Beam quality is changed about magnetic field of bending magnet. Evaluation of beam quality using PDD(Percentage Depth Dose) at 10cm depth at recommendation of AAPM(America Academy of Pain Medicine). However this evaluation shows fragmentary element. Therefore this study is applied to three value, 10cm divided by 5cm depth PDD, 20cm divided by 10cm depth PDD, 30cm divided by 20cm depth PDD, at change the magnetic field. PDD is measured at magnetic field changed ±1%, ±2% at 6MV(Mega Voltage), 10MV photon. The plan technique is 3 portal plan using Core-Plan at human pelvic phantom. Conventional and presented methods are compared at maximum and minimum dose. The presented method increased discernment of relieve the unequal distribution and energy area than conventional method. Henceforth, application of presented method will be considered. Development of energy measurement method and detector miniaturization will be needed about continuous study.

This study investigated the magnetic properties and frequency dispersion of complex permeability of Ni-Zn-Co ferrites used for magnetic shielding in near field communication (NFC) system. The sintered specimens of (Ni0.7Zn0.3)1-xCoxFe2O4 composition were prepared by the conventional ceramic processing. The coercive force and saturation magnetization were measured by vibrating sample magnetometer. The complex permeability was measured by RF impedance analyzer in the range of 1 MHz~1.8 GHz. The coercive force increased and saturation magnetization decreased with increasing the Co substitution. The real and imaginary parts of complex permeability decreased and the resonance frequency increased with Co substitution, which was attributed to the increase in crystal anisotropy field and reduction in saturation magnetization. The effect of Co substitution could be found in reducing the magnetic loss to nearly zero at the operating frequency of NFC (13.56 MHz).

한국지질자원연구원은 몽골 광물자원청과 공동으로 우기누르 철-망간 광화대에 대한 공동 연구를 수행하였다. 이의 일환으로 수행된 육상 자력탐사에서 획득한 자료를 바탕으로 3차원 자력 역산을 수행하였으며, 3차원 지질모델링 기술을 이용하여 철-망간 광화대에 대한 3차원 영상화 및 광체 평가를 위한 연구를 수행하였다. 총자력 이상의 분포 특성을 통해 연구지역의 광상에서 지표 노두로부터 수평적으로 연장되는 광체의 부존 가능성을 확인하였다. 또한, Fe 함량과 상관성이 높은 자기감수율 역산 결과를 토대로 연구지역의 제 1광상 및 제 2광상 모두에서 지표에서 드러난 광체가 지하 하부로 연장되어 있는 것으로 해석되어, 지표에 드러나지 않은 광체의 부존 가능성이 높은 것으로 판단된다. 시추 조사를 통해 일부 대표 지역의 광체 품위 자료가 확보되고 이번 연구결과와의 복합 해석을 수행한다면 효과적인 개발 가능성 평가가 가능할 것으로 판단된다.

Ischemic stroke is the most common type of stroke in humans. The purpose of this study was to evaluate the diagnostic value of magnetic resonance imaging (MRI) in a canine model of stroke. Ischemic stroke was induced by using prepared autologous thrombus. The dogs were placed in lateral recumbency on the operation table and the cervical area of each dog was sterilized by using alcohol. After making a cervical incision, the common carotid artery and internal carotid artery (a branch of the common carotid artery that supplies an anterior part of the brain) were exposed. A 200 μL injection of the autologous thrombus prepared 24 hr prior to surgery was delivered with a 20 gauge venous catheter through an internal carotid artery. After successful delivery of the autologous thrombus, the venous catheter was removed, and the cervical incision was sutured. Neurologic signs including generalized seizures, tetraparesis, and altered mental status, were observed in all 3 dogs after induction of ischemic stroke and the signs manifested immediately after awakening from anesthesia. T1- and T2-weighted images and fluid-attenuated inversion recovery (FLAIR) images of the brain were acquired 1 day before and 1 day after surgery. On the day following ischemic stroke induction, MRI revealed multifocal lesions in the cerebral cortex and subcortex such as T1 hypointensity, T2 hyperintensity, FLAIR hyperintensity, and diffusion-weighted hyperintensity in all 3 dogs. Upon postmortem examination, ischemic lesions were found to be consistent with the MRI findings and they were unstained with 2% triphenyltetrazolium chloride. Histologic features of the earliest neuronal changes such as cytoplasmic eosinophilia with pyknotic nuclei were identified. Neuropil spongiosis and perivascular cuffing were also prominently observed at the infarcted area. The present study demonstrated the features of MRI and histopathologic findings in canine ischemic stroke models.

We synthesized Fe-doped TiO2/α-Fe2O3 core-shell nanowires(NWs) by means of a co-electrospinning method anddemonstrated their magnetic properties. To investigate the structural, morphological, chemical, and magnetic properties of thesamples, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectronspectroscopy were used, as was a vibrating sample magnetometer. The morphology of the nanostructures obtained aftercalcination at 500oC exhibited core/shell NWs consisting of TiO2 in the core region and α-Fe2O3 in the shell region. In addition,the XPS results confirmed the formation of Fe-doped TiO2 by the doping effect of Fe3+ ions into the TiO2 lattice, which canaffect the ferromagnetic properties in the core region. For comparison, pure α-Fe2O3 NWs were also fabricated using anelectrospinning method. With regard to the magnetic properties, the Fe-doped TiO2/α-Fe2O3 core-shell NWs exhibited improvedsaturation magnetization(Ms) of approximately ~2.96emu/g, which is approximately 6.1 times larger than that of pure α-Fe2O3NWs. The performance enhancement can be explained by three main mechanisms: the doping effect of Fe ions into the TiO2lattice, the size effect of the Fe2O3 nanoparticles, and the structural effect of the core-shell nanostructures.

We apply differential affine velocity estimator (DAVE) to the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI) 12-min line-of-sight magnetograms, and separately cal- culate the injected magnetic helicity for the leading and the following polarities of nine emerging bipolar active regions (ARs). Comparing magnetic helicity ux of the leading polarity with the following polarity, we nd that six ARs studied in this paper have the following polarity that injected more magnetic helicity ux than that of the leading polarity. We also measure the mean area of each polarity in all the nine ARs, and nd that the compact polarity tend to possess more magnetic helicity ux than the fragmented one. Our results conrm the previous studies on asymmetry of magnetic helicity that emerging bipolar ARs have a polarity preference in injecting magnetic helicity. Based on the changes of unsigned magnetic ux, we divide the emergence process into two evolutionary stages: (1) an increasing stage before the peak ux and (2) a constant or decreasing stage after the peak ux. Obvious changes on magnetic helicity ux can be seen during transition from one stage to another. Seven ARs have one or both polarity that changed the sign of magnetic helicity ux. Additionally, the prevailing polarity of the two ARs, which injects more magnetic helicity, changes form the following polarity to the leading one.

This study were to perform for verifying the activation areas in the human's brain during mastication by using functional-MRI (f-MRI) device on the basis of hypothesis regarding anatomical-physiological parts of brain processing the information of motor and sensory function, and to perform further more for a providing basic provisional foundation about diagnosis, treatment and prognosis of abnormal occlusion as applying functional MRI. Generally healthy 10 volunteers who have a normal occlusion were selected. The half of members of volunteers was female. Age distributions were approximately alike. Before taking a f-MRI, sufficient practice was carried out as strict standards and made volunteers be not sensible to sweet taste of gum through chewing gum for 30 minutes before taking a f-MRI. Functional images for all volunteers were firstly obtained, and then anatomical images were next. The functional images consisted of echo-planar image volumes which were sensitive to BOLD (blood oxygenation level-dependent) contrast in axial orientation. The volume covered the whole brain with a 64×64 matrix and 42 slices. Images with 64 volumes were acquired under periodic mastication. The orofacial sensorimotor cortex was primary responsible cerebral part during mastication and insula. And also supplementary motor area and cerebellum in brain were intimately connected with mastication. Other numerous anatomical parts of brain were activated in each volunteer during mastication, but there was no statistical significance in this experiment. Differences according to gender and age were no significance in this study. The f-MRI device showed the accurate and detailed image in activation area of brain through valuable device. It suggested that f-MRI might be helpful to establish the basis of funtional standard occlusion depend on activation area of brain.

Indoor air quality including metro subway is of recent interests in large cities. Inflow air to the inside of the train and circulating air flow through MVAC of stations contain large amount of iron based fine particles. This paper evaluated the collection of such a dust by magnetic filters as comparing to conventional particle capturing mechanisms such as inertia, direct impaction and diffusion. It was found that filtration velocity, magnetic field intensity, and fiber size were the most important parameters for magnetic filtration. Application of magnetic force obviously enhances the collection efficiency particularly in fine modes smaller than 10 mm. However, its effect was found greater in 2.5 mm than submicron particles.

원자력이용시설에서 발생한 작은 크기의 금속 조각들을 효과적으로 제염하는 스마트 장치를 개발하였다. 이 장치는 자성연 마재를 포함한 영역의 자속밀도를 연속적으로 변화시키는 방법과 초음파를 이용하는 다중 제염장치이다. 한편, 제염 효율을 높이기 위해 제염 장치가 제염 대상 전체에 작용하도록 장치들의 구성을 수정하였다. 개발된 장치들의 최적 작동조건을 도 출하여 샘플로 선정한 소형의 금속방사성페기물에 대하여 자기장과 초음파제염을 각각 15분간 실시하였다. 그 결과 제염계 수의 범위는18~56으로 크게 향상되었으며 제염 후 모든 샘플은 백그라운드(BKG)값 이하로 확인되었다.

Magnetohydrostatic equilibria, in which the Lorentz force, the plasma pressure force and the gravitational force balance out to zero, are widely adopted as the zeroth order states of many astrophysical plasma structures. A magnetic flux-current surface is a surface, in which both magnetic field lines and current lines lie. We for the first time derive the necessary and sufficient condition for existence of magnetic flux-current surfaces in magnetohydrostatic equilibria. It is also shown that the existence of flux-current surfaces is a necessary (but not sufficient) condition for the ratio of gravity-aligned components of current density and magnetic field to be constant along each field line. However, its necessary and sufficient condition is found to be very restrictive. This finding gives a significant constraint in modeling solar coronal magnetic fields as force-free fields using photospheric magnetic field observations.