaging the key modules of the systems even at high temperatures of up to 500 degrees C while ensuring wireless transmission of the data. Field tests for a model pre-engineered building (PEB) structure demonstrate the validity of the smart ball sensor as an instantly deployable, high-temperature SHM system. This SBS can be used for SHM of a wider variety of structures and buildings beyond PEB structures