본 연구는 딥러닝 영상 재구성 기법을 적용한 8개의 뇌질환군의 감마나이프 수술 계획용 자기공명영상(magnetic resonance imaging, MRI)의 유용성을 알아보고자 하였다. 연구 방법은 전이성 뇌종양, 뇌동정맥 기형, 수막종, 뇌하수체선종, 삼차신경통, 청신경초종, 맥락얼기 유두종, 해면상 혈관종, 총 8개의 질병을 진단받은 사람들의 T2 강조 영상(T2 weighted imaging, T2WI), 조영증강 T1 강조영상(contrast enhancement T1 weighted imaging, CE-T1WI)의 방법으로 검사한 MRI 영상을 SwiftMR을 이용하여 딥러닝 영상 재구성 기법인 디노이징(denoising)과 초해상도(super resolution)가 적용된 영상을 획득하였다. 이에 대한 성능 평가는 최대 신호대잡음비(peak signal to noise ratio, PSNR), 구조적 유사도(structural similarity index measure, SSIM), 감마나이프 방사선수술(gamma knife radiosurgery, GKRS)의 좌표계로 평가하였다. 그 결과, 원본영상을 기반으로 영상 품질이 개선된 영상의 PSNR과 SSIM은 높은 수치를 나타냄으로써 MRI 영상의 재구성이 문제없이 이루어졌고, GKRS의 수술 좌표계 또한 변화를 보이지 않았다. 결론적으로 딥러닝 영상 재구성 기법은 영상 품질 향상과 영상 보존에서 뛰어난 성능을 보임과 동시에 좌표계도 변화를 보이지 않아서, 딥러닝 영상 재구성 기법은 감마나이프 수술 계획에 유용하게 사용할 수 있는 기법임을 확인하였다.

에듀테크 시대에 접어들면서 디지털 기술을 활용한 학습 방식이 점점 확대되고 있으며, 특히 모바일 기반 애플리케이션 을 활용한 학습이 적극적으로 도입되고 있다. 이러한 학습 방식은 학습자의 참여도를 높이고, 흥미를 유발하며, 학습 효율성 향상에 긍정적인 영향을 미치고 것으로 보고되고 있다. 본 연구는 자기공명영상학 학습에서 모바일 기반 애플리 케이션 사용에 대한 학습자들의 인식, 학습 효과, 학습 만족도를 알아보고자 하였다. 대구시 소재 S 대학교 자기공명영 상학을 수강한 2, 3학년 학생 70명을 대상으로 2024년 11월 24일부터 29일까지 수업 후 모바일 애플리케이션을 활용한 퀴즈 활동을 시행하였다. 연구 결과, 애플리케이션 활용에 대한 학습자들의 인식 평균 점수는 4.58±0.66, 학습 효과는 4.61±0.62, 학습 만족도는 4.58±0.65로 나타났다. 또한, 애플리케이션 활용 전후 비교 분석에서 인식 (활용 전 3.62±0.97, 활용 후 4.58±0.66), 학습 효과(활용 전 3.60±0.92, 활용 후 4.61±0.62), 학습 만족도(활용 전 3.64±0.93, 활용 후 4.58±0.65) 모두 통계적으로 유의한 차이가 있었다(p<0.05). 이러한 결과는 자기공명영상학 교육에서 모바일 애플리케이션 기반 학습이 학습자의 참여도, 이해도, 만족도를 높이는 데 효과적임을 시사한다. 따라서 자기공명영상학뿐만 아니라 다양한 전공 분야에서도 애플리케이션 기반 학습이 유용한 교육 도구로 활용될 수 있으며, 향후 교육 및 임상 실습 현장에서 적용 가능한 기초자료로 활용될 수 있을 것 기대된다.

Magnons have unique properties, including long propagation length, and can exist in insulators. Magnon valve structures, which consist of two magnetic insulating layers, offer a promising approach for advanced magnetoresistive randomaccess memory (MRAM) technology and an alternative to the limitations of traditional electronic devices. In this study, we investigate a magnon valve structure that incorporates a platinum (Pt) spacer between two magnetic insulator layers, specifically yttrium iron garnet (Y3Fe5O12, YIG). Structural characterization of the YIG/Pt/YIG magnon valve was carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM), confirming the high-quality growth of the multilayer structure. The magnon valve behavior was assessed through vibrating sample magnetometry (VSM) and spin Seebeck effect (SSE) measurements. Our results demonstrate magnon valve behavior, which becomes apparent as the Pt spacer reaches a thickness sufficient to decouple the magnetization of the YIG layers. The magnon valve ratio of the magnon valve can be modulated, and clarity of the those states can be enhanced.

Efforts have been extensively undertaken to tackle overheating problems in advanced electronic devices characterized by high performance and integration levels. Thermal interface materials (TIMs) play a crucial role in connecting heat sources to heat sinks, facilitating efficient heat dissipation and thermal management. On the other hand, increasing the content of TIMs for high thermal conductivity often poses challenges such as poor dispersion and undesired heat flow pathways. This study aims to enhance the through-plane heat dissipation via the magnetic alignment of a hybrid filler system consisting of exfoliated graphite (EG) and boron nitride (BN). The EG acts as a distributed scaffold in the polymer matrix, while the BN component of the hybrid offers high thermal conductivity. Moreover, the magnetic alignment technique promotes unidirectional heat transfer pathways. The hybrid exhibited an impressive thermal conductivity of 1.44 W m− 1 K− 1 at filler contents of 30 wt. %, offering improved thermal management for advanced electronic devices.

In order to overcome the limitations of linear vibration energy harvesters and those using mechanical plucking, magnetic plucking vibration energy harvesters (MVEs) have garnered significant interest. This paper presents parametric studies aimed at proposing design guidelines for MVEs and compares two magnetic force models that describe interactions between two permanent magnets. A mathematical model describing the energy harvester is employed, followed by the introduction of two magnetic force models: an analytic model and an inverse square model. Subsequently, numerical simulations are conducted to investigate dynamic characteristics of MVEs, analyzing results in terms of tip displacement, voltage output, and harvested energy. Parametric studies vary the distance between magnets, the speed of the external magnet, and the beam shape. Results indicate that reducing the distance between magnets enhances energy harvesting effectiveness. An optimal velocity for the external magnet is observed, and studies on beam shape suggest greater energy harvesting when the shape favors deflection.

This research investigates into using a highly efficient magnetic abrasive finishing (MAF) method to refine the surface of an Inconel 625 bar intended for use as a stem in a hydrogen solenoid valve. In contrast to the previous choice of STS 316 material, Inconel 625 was selected due to its superior properties. The cylindrical surface of Inconel 625 bars underwent polishing using the super-fast MAF process, employing varying rotational speeds ranging from 1000 to 25,000 RPM and a potent magnetic field of 550 mT. The study evaluated the polishing outcomes concerning abrasive type, rotational speeds, and processing duration. The results demonstrated the achievement of an exceptionally smooth surface on the Inconel 625 bar, with the surface roughness (Ra) reduced significantly, reaching 0.03 μm under optimal conditions. These conditions included employing carbon nanotube (CNT) particles of 0.04g, PCD diamond abrasive of 1g, Fe of 9g, 0.5g of light oil, and a processing time of 16 minutes at 15,000 RPM. Furthermore, Ansys analysis confirmed the mechanical integrity of the polished Inconel 625 bar, exhibiting suitable strain, equivalent stress, and safety factors. This substantiates the feasibility of employing Inconel 625 bars in hydrogen tanks, surpassing the conventional STS 316L bars.

The intensive development of the petrochemical industry globally reflects the necessity of an efficient approach for oily sludge and wastewater. Hence, for the first time, the current study utilized magnetic waxy diesel sludge (MWOPS) to synthesize activated carbon coated with TiO2 particles for the removal of total petroleum hydrocarbons (TPH) and COD from oily petroleum wastewater (OPW). The photocatalyst was characterized using CHNOS, elemental analysis was performed using X-ray fluorescence spectroscopy (XRF), field emission scanning electron microscope (FESEM), high-resolution transmission electron microscope (HR-TEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectrometer (FTIR), Raman, energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), MAP thermo-gravimetric analysis/ differential thermo-gravimetric (TGA–DTG), Brunauer–Emmett–Teller (BET), diffuse reflectance spectroscopy (DRS), and vibrating sample magnetometer (VSM). The optimization of synthesized highly porous AC/Fe3O4/TiO2 photocatalyst was conducted considering the impacts of pH, temperature, photocatalyst dosage, and UVA6W exposure time. The results demonstrated the high capacity of the MWOPS with inherent magnetic potential and desired carbon content for the removal of 91% and 93% of TPH and COD, respectively. The optimum conditions for the OPW treatment were obtained at pH 6.5, photocatalyst dosage of 250 mg, temperature of 35 °C, and UVA6W exposure time of 67.5 min. Moreover, the isotherm/kinetic modeling illustrated simultaneous physisorption and chemisorption on heterogeneous and multilayer surfaces. Notably, the adsorption efficiency of the AC/Fe3O4/TiO2 decreased by 4% after five adsorption/desorption cycles. Accordingly, the application of a well-designed pioneering photocatalyst from the MWOPS provides a cost-effective approach for industry manufacturers for oily wastewater treatment.

We investigated dynamic interaction between adjacent magnetic loops in the solar atmosphere, which is a process of volume shrinkage with nonuniform acceleration caused by Lorentz force. When these loops locally have different thermal and dynamic properties, a significant discrepancy between their translational motions driven by means of that force may arise, leading to the dynamic interaction. We use both numerical simulation and analytic model of magnetic piston-driven wave to evaluate how much a single event of the interaction contributes to increasing the temperature in the upper chromosphere. The model shows a possibility that a chromospheric plasma is heated by the single event to have transition region temperature, which is typically several tens of times higher than chromospheric temperature. The model also provides an insight into the formation height of the transition region.

The structure and magnetic properties of composite powders prepared by ball milling a mixture of Fe2O3 ‧ (0.4-1.0)Fe were investigated. Hysteresis loops and differential scanning calorimetry (DSC) curves are used to characterize the materials and to examine the effect of the solid state reaction induced by ball milling. The results showed that a solid state reaction in Fe2O3 ‧ (0.4-1.0)Fe clearly proceeds after only 1 h of ball milling. The system is characterized by a positive reaction heat of +2.23 kcal/mole. The diffraction lines related to Fe2O3 and Fe disappeared after 1 h of ball milling and, instead, diffraction lines of the intermediate phase of Fe3O4 plus FeO formed. The magnetization and coercivity of the Fe2O3 ‧ 0.8Fe powders were changed by the solid state reaction process of Fe2O3 by Fe during ball milling. The coercivity of the Fe2O3 ‧ 0.8Fe powders increased with increasing milling time and reached a maximum value of 340 Oe after 5 h of ball milling. This indicates the grain size of Fe3O4 was clearly reduced during ball milling. The magnetic properties of the annealed powders depend on the amount of magnetic Fe and Fe3O4 phases.

This work focuses on the fabrication of excellent magnetic structures for trapping breast cancer cells. Micromagnetic structures were patterned for trapping cancer cells by depositing 30 nm of permalloy on a silicon substrate. These structures were designed and fabricated using two fabrication techniques: electron beam lithography and laser direct writing. Two types of magnetic structures, rectangular wire and zig-zagged wire, were created on a silicon substrate. The length of each rectangular wire and each straight line of zig-zagged wire was 150 μm with a range of widths from 1 to 15 μm for rectangular and 1, 5, 10 and 15 μm for zigzag, respectively. The magnetic structures showed good responses to the applied magnetic field despite adding layers of silicon nitride and polyethylene glycol. The results showed that Si + Si3N4 + PEG exhibited the best adhesion of cells to the surface, followed by Si + Py + Si3N4 + PEG. concentration of 5-6 with permalloy indicates that this layer affected silicon nitride in the presence of Polyethylene glycolPEG.

본 연구에서는 3D 프린팅 기술과 인체공학 순설계를 이용하여 턱관절 자기공명영상 동적 턱관절 검사 보조기구를 개발하고자 하였다. 3D 프린팅 기술 재료는 3D 프린터(Sindo, 3DWOX1, Korea), 3D 모델러 프로그램(Fusion 360, autodesk, USA), PLA(polylactic Acid) 필라멘트 소재를 이용하였고, 영상 검사는 3.0T 자기공명영상 장비 (Magnetom Vida, Siemens, Germany)를 사용하였다. 개발 방법은 성인 30명(남:13명, 여:17명, 평균나이 22.9±2.0세)의 안면뼈 CT(computed tomography) 검사의 단면 영상을 역학적으로 실측하여 상/하악궁의 형상을 모델링하였다. 모델링된 파일은 FDM(fused deposition modeling) 방식으로 3D 프린팅하였다. 출력된 보조기구는 자화 감수성 인공물 실험, 동적 영상 비교, 만족도 평가로 성능을 평가하였다. 그 결과, 자화감수성 인공물 발생은 개발된 개구 보조 장비와 비교하여 모든 영상에서 유의한 차이가 없었다. 동적 비교 영상에서는 TSE 기법이 모든 평가 법에서 가장 우수한 영상 품질을 보였다. 만족도 평가에서는 피검자는 평균 4.3점, 방사선사는 평균 4.4점으로 높은 만족도를 보였다. 결론적으로 인공물 발생이 없는 환자 맞춤형 보조기구에 개구의 동적 기능이 탑재된 보조기구 를 개발하였다.

본 연구에서는 자기공명영상검사실 방사선사의 환자안전 문화 인식을 분석하고자 하였다. 수도권 자기공명영상검사 실에서 근무하는 방사선사 109명을 대상으로 일반적인 특성, 실태조사, 환자안전 문화 인식에 대해 설문 조사하였 다. 의료종사자들을 대상으로 개발된 한국형 환자안전문화 측정 도구에서 최상위 리더십을 경영진으로, 부서장이라 는 단어를 파트장으로 수정하였고 전문가 5인에게 내용 타당도를 검증받았다. 결과적으로 자기공명영상검사실에서 근무하는 방사선사의 환자안전 문화 인식 점수는 평균 3.97로 높았지만, 안전사고경험 비율이 65.1%로 높게 나타났 다. 따라서 정기적으로 이루어지고 있는 자기공명영상검사 안전교육의 효율성 제고를 위한 연구가 필요하며 본 연구 가 기초자료를 제공할 것이라 사료된다.

A force-free field (FFF) is determined solely by the normal components of magnetic field and current density on the entire boundary of the domain. Methods employing three components of magnetic field suffer from overspecification of boundary conditions and/or a nonzero divergence-B problem. A vector potential formulation eliminates the latter issue, but introduces difficulties in imposing the normal component of current density at the boundary. This paper proposes four different boundary treatment methods within the vector potential formulation. We conduct a comparative analysis of the vector potential FFF solvers that we have developed incorporating these methods against other FFF codes in different magnetic field representations. Although the vector potential solvers with the new boundary treatments do not outperform our poloidal-toroidal formulation code, they demonstrate comparable or superior performance compared to the optimization code in SolarSoftWare. The methods developed here are expected to be readily applied not only to force-free field computations but also to time-dependent data-driven simulations.

In this study, a low-cost and easily recyclable porous green adsorbent (magnetic porous loofah biochar, MPLB) was synthesized by modifying the almost zero-cost loofah biochar material with Fe3O4. The successful synthesis of the material was demonstrated by XRD, FTIR, SEM, VSM, and BET. In addition, the material exhibits outstanding magnetic separation performance (40.01 umg/g) allowing for rapid recovery within just 90 s. The adsorption process of phenol on MPLB was found to be spontaneous and endothermic. The experimental data fit exceptionally well with the pseudo-second-order kinetic model and Langmuir model (R2 > 0.99), indicating that the dominant adsorption mechanisms involved monolayer adsorption and chemisorption. These interactions were attributed to host–guest interaction, π–π conjugation, hydrogen bonding, and pore filling. The maximum adsorption capacity calculated using the Langmuir model at 298 K is 39.4 mg/g. Importantly, even after undergoing seven cycles of recycling, MPLB retained 78% of its initial adsorption capacity. In simulated experiments employing MPLB for phenol removal in actual wastewater, an impressive removal rate of 96.4% was achieved. In conclusion, MPLB exhibits significant potential as an effective adsorbent for phenol removal in wastewater.