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 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.

현재 온실 내에서 진딧물류 등의 미소해충들의 피해가 늘어나고 있는 실정이다. 그러나 진딧물을 방제하기 위해 주로 화학적 방제제들이 이용되고 있어 약제 잔류독성 및 저항성 개체발생 등의 부작용이 발생하고 있다. 이러한 문제점을 극복하기 위해 최근 음파를 활용한 방제법이 연구된 바 있다. 과거 연구에서 100, 5,000, 10,000Hz 음파에 따라 진딧물의 섭식 행동의 유효한 차이가 나타난다는 결과를 바탕으로 이 중 100Hz 저주파로 진딧물에 음향 스트레스를 주어 번식률을 확인하였다. 고추에 발생하는 복숭아혹진딧물을 대상으로 하여 2015년 10월 9일부터 2015년 12월 18일까지 총 9회 반복실험을 진행하였다. 본 연구에서는 처리군과 대조군의 개체수를 분산분석(ANOVA) 통하여 통계적 유의미한 차이를 분석하여 그 결과를 제시하고자 한다.

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.

20 Hz 이하의 저주파 음은 해충 및 생물에게 스트레스를 발생시킬 수 있는 유해한 음으로 알려져 있다. 본 연구에서는 아메리카잎굴파리에 대한 저주파 음의 스트레스 효과를 조사하기 위하여 앰프 및 스피커(13 인치, 200 W)를 이용하여 사인파 20~1,000 Hz 구간의 순음을 절제된 아메리카잎굴파리 머리에 노출시켜 EAG 반응을 조사한 결과, 20 Hz 이하의 저주파 음에서만 EAG 반응이 나타났다. 또한 20 Hz 사인파 순음을 6시간 동안 조사하여 아메리카잎굴파리의 행동변화를 조사하였다. 행동 자료를 정보 엔트로피를 통해 분석한 결과, 엔트로피 지수는 처리 전의 경우 1.86이었으나 저주파 음을 처리한 후에는 1.42로 감소하였다. 본 연구를 통해 높은 음압의 저주파 음은 아메리카잎굴파리 방제에 활용할 수 있을 것으로 예상된다.

일본, 중국 등 인접 지진다발 국가에서 큰 지진동이 전파되어 오는 경우, Lg파가 최대 진폭을 갖게 되어 Lg파의 감쇠상수(Q-1)는 매우 중요한 의미를 갖게 된다. 지진연구협의회(IRIS)의 자료를 바탕으로 관측점간 경로거리가 긴 자료에 대하여 두관측점법을 이용하여 Lg파의 감쇠상수 값을 도출한 결과, 지진활동도에 상응하는 감쇠값을 얻었다. 일본지역을 잇는, 해양지각을 통과하는 경로는 높은 감쇠값을 보여서 지진활동도 및 지각의 감쇠특성을 잘 나타내고 있으며, 또한 큰 지진이 많았던 중국 상해지역을 잇는 경로도 일본지역 다음으로 높은 감쇠값을 보인다. 반면, 한반도 및 만주지역을 잇는 경로는 지진활동상황과 상응하는 매우 낮은 값을 보였다.

Ischemia that causes stroke induces inflammation of brain cells and apoptosis and as a result, it influences much on the functional part of a man. The needle electrode electrical stimulation (NEES) that combines acupuncture of oriental medicine with electric therapy of western medicine relieves inflammation of cells and has effect on regrowth of nerve tissues. This study was conducted to verify the influence of NEES on the occurrence of c-Fos of cerebrum after applying NEES to the meridian point, Zusanli (ST 36) of a rats with induced ischemia. Global ischemia was induced by using ligation method on common carotid artery of male Sprague Dawley (SD) rats. The ligation was maintained for 5 minutes and then suture was removed for blood reperfusion. After inducing global ischemia, NEES was done to the left and right meridian points of Joksamri of a rat for 30 minutes after 12 hours, 24 hours, and 48 hours. The findings were as follows. 1. In the result of immunohistochemical method, the number of c-Fos immune response cells significantly decreased (P<.05) in NEES group than the control group (GI) that did not get NEES. 2. In the result of western blotting, the occurrence of c-Fos after 24 hours from the inducement of ischemia significantly decreased (P<.05) in NEES group than the control group (GI) that did not get NEES. Therefore, as the effect of NEES was shown highest after 24 hours from the ischemia, it is suspected that NEES would take important role in early treatment after cerebral stroke.

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.

저주파소음(low frequency noise; LFN)은 인체의 다양한 기관과 정신적 상태에 영향을 미치며, 진동음향질환(vibroacoustic disease; VAD)같은 질병들을 야기 시킨다 이전의 연구에서는 인간 또는 설치류에서 VAD는 우울증 또는 불안장애와 같은 만성적인 정신 건강에 위험을 미친다고 보고되고 있다. 본 연구에서는 LFN이 스트레스의 신경생리적 반응에 미치는 영향을 규명하고자 하였다. 이를 위하여, LFN에 노출된 흰쥐에서 스트레스 반응에 중요한 역할을 하는 paraventricular nucleus of the hypothalamus(PVN)에서 초기발현유전자인 c-fos 양성세포 발현, locus coeruleus(LC)에서 NE 생성 효소인 tyrosine hydroxylase(TH) 양성세포 발현과 스트레스 호르몬의 농도를 측정하였다. LFN 집단은 각각 32.5Hz 와 125Hz를 하루에 4시간씩 이틀 동안 소음에 노출 하였으며, 정상집단은 소음에 노출되지 않도록 하였다. 저주파소음에 노출 후 집단 간 혈액내 코르티코스테론 분석과, 면역 조직염색법을 이용하여 스트레스에 반응하는 PVN에서 c-fos발현과, LC에서 TH를 분석한 결과, PVN에서는 c-fos 의 발현과 LC에서 TH의 발현이 증가됨을 관찰할 수 있었으며, 그리고 혈중 코르티코스테론의 농도 또한 LFN 집단에서 높게 발현됨을 확인 하였다. 그리고 32.5Hz보다 125Hz의 소음에서 면역염색반응과 코르티코스테론의 결과가 다소 높게 나타남을 알 수 있었다. 이러한 결과는 저주파소음에 의해 스트레스와 연관된 뇌의 부위에서 c-Fos와 TH의 발현이 증가됨을 증명하고 있다. 따라서 저주파소음은 일반적인 스트레스에 의한 반응과 비슷한 신경적 특징들을 보여주고 있다. 그리고 저주파소음에 의한 중추, 말초신경계의 활성화는 아마도 진동음향질환과 같은 행동장애 질병과 관련이 있을 것임을 시사한다.

In this paper, exposure levels of electromagnetic field were measured in residential environments and from appliances. First, the measurements of residential environments were taken in central locations in bedroom, living room, and kitchen in each home. Both arithmetic and geometric mean of normal-power condition are higher than low-power condition (all electrical devices turned off/unplugged), and the background fields in homes show a geometric mean of about 0.022 uT. Second, we measured broadband magnetic fields of domestic appliances at various distances. The highest magnetic field is 44.3 uT from the microwave oven, and the lowest is 1.4 uT from the Kimchi Refrigerator. The magnitude of magnetic fields from appliances dropped off at a rate inversely proportional to distance, but the ratio of drop-off on Korean appliances is lower than US and UK

The present study investigated the hypothesis that a extremely low frequency magnetic field (ELF-MF) partially suppresses the synthesis of human growth hormone (HGH) in a group of 28 primary schoolchildren living nearby and 60 primary schoolchildren aged 12 years living far away from overhead transmission power lines from December 2003 to April 2004 in Seoul, Korea. The mean personal exposure levels of the primary schoolchildren living nearby overhead transmission power line were 0.37 μT, whereas the levels for the primary schoolchildren living away from overhead transmission power line was 0.05 μT. From simple analyses, the mean growth hormone levels in the primary schoolchildren living nearby were lower than away from overhead transmission power line, and statistically significant differences in the levels of the growth hormone (p = 0.0316), whereas not statistically significant differences in the levels of the growth hormone related to the distance from residence to power line less and more than 100 m by cut-off point (p = 0.4017). In conclusion, these results may indicate that urinary levels of nocturnal growth hormone are altered in primary schoolchildren exposed to extremely low frequency magnetic field at overhead transmission power line.

In most tissues, apoptosis plays a pivotal role in normal development and in regulation of cell number. Therefore inappropriate apoptosis is revealed in a variety of diseases. This study was carried out to investigate the effects of acupuncture and needle electrode electrical stimulation on the change of caspase-3, 9 and neuronal nitric oxide synthase (nNOS) immunoreactive cells in the sprague dawley rats (SD rat). In immobilized SD rats (n=5), enhanced caspase-3 and caspase-9 expression were detected in the reticular part of substantia nigra, and enhanced nNOS was detected in the dorsolateral periaqueductal gray (DL-PAG) of midbrain and the paraventricular nucleus (PVN) of the hypothalamus using immunohistochemistry. Following the immobilization, acupuncture (n=5) and needle electrode electrical stimulation (n=5, 2 Hz) was applied at Hg (LI4) acupoint of SD rats, respectively. The stress-induced enhancement in the expression of caspase-3, 9 and nNOS were The present results demonstrate that and needle electrode electrical stimulation are effective in the modulation of expression of caspase-3, 9 and nNOS induced by immobilization.

Functional electrical stimulation (FES) training of the knee extensors is a useful way to rehabilitate the ability to stand and walk. However, training using FES has not been able to solve the problem of fatigue; clinical application of FES quickly produces muscle fatigue, due to the continuous activation of the muscles of the lower extremity. Therefore, reduction of muscle fatigue is an important factor in increasing the effectiveness of FES training in paraplegia. Intermittent high frequency alternating stimulation is a method that combines the advantages of high frequency (leading to strong muscle contractions) and alternating stimulation (reducing muscle fatigue), thereby continuously strengthening muscles. It is not known whether low frequency simultaneous stimulation results in stronger muscle contraction than high frequency alternating stimulation. This study compared the effectiveness of high frequency alternating stimulation with low frequency synchronized stimulation. Muscle power using FES on the quadriceps of 20 normal subjects were compared. Intermittent high frequency alternating stimulation did not produce more powerful muscle contraction than intermittent low frequency synchronized stimulation, because the muscle characteristics differed individually. Significant individual variation according to muscle characteristics was founded when applying FES. Accordingly, when physical therapists use FES to treat patients, they must be aware of individual variation in muscle characteristics.

제주 연안역에 있어서 수중 가청 저주파수음을 이용한 자원관리형 어업, 또한 어장에서 음향을 이용해서 어류를 유집할 수 있는 음향 어법 개발의 기초 자료를 얻기 위해 자리돔을 대상으로 측정 주파수 80∼800Hz의 수중음과 7V의 직류 전원의 전기 자극을 이용하여 육상 수조에서 조건 학습을 시킨 후 측정 주파수와 음압을 임의로 변화시켜 가면서 실험어 심전도를 도출하여 심박 간격의 변화로부터 청각 문턱치 곡선과 함께 백색 잡음에 의한 청각 임계비 및 청각 능력 지수를 조사한 결과는 다음과 같다. 자리돔의 청각 임계비는 측정 주파수 80Hz, 100Hz, 200Hz, 300Hz, 500Hz, 800Hz에서 음압이 각각 31dB, 35dB, 33dB, 23dB, 34dB, 41dB이고, 음압 73dB, 78dB, 83dB의 3단계 백색 잡음을 방성하였을 때 청각 문턱치는 백색 잡음이 없을 때보다 높게 나타나며 마스킹 효과가 측정 주파수 100Hz, 200Hz, 300Hz에서 보다 뚜렷하게 나타났다. 마스킹 현상은 약 음압 60∼65dB의 백색 잡음 레벨에서 나타나기 시작하였으나, 측정주파수 200Hz에서는 음압 57dB 이상에서, 측정주파수 800Hz에서는 73dB 이상의 백색 잡음 레벨에서 나타났으며 주파수 측정 주파수 300Hz에서 신호음을 인식하기 위해서는 대략 음압 88dB 이상과 함께 백색 잡음 레벨보다 음압 23dB 이상 높은 신호음이 요구되었으며 배경 잡음시 자리돔의 청각능력지수는 81로 나타났다.

A low frequency, high power hydroacoustic transducer with 7 tonpilz piston elements assembled in a circular array suitable for marine application, such as the transmission of underwater information and the development of new fisheries resources in the deep sea zone was designed. A modified Mason's model was applied to monitor and to simulate the transducer behavior at each step during the fabrication. The in air, and in water constructed tonpilz transducer was tested experimentally and numerically by changing the size and the type of the material for head, tail and acoustic window. Also, the developed transducer was excited by pulse signals and the received waveform was analyzed. The resonance peaks in the transmitting voltage response(TVR) of a single tonpilz element without housing were observed at 11.33kHz in air and 10.93kHz in air and 10.93 kHz in water, respectively, with the overall electrical-acoustic efficiency of 43.7%. The value of TVR of single tonpilz element with aluminum housing in water was 129.87dB re 1 μPa/V at 12.25 kHz with the frequency bandwith of 2.15 kHz and half beam angle of 30.2˚at -3dB.The resonance peaks in the transmitting voltage response of the 7 element circular transducer were observed at 11.50 kHz in air and 11.45 kHz in water, respectively. The value of TVR in water 144.84 dB re 1μPa/V at 11.5kHz with the frequency bandwith of 4.25 kHz and the half beam angle of 22.3˚ at -3dB.Reasonable agreement between the experimental measurements and the theoretical predictions for the directivity patterns, TVRs and the impedance characteristics of the designed transducer was achieved.

It is well known that fish hear a wide frequency range of sound using both laterial line and inner ear, and the sound is probably the most effective channel for long-range communication underwater than any other stimulus.The auditory threshold of svenband grouper, Epinephelus septem fasciatus was determined by conditioning method using a sound coupled with electric shock in a tank. The audio-signals and electric shock used in the experiment were pure tones of 100 to 1000Hz and DC 6n.The response of fish to the sound was observed by ECG intervals from precordial leads method (V1·V2 method). The auditory threshold curve for sevenband grouper was V-shaped, with most sensitive threshold at 350Hz in the range of 100~1000Hz. The Sevenband grouper were more sensitive to sounds of 200~400Hz than to adjacent frequencies.

대형 건축물의 진동과 같은 초저주파 진동특성의 해석을 수행하기 위해서는 측정대상 및 측정조건, 그리고 목적으로 하는 측정요소에 적합한 측정시스템이 구축되어야 하며, 구축된 측정시스템으로부터 얻어진 극히 제한된 유한량의 데이터로부터 목적하는 특성요소를 추출하기 위한 정밀한 데이터분석기술이 요구된다. 따라서, 본 연구에서는 고신뢰성을 저주파진동 특성의 분석을 위한 효과적인 데이터처리기법의 개발을 목표로, 측정조건에 따른 저주파진동 해석의 문제점을 분석하고, FFT법과 MEM법의 저주파응답 특성을 비교하였으며, 비교결과를 토대로 저주파진동 해석에 적합한 알고리즘을 결정하였다. 또한, 결정된 분석 알고리즘의 성능을 명확히 하여 정밀분석을 위한 측정데이터의 최적조건을 제시하였다.