• 한국초전도ㆍ저온공학회논문지
• /
• 제15권2호
• /
• pp.20-23
• /
• 2013

For sensitive measurements of micro-Tesla nuclear magnetic resonance (${\mu}T$-NMR) signal, a low-noise superconducting quantum interference device (SQUID) system is needed. We have fabricated a liquid He dewar for an SQUID having a large diameter for the pickup coil. The initial test of the SQUID system showed much higher low-frequency magnetic noise caused by the thermal magnetic noise of the aluminum plates used for the vapor-cooled thermal shield material. The frequency dependence of the noise spectrum showed that the noise increases with the decrease of frequency. This behavior could be explained from a two-layer model; one generating the thermal noise and the other one shielding the thermal noise by eddy-current shielding. And the eddy-current shielding effect is strongly dependent on the frequency through the skin-depth. To minimize the loop size for the fluctuating thermal noise current, we changed the thermal shield material into insulated thin Cu mesh. The magnetic noise of the SQUID system became flat down to 0.1 Hz with a white noise of 0.3 $fT/{\surd}Hz$, including the other noise contributions such as SQUID electronics and magnetically shielded room, etc, which is acceptable for low-noise ${\mu}T$-NMR experiments.

• Korean Journal of Acupuncture
• /
• 제21권2호
• /
• pp.1-28
• /
• 2004

Objectives : Human physiological changes in the state of qigong has been measured using EEG(Electroencephalography), functional MRI(functional Magnetic Resonance Image), EAV(Electro-Acupuncture according to Voll) and SQUID(Superconducting Quantum Interference Device) measurements. Methods & Results : EEGs were measured to study the differences between Qigong masters and Qi receiver on the changes of EEG. During Qigong, an alpha waves were increased. The power spectra indicate that the peak frequency of alpha waves increased during Qigong. Qi receiver's EEG signals seemed to affected by the state of himself. Brain activation did not observed when qigong master concentrates the Qi at Laogong(P8). But a localization of fMRI signal in the sensory cortex was observed by electric acupuncture stimulation at Laogong(P8). Five phase deviation of EAV were clearly changed in the both cases of Qigong master and Qi receiver. When a Qigong master concentrates the Qi at Yintang, Laogong(P8), Qihai(CV6) meridian points during Qigong state, the change of magnetic field around acupoints Yintang, Laogong points has been measured using 40-Channel DROS-SQUID apparatus. After smoothing process of the continuously measured magnetic signal around acupoints for a few minutes, we could observe that a series of peaks, magnitude of -1.0~2.5pT appeared. But there was no significant difference in changes of magnetic signal around acupoints. Physical signals of magnetocardiogram has been measured by using 2-Channel DROS SQUID(Magnetocardiogram). Physical signals of magnetocardiogram were clealy changed at the ST segments after S-wave when qigong master concentrates the Qi.

• Progress in Superconductivity
• /
• 제4권1호
• /
• pp.42-47
• /
• 2002

Measuring magnetic fields with a SQUID sensor always requires preliminary adjustments such as optimum bas current determination and flux-locking point search. A conventional magnetoencephalography (MEG) system consists of several dozens of sensors and we should condition each sensor one by one for an experiment. This timeconsuming job is not only cumbersome but also impractical for the common use in hospital. We had developed a serial port communication protocol between SQUID sensor controllers and a personal computer in order to control the sensors. However, theserial-bus-based control is too slow for adjusting all the sensors with a sufficient accuracy in a reasonable time. In this work, we introduce programmatic control sequence that saves the number of the control pulse arrays. The sequence separates into two stages. The first stage is a function for searching flux-locking points of the sensors and the other stage is for determining the optimum bias current that operates a sensor in a minimum noise level Generally, the optimum bias current for a SQUID sensor depends on the manufactured structure, so that it will not easily change about. Therefore, we can reduce the time for the optimum bias current determination by using the saved values that have been measured once by the second stage sequence. Applying the first stage sequence to a practical use, it has taken about 2-3 minutes to perform the flux-locking for our 37-channel SQUID magnetometer system.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
• /
• 제8권4호
• /
• pp.450-456
• /
• 2002

오픈 소스 웹 관련 소프트웨어는 주로 UNIX 기반 운영체제 상에서 작동하며, 사용하는 운영체제에 따라 웹 시스템 전체의 성능에 영향을 미칠 수 있다. 본 논문에서는 운영체제가 웹 서비스를 얼마나 잘 지원하는 가를 분석하기 위해 소스 코드 수준의 시간 측정 도구를 만들고, 오픈 소스 웹 프록시 캐쉬 소프트웨어인 Squid가 요청하는 운영체제 시스템 호출의 수행 시간을 측정하였다. Squid는 2.4.STABLE1을 사용하였으며, 기반 운영체제로는 역시 오픈 소스인 Linux 2.4.2와 Solaris 8을 사용하여 시스템 서비스 성능 차이를 비교하였다. 이 결과 전체적으로 Squid를 지원하는 데에는 Linux 2.4.2가Solaris 8보다 나은 것으로 나타났다. 실험 결과는 오픈 소스 소프트웨어를 이용하여 웹 서비스를 구축하는 경우, 소프트웨어 선택을 위한 판단 자료로 사용될 수 있고, 웹 관련 소프트웨어를 지원하는 운영체제 서비스의 성능 개선을 위한 자료로도 유용하게 사용될 수 있다.

• 대한의용생체공학회:의공학회지
• /
• 제27권4호
• /
• pp.154-163
• /
• 2006

A 64-channel magnetocardiogram (MCG) system using low-noise superconducting quantum interference device (SQUID) planar gradiometers was developed for the measurements of cardiac magnetic fields generated by the heart electric activity. Owing to high flux-to-voltage transfers of double relaxation oscillation SQUID (DROS) sensors, the flux-locked loop electronics for SQUID operation could be made simpler than that of conventional DC SQUIDs, and the SQUID control was done automatically through a fiber-optic cable. The pickup coils are first-order planar gradiometers with a baseline of 4 em. The insert has 64 planar gradiometers as the sensing channels and were arranged to measure MCG field components tangential to the chest surface. When the 64-channel insert was in operation everyday, the average boil-off rate of the dewar was 3.6 Lid. The noise spectrum of the SQUID planar gradiometer system was about 5 fT$_{rms}$/$\checkmark$Hz at 100 Hz, operated inside a moderately shielded room. The MCG measurements were done at a sampling rate of 500 Hz or 1 kHz, and realtime display of MCG traces and heart rate were displayed. After the acquisition, magnetic field mapping and current mapping could be done. From the magnetic and current information, parameters for the diagnosis of myocardial ischemia were evaluated to be compared with other diagnostic methods.

• 한국식품과학회지
• /
• 제9권4호
• /
• pp.255-263
• /
• 1977

젓갈은 우리나라에서 옛부터 즐겨 먹어온 수산발효식품(水産醱酵食品)으로서 우리나라 고유(固有)의 젓갈이 많지만, 이에 대한 상세(詳細)한 연구보고(硏究報告)는 의외(意外)로 적다. 본(本) 실험(實驗)에서는 꼴뚜기젓의 정미성분(呈味成分)을 밝히기 위하여 선도(鮮度) 좋은 꼴뚜기를 원료(原料)로써 젓갈 숙성(熟成) 중의 핵산(核酸) 관련물질(關聯物質), 유리아미노산(酸), TMAO, TMA 및 betaine의 변화(變化)를 실험(實驗)하였다. 꼴뚜기젓 숙성(熟成) 중 ADP, AMP 및 inosine은 현저히 감소(減少)하는 반면(反面) hypoxanthine은 급증(急增)하여 숙성(熟成) 91일(日) 후(後)에는 건물량기준(乾物量基準) $9.3{\mu}mole/g$로서 원료(原料)에 비(比)하여 3.9배(倍) 증가(增加)하였다. 원료(原料)의 유리아미노산(酸) 조성(組成)을 보면, 함량(含量)이 많은 것은 Pro, Tau이고 다음이 Ala, Arg, Ser, Glu, Lys, Gly, Leu 및 Val이며, 함량(含量)이 적은 것은 Phe, Met. Tyr, Ileu, His의 순(順)이었다. 함량(含量)이 특(特)히 많은 아미노산(酸)의 전(全) 유리아미노산(酸)에 대한 비율(比率)을 보면, Pro 40.2%, Tau 32.0%로서 이들 2종(種)의 아미노산(酸)이 72.2%를 차지하였고, 엑스분질소(分窒素) 중 전(全)유리아미노산질소(酸窒素)가 차지하는 비율(比率)도 64.9%로서 높은 편이었다. 꼴뚜기젓 숙성(熟成) 중 유리아미노산(酸)의 양적(量的) 변화(變化)는 있으나 조성(組成)에는 변화(變化)가 없었다. 꼴뚜기젓의 유리아미노산(酸) 중 함량(含量)이 많은 것은 Pro, Leu, Lys, Ser, Arg, Ala, Val이고, Ileu, Phe, Met등도 상당히 많았으며, Glu, His등은 함량(含量)이 적었고 Tau과 Tyr은 흔적량에 불과(不過)하였다. betaine은 젓의 숙성(熟成)과 더불어 증가(增加)하기 시작하여 숙성(熟成) 91일(日)까지 증가(增加)하다가 그 후(後) 약간 감소(減少)하였다. TMAO는 숙성(熟成) 중 감소(減少)하는 반면(反面) TMA는 증가(增加)하였다. 63일간(日間) 숙성(熟成)시킨 꼴뚜기젓에는 건물량기준(乾物量基準)으로 TMAO질소(窒素)가 432.3mg%로서 상당히 많은 함량(含量)이었다. 꼴뚜기젓의 정미성분(呈味成分)으로서는 Pro, Leu, Ser, Lys, Arg, Ala, Val, Ileu, Phe, Met 및 Gly등과 같은 유리아미노산(酸)과 단맛을 가진 betaine, TMAO 그리고 핵산(核酸) 관련물질(關聯物質)로서는 hypoxanthine등이 중요(重要)한 정미성분(呈味成分)이라는 결론(結論)을 얻었다.

• 한국수산과학회지
• /
• 제34권5호
• /
• pp.563-569
• /
• 2001

1. 오징어 연골과 chitin, chitosan의 질소함량은 각각 $12.1\%,\;8.1\%,\;5.8\%$이며 회분함량은 각각 $0.8\%,\;9.4\%,\;0.2\%$로 나타났으며 오징어 연골로부터 최종적으로 만들어지는 chitosan의 수율은 $25\pm3\%$ 이었다. 2. 재탈아세틸화 하여 얻어진 chitosan의 탈아세틸화도는 $92\%$로 이는 NMR을 분석한 결과 chitin의 NMR 분석에서 보여지는 $CH_3$와 C=O기의 peak가 거의 나타나지 않았으며 또한 $C_3, C_5$가 $\beta-chitin$에서는 역평행 구조로서 2개의 signal로 나타나는데 본 실험에서는 $\beta-chitin$에서 보여지는 단일의 signal로 나타났다. 3. Chitosan을 0.2M AcOH-0.1 M AcONa 용액에 녹여 $30^{\circ}C$에서 점도를 측정한 결과 Mark-Houwink 식과 Rinaudo의 상수로부터 $[\eta]=1.424\times10^{-5}M^{0.96}$이었으며 분자량은 $1.15\times10^6$이었다. 4. I.R spectrum을 측정한 결과 chitin은 $1,653 cm^{-1}$에서amide I bend가 $1,558 cm^{-1}$에서 amide II bend가 나타났으며 chitosan은 $1,601 cm^{-1}$에서 1개의 넓은 bend가 생겼다. N-acetylchitosan의 경우 chitin과 마찬가지로 $1,655cm^{-1}$에서 amide I bend가 $1,560 cm^{-1}$에서 amide II bend가 나타났다. 5. 아세틸 함량은 N-acetylchitosan 분말이 $5.9\%$, acetylchitosan bead가 $63.2\%$ , N-ACF-1이 $56\%$ , N-ACF-2가 $58.7\%$ 이었다. 6. Chitin, chitosan 및 N-acetylchitosan을 formic acid에 용해하여 실온에서 시간에 따른 고유점도 변화를 관찰한 결과 chitosan이 chitin, N-acetylchitosan 보다 비교적 점도가 높았지만 3개 모두 시간이 지남에 따라 점도가 현저히 저하되어 25일째에는 chitosan이 14.39 dL/g, chitin이 1.31 dL/g, N-acetylchitosan이 1.06 dL/g이었다.

• 한국수산과학회지
• /
• 제31권1호
• /
• pp.26-30
• /
• 1998

본 연구는 1991년 2월부터 1992년 7월까지 한국 해역에 분포하는 오징어의 위내용물을 분석한 것이다. 위내용물의 종류를 살펴보면, 해조류, 갑각류, 두족류, 어류 외 동정 불가능한 것도 나타났다. 먹이생물중 어류를 가장 많이 먹었으며, 그 다음으로 두족류, 갑각류, 해조류 순으로 섭이하는 것으로 나타났다. 위의 만복도 조성에서 공위가 $58.00\%$이었고, 만복된 위는 $6.37\%$이었다. 여름과 가을 계군은 어류를 가장 많이 섭이한 반면, 겨울계군은 두족류를 매우 우점적으로 섭이하였다. 해조류와 갑각류는 세 계군 모두 매우 적은 양이 섭이되었다. 오징어의 주요 먹이생물은 어류이었고, 계군에 따른 위내용물의 차이는 없었다.

• 수산해양기술연구
• /
• 제22권3호
• /
• pp.8-16
• /
• 1986

The fishing conditions of flying squid, ommastrePhes barsram(Lesueur), in the North Pacific Ocean was studied based on the horizontal water temperature data, satellite data from NOAA and statistical data of flying squid fisheries which were collected from 1980 to 1984. The obtained results were as follows; 1. Since 1979, the Korean drift giIlnet fishery for flying squid was launched in North Pacific. Number of operating vessel and catch of flying squid increased gradually every year. The number of vessels were 111 and their annual catches were 42, 977 M/T in 1984. Therefore, Korean drift giIlnet fishery for this species has played an important role in the products of Korean high-sea fisheries. 2. In the beginning of the fisheries, fishing grounds was formed in the west of long. 1800E. In 1982, in consequence of the center which extended eastward, the fishing ground was formed long. 166$^{\circ}$W in the central North Pacific Ocean. Since 1983, the fishing grounds were formed as far as long. 161$^{\circ}$W. The range of general fishing season in the central North Pacific was from June to August. After september, fishing ground was shifted to the west, in the Northwestern Pacific. 3. The Predominant fishing season for the flying squid was August through January of the coming year. Optimum water temperature for flying sguid at surface layer in the Pacific Ocean ranged from 11 $^{\circ}$e to 17$^{\circ}$e in winter, 13$^{\circ}$e to 17$^{\circ}$e in spring, 12. 8$^{\circ}$C to 19.7$^{\circ}$e in summer and 1O.6$^{\circ}$e -18.7$^{\circ}$e in fall. 4. In summer, the Oceanographic condition in the North Pacific Ocean showed that the water temperature at surface layer was lower in 1980, 1983 and higher in 1981, 1982 and 1984 as compared with mean annual water temperature. 5. The characteristics df oceanographic conditions in the fluation, disformation, mixing and other factors of the Kuroshio and Oyashio currents, which have considerably influenced upon the water masses of the areas. 6. The data and information on surface thermal Structure interpreted from Infrared Satellite Imaginary from NOAA-7 and NOAA-8 are very available in estimating water temperature on the areas and investigating the major fishing grounds. 7. According to the fisheries statics of Japanese drift gilInet, the annual catches of flying squid considerably decreased from 225, 942 M/T in 1983 to 133, 217 M/T in 1984. 8. The fishing grounds in the central North Pacific in several fishing seasons were formed as follows: In June, the initial fishing season, the fishing grounds were formed in the vicinity of lat. 35 - 40oN, the central North Pacific east of 179$^{\circ}$E. In July, the fishing ground were formed in the wide arEa of the central North Pacific north of 400N and long. 174$^{\circ}$E-145$^{\circ}$W In Auguest, concentrative fishing operation carried out in :he central North Pacific north of 43$^{\circ}$N and East of 165$^{\circ}$W. On the other hand, in September, main fishing grounds were disappeared and moved to the west.

• 한국초전도학회:학술대회논문집
• /
• 한국초전도학회 2003년도 High Temperature Superconductivity Vol.XIII
• /
• pp.54-54
• /
• 2003