전기장에 의해 생성 된 진공 분극은 양자장에서 가상 전자-양전자 쌍의 재배열을 만든다. 그러나 정지 전하가 다른 장소로 이동할 때, 정지 전하에 의해 생성된 전기장은 사라질 것이다. 이때, 정지 전하에 의해 분극화된 가상 전자-양전자 쌍들은 같이 소멸된다. 가상 전자-양전자의 소멸 과정에서 가상 광자가 생성되는데, 이때 만들어지는 가상 광자들은 양자 전기 역학에서 자기력을 매개하는 광자가 된다. 이로 인하여, 전하의 이동은 자기장을 발생시키고, 전기장의 변화가 자기장을 생성하게 하는 원인이 된다.

The purpose of this study is to investigate the ELF-MF emissions from UCLs and to compare the ELF-MF emission levels of HVTLs and UCLs. In addition, this study proposes a method and management plan to investigate the effects of exposure to ELF-MF emissions from UCLs. The ELF-MF emissions from the 154 kV UCL were 15.4±24.4 (GM: 7.8)mG, while from the 345 kV line they were 6.0±2.4 (GM: 5.7)mG. Through the comparison between ELF-MF emissions of 154 kV UCL and HVTL, at about 20 m distance from an overhead line the emissions level is 4 mG, while from an underground line at about 10 m distance the emission level was recorded as less than 4 mG. Through comparing the ELF-MF emission amount of the UCL according to the burial method, it was found that the direct ELF-MF emission levels are 15.3±7.4 (GM: 13.9)mG at the direct point, in the conduit type 21.0±30.4 (GM: 10.8)mG, and in the buried form 8.5±12.3 (GM:5.1)mG. In this study, ELF-MF emissions were about 37.0% and 47.5% lower, respectively, compared with the direct power and conduit type. The correlation between ELF-MF emission (mG) and power load (A) was analyzed. The higher the power load, the higher the ELF-MF emission. The correlation between ELF-MF emission at the direct point and depth of the UCL was also analyzed, and it was found that as the depth of line burial increased, ELF-MF emissions decreased.

The curvature of spacetime represented by Einstein field equation has many physical implications, including gravity. As light is deflected by the curvature of spacetime, a magnetic field will also be influenced by the curved spacetime. A permanent magnet is generally known to maintain its persistent magnetic field on the ground as long as there is no external magnetic interference. However, a series of experiments find that there are noticeable changes in the magnetic fields distribution while the permanent magnet rotates. The magnetic field lines of the permanent magnet are deflected towards Earth’s centre, implying a possibility that we can use magnetic field, a more efficient tool than a satellite, to measure the curvature of spacetime. However, comparing the experimental results of this study with theoretically obtained values of the curvature of spacetime remains a vast area of research for future studies.

목 적：치아교정용 보철장치를 부착한 환자의 MRI 검사는 꾸준히 시행돼 오고 있다. 그러나 MRI 검사에서의 안전성에 대한 입증은 명확히 이루어지지 않고 있다. 이에 본 논문은 3.0T MRI에서의 자기장과 RF에 의한 치아교정용 보철장치와의 상호작용을 실제 임상 조건으로 실험하여 안전성을 입증하고자 한다. 대상 및 방법：3.0T MRI 장치와 광섬유 온도 측정계, 온도 측정용액, 치아교정용 보철장치를 사용하였으며, 자장에 의한 왜곡 실험은 편향각과 토크 측정 장치를 사용하여 측정하였으며, RF에 의한 발열 온도 측정은 wire와 bracket을 결합한 후 온도 측정용액에 담그고, 광섬유 온도계의 온도 센서를 치아교정용 보철장치와 그 주변부에 설치한 후 실제 임상 조건으로 실험하였다. 결 과：고정 자기장에 의한 편향각 측정에서 bracket은 5회 측정 평균 19.88ﾟ, Ni-Ti wire는 1.96ﾟ, stainless steel wire는 119ﾟ로 측정되었으며, torque 실험에서는 bracket과 Ni-Ti wire는 0점으로 no torque이었으며, stainless steel wire는 +4점으로 very strong torque로 측정되었다. RF 주파수인가로 인한 온도 변화는 Ni-Ti wire bracket에서는 임 상 조건 실험 시작 전 target 온도 21.8ﾟC에서 약 23분 34초간 측정하였을 때 22.2ﾟC로 약 0.4ﾟC 상승하였으며, 주변부 온도는 21.4ﾟC에서 22.4ﾟC로 약 1ﾟC 상승하였고, stainless steel bracket에서는 target 온도 23.5ﾟC에서 23.9ﾟC로 0.4 ﾟC, 주변부 온도는 23.4ﾟC에서 23.3ﾟC로 측정되었다. 결 론：본 연구의 실험을 통해 치아교정용 보철장치의 RF에 의한 발열 현상에 따른 온도 변화는 크지 않고, 주 자기장에 의한 영향은 치아교정 보철장치의 자화 감수성에 따라 크게 차이가 남으로써 주 자기장에 의한 치아교정용 보철장치의 치아 내 위치 변화가 발생할 가능성이 있음을 확인할 수 있었다.

The objective of this study was to investigate ELF-MF exposure levels of the elderly groups in their living environments using 24-hour personal measurement. In addition, EMF risk perception was investigated. Through evaluations of ELF-MF exposure levels in the proximity of the participants of 58 elderly groups, it was found that TWAam was 1.31 mG (TWAgm: 0.84). ELF-MF exposure levels of the elderly group that live in the proximity of a non-visible power line was high, but there were no statistically significant differences between the non-visible power line elderly group and visible power line elderly group. Moreover, there were no statistically significant differences in ELF-MF exposure according to gender, age, city classification, incomes, residence type, and size. The results showed that the perception of the ELF-MF was very low, as indicated by more than roughly 58.6% of the elderly surveyed saying that they did not know what ELF-MF was. In addition, there was no awareness among the group of how to avoid behavior of EMF from some electric equipment and facilities. Thus, these results will provide useful data for the determination of ELF-MF management and risk communication methods in the living environment for elderly people.

목 적 : 자기공명검사실 내 자기장을 측정하여 방사선사의 직업적 자기장 노출 정도를 산출한 후 주기적인 자기장 노출에 따른 발현 증상과 증상발현에 직접적으로 작용하는 영향 인자를 알아보고자 한다. 대상 및 방법 : 자기공명검사실에서 근무하는 방사선사 37명을 대상으로 일일 개인 자기장 노출정도와 그에 따른 증상을 선정하여 직업적 노출 관련 설문지를 작성한 후 주기적인 자기장 노출 시 발현 증상과 영향인자를 조사하였다. 개인 노출정도는 Tesla meter(EPRI, 3-axis matrolab THM-1176 PDA)를 이용하여 P1(panel), P2(upper table), P3(middle table), P4(lower table) 위치에서 자기장을 측정하였고, 검사실 내 방사선사의 행동유형을 4가지(이전 검사 정리 및 다음검사 준비(A), 스캔 전(B), 조영제 주입(C), 스캔 후(D)로 나누어 분석한 후 일일 개인 자기장 노출정도를 산출하였다. 측정 장비는 서울 소재 U병원의 자기공명영상장치(Avanto 1.5T, Skyra 3.0T, Achieva 1.5T, Achieva 3.0T, Ingenia 3.0T)를 측정하였으며, 직업적 노출 관련 설문지는 선행논문을 토대로 작성하였고, 설문은 일원배치분산분석으로 검증하였다. 결 과 : 자기장은 Ingenia 3.0T(P1=8670G, P2=15500G, P3=630G, P4=70G)에서 가장 높게, Achieva 1.5T(P1=2370G, P2=5480G, P3=230G, P4=20G)에서 가장 낮게 측정되었다. 방사선사의 행동유형은 A일 경우 P1=5sec, P2=18sec, P3=65sec, P4=55sec의 시간이 소요되었으며, B일 경우 P1=1min 12sec, P2=10sec, P3=18sec, P4=12sec, C일 경우 P1=14sec, P2=8sec, P3=30sec, P4=5sec, D일 경우 P1=12sec, P2=8sec, P3=39sec, P4=10sec의 시간이 소요되었다. 위 결과를 이용하여 개인노출정도를 산출한 결과 하루 평균 8명의 환자를 검사한다는 가정 하에 일일 94.8분으로 노출되었다. 이를 바탕으로 작성한 직업적 노출 관련 설문 결과 영향 인자 중 성별은 유의한 차이가 없었으며, 연령별과 근무년수별은 유의한 차이가 있었다. 영향 인자에 따른 유의한 발현 증상을 살펴보면 연령별에서는 흐린 시야(f=3.499, p=0.027)가 유의하였고, 근무년수별에서는 어지러움(f=2.969, p=0.046), 잘 안들림(f=5.298, p=0.006), 섬광(f=4.019, p=0.017), 두통(f=8.078, p=0.001), 피로(f=8.135, p=0.01), 집중력문제(f=3.608, p=0.025), 머리가 아찔함(f=3.808, p=0.021), 근육경련(f=4.067, p=0.017) 등이 유의하게 나타났다(p>0.005). 결 론 : 기존 선행 연구들에 따르면 고 자기장에 노출 될 경우 여러 가지 발현 증상이 나타난다고 보고하였는데 본 연구에서도 개인 노출 정도가 누적됨에 따라 이와 유사한 증상을 보였다. 현재 직업적 자기장 노출에 관한 연구는 미비한 실정이며, 특히 가장 높은 자기장에 주기적으로 노출되는 방사선사에 대한 연구는 전무한 실정이다. 즉 이러한 영향이 어떠한 작용을 하는지 밝혀지지 않고 있으며 향후 어떠한 위해로 나타날지 알 수 없다. 따라서 방사선사의 직업적 자기장 노출에 관한 체계적인 연구가 필요할 것으로 사료된다.

The processing properties of spent hen and broiler chicken were investigated before and after treatment to improve texture characteristics. Each treatment consisted steaming (S) with 85℃ for 20 min, Pulsed Electric Field (PEF) with 1.5 KV/cm for 4 sec, and Super Heated Steam (SH) with an oven temp. of 300℃, a steam temp. of 350℃ for 8 min. The yield of spent hen and broiler were 66.85% and 63.80% respectively in the control, but decreased in every treatment was lowest at 61.05% in the PEF treatment (p<0.05). In the color test, L value decreased, but the a and b values increased regardless of the species of spent hen or broiler. In the test of heating loss, the S treatment of spent hen had the highest result of 45.25% but lowest of 30.66% in the SH treatment of the broiler. When it was compared with various treatments, SH after PEF treatment showed the better result in terms of heating loss than the PEF or SH treatment respectively. In the test of texture, the broiler showed the lowest hardness of 5.57 kg in the SH (p<0.05). Otherwise, the spent hen resulted in 14.08 kg of hardness in steaming after PEF, but it improved significantly to 10.73 kg in SH after PEF. In the test of 9 scored sensory evaluation of overall palatability, 7.8 point was the best score with SH treatment in the broiler. The best score in spent hen was 6.3 point which was SH after PEF treatment. With this experiment, SH after PEF was the condition in the treatments to have the better texture of spent hen.

In this study, ELF-MF levels of subway trains were measured to understand the status of the intensity of ELFMF. The measurement points for the train are selected in the center of each train compartment(pantagraph compartment, motor-driven compartment and the compartment that is not connected to any other electric equipment) using EMDEX II. ELF-MF levels of trains were measured from the starting to the terminal station in each lines(Seoul line 1-9, Incheon line 1, Incheon international airport line, Gyungui line, Bundang line, Gyeongchun line, Joongang line, Suin line). We found that the mean and range of ELF-MF levels in the DC power subway train are 2.4 and 0.1~125.9 mG, respectively, while the mean and range of ELF-MF levels in the AC power subway train are 10.4and 0.0~156.3 mG, respectively. Furthermore, the maximum ELF-MF level(156.3 mG) was lower than the reference level(ICNIRP 833 mG, 60Hz). The findings of this study in relation to the characteristics of ELF-MF for subway will be useful to derive the ELF-MF exposure coefficient from our living environment in a subsequent study.

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.

Delayed onset muscle soreness (DOMS) is a painful condition that arises from e+M8xercise-induced muscle damage after unaccustomed physical activities. Various therapeutic interventions have been applied to reduce the intensity and duration of DOMS-related symptoms. Recently, pulsed electromagnetic field (PEMF) intervention has been introduced as an alternative noninvasive treatment for DOMS. This randomized, double-blind, placebo-controlled experiment was conducted to examine the effects of PEMF therapy on DOMS in elbow flexors at 24, 48, and 72 hours after the experimental DOMS induction. Thirty healthy volunteers ( yrs, cm, and kg) participated in this study. Each was randomly assigned to a PEMF or placebo group. On the first day, DOMS was induced in the elbow flexors by repeated isokinetic motions at low () and fast () speeds in all subjects. Thereafter, the PEMF group received 15-min daily treatment with a PEMF device. The placebo group received sham treatment of the same duration. Overall, PEMF application was more effective than the sham treatment in reducing the physiological symptoms associated with the DOMS including perceived soreness, median frequency, and electromechanical delay of the surface electromyography. In addition, median frequency and isokinetic peak torque of the PEMF group recovered to the pre-DOMS induction level earlier than the placebo group. In conclusion, this study suggests that PEMF can be applied as a new recovery strategy in reducing DOMS symptoms. Further experiments are required to examine the effect of the PEMF treatment on different types of exercise conditions and to determine the optimal treatment dosage and duration in a real clinical setting.

This study was performed to investigate the exposure levels of magnetic field (MF) in residences near electrical transformer rooms in apartment buildings in Korea. We determined that the location of transformer rooms in apartment buildings in Korea is not same as in other countries. In particular, in Korea, the transformer on the pole near buildings serves residential buildings of less than 5 floors. In the buildings taller than 5 floors transformers are often placed below the parking lots in the basement. We estimated that there were, however, about 85,000 with transformer room adjacent to an apartment and had identified about 1,600 apartment buildings with transformers that can be included in the TransExpos study. The mean value of measured MFs was 1.17 mG in apartments above transformer room and 0.97 mG in other floors from transformer room. This study was concluded that apartments in building with transformer room can be classified into high-exposure category based on their location in relation to transformer room.

Specific heat of a crystal is the sum of electronic specific heat, which is the specific heat of conduction electrons, and lattice specific heat, which is the specific heat of the lattice. Since properties such as crystal structure and Debye temperature do not change even in the superconducting state, the lattice specific heat may remain unchanged between the normal and the superconducting state. The difference of specific heat between the normal and superconducting state may be caused only by the electronic specific heat difference between the normal and superconducting states. Critical temperature, at which transition occurs, becomes lower than Tc0 under the influence of a magnetic field. It is well known that specific heat also changes abruptly at this critical temperature, but magnetic field dependence of jump of specific heat has not yet been developed theoretically. In this paper, specific heat jump of superconducting crystals at low temperature is derived as an explicit function of applied magnetic field H by using the thermodynamic relations of A. C. Rose-Innes and E. H. Rhoderick. The derived specific heat jump is compared with experimental data for superconducting crystals of MgCNi3, LiTi2O4 and Nd0.5Ca0.5MnO3. Our specific heat jump function well explains the jump up or down phenomena of superconducting crystals.

전기기기의 사용이 증가함에 따라 60Hz 전력선에서 발생되는 전자기장의 인체영향에 관한 관심이 고조되고 있다. 그와 더불어 60Hz 자기장에 의해 두통, 불면증 등 정신 신경 생리학적 증상을 호소하는 사람들이 증가하고 있다. 그러나 이러한 증상이 자기장 노출에 의한 것인지 심리적 요인 때문인지에 대하여 확실한 원인규명이 되어 있지 않다. 따라서 본 연구는 자기장 노출 시 생리학적 변화(심박수, 호흡수, 심박변이도, 뇌파의 알파, 베타파), 자각증상, 자기장 인지 여부를 동시에 측정하여 복합적으로 자각 증상 원인을 분석하는 연구를 수행하였다. 60Hz 12.5uT의 자기장을 일반인 군(16명)과 EHS 군(15명)을 대상으로 실제 노출 및 가상 노출을 하였다. 그 결과 알반인 군과 EHS 군 모두 60Hz 자기장 노출여부에 따른 생리학적 변화나 자각증상의 차이가 없었다. 또한 자기장 인지 정확도에서도 EHS 군이 일반인 군보다 인지를 잘한다고 볼 수 없었다. 그러므로 EHS 유발요인은 60Hz 자기장이 아니라 다른 심리적, 환경적 요인에 의한 것으로 사료된다.

The objective of this study was to evaluate Extremely Low Frequency Magnetic Fields (ELF-MFs) exposure level of housewives and the relation of residential environments with ELF-MFs exposure level in home. ELF-MFs measurements were performed for 58 housewives include 31 working women. Twenty-four hours personal MF exposure levels of housewives were slightly higher than working women as an arithmetic mean. However the median of 24 hours personal exposure levels for working women were significantly higher than housewives (p<0.05). The median of personal exposure levels due to the activity at home, working women were higher than housewives significantly (p<0.05). As a results of correlation of residential environments, such as their living environments, total income, type of water supply pipes, and distance from power line with ELF-MFs exposure level in home was different from the type of residence (p<0.05). This study could be informed as guidance for ELF-MFs exposure analysis in residential environment.