Journal of the Korean Society for Nondestructive Testing
/
v.30
no.4
/
pp.338-344
/
2010
A double rotation C-scanning system and a software program Under-Sodium MultiVIEW have been developed for the under-sodium viewing of a reactor core and in-vessel structures of a sodium-cooled fast reactor KALIMER-600. Double rotation C-scanning system has been designed and manufactured by the reproduction of double rotation plug of a reactor head in KALIMER-600. Hardware system which consists of a double rotating scanner, ultrasonic waveguide sensors, a high power ultrasonic pulser-receiver, a scanner driving module and a multi channel A/D board have been constructed. The functions of scanner control, image mapping and signal processing of Under-Sodium MultiVIEW program have been implemented by using a LabVIEW graphical programming language. The performance of Under-Sodium MultiVIEW program was verified by a double rotation C-scanning test in water.
Kim, Min Sun;Koo, Ho;Choi, Myung Ae;Moon, Se Jin;Yang, Seung Bum;Kim, Jae-Hyo
Korean Journal of Acupuncture
/
v.35
no.4
/
pp.187-202
/
2018
Objectives : Non-invasive transcranial electrical stimulation is one of therapeutic interventions to change in neural excitability of the cortex. Transcranial electro-acupuncture (TEA) can modulate brain functions through changes in cortical excitability as a model of non-invasive transcranial electrical stimulation. Some composites of fermented Scutellaria baicalenis (FSB) can activate intercellular signaling pathways for activation of brain-derived neurotrophic factor that is critical for formation of neural plasticity in stroke patients. This study was aimed at evaluation of combinatory treatment of TEA and FSB on behavior recovery and cortical neural excitability in rodent focal stroke model. Methods : Focal ischemic stroke was induced by photothrombotic injury to the motor cortex of adult rats. Application of TEA with 20 Hz and $200{\mu}A$ in combination with daily oral treatment of FBS was given to stroke animals for 3 weeks. Motor recovery was evaluated by rotating bean test and ladder working test. Electrical activity of cortical pyramidal neurons of stroke model was evaluated by using multi-channel extracellular recording technique and thallium autometallography. Results : Compared with control stroke group who did not receive any treatment, Combination of TEA and FSB treatment resulted in more rapid recovery of forelimb movement following focal stroke. This combination treatment also elicited increase in spontaneous firing rate of putative pyramidal neurons. Furthermore expression of metabolic marker for neural excitability was upregulated in peri-infract area under thallium autometallography. Conclusions : These results suggest that combination treatment of TEA and FSB can be a possible remedy for motor recovery in focal stroke.
International Journal of Naval Architecture and Ocean Engineering
/
v.12
no.1
/
pp.892-901
/
2020
We used a numerical method to estimate the hydrodynamic maneuvering derivatives for the heave-pitch coupling motion of an underwater glider. It is very important to assess the hydrodynamic maneuvering characteristics of a specific hull form of an underwater glider in the initial design stages. Although model tests are the best way to obtain the derivatives, numerical methods such as the Reynolds-averaged Navier-Stokes (RANS) method are used to save time and cost. The RANS method is widely used to estimate the maneuvering performance of surface-piercing marine vehicles, such as tankers and container ships. However, it is rarely applied to evaluate the maneuvering performance of underwater vehicles such as gliders. This paper presents numerical studies for typical experiments such as static drift and Planar Motion Mechanism (PMM) to estimate the hydrodynamic maneuvering derivatives for a Ray-type Underwater Glider (RUG). A validation study was first performed on a manta-type Unmanned Undersea Vehicle (UUV), and the Computational Fluid Dynamics (CFD) results were compared with a model test that was conducted at the Circular Water Channel (CWC) in Korea Maritime and Ocean University. Two different RANS solvers were used (Star-CCM+ and OpenFOAM), and the results were compared. The RUG's derivatives with both static drift and dynamic PMM (pure heave and pure pitch) are presented.
Kim, Jin Ha;Jung, Jae Sang;Hong, Seok Won;Lee, Chun Ju;Lee, Yong Guk;Park, Il Ryong;Song, In Haeng
Journal of Ocean Engineering and Technology
/
v.35
no.6
/
pp.446-456
/
2021
To build an environment facility of a large-scale ocean basin, various detailed reviews are required, but it is difficult to find data that introduces the related research or construction processes on the environment facility. The current generator facility for offshore structure safety evaluation tests should be implemented by rotating the water of the basin. However, when the water in the large basin rotates, relatively large flow irregularities may occur and the uniformity may not be adequate. In this paper, design and review were conducted to satisfy the performance goals of the DOEB through computational numerical analysis on the shape of the waterway and the flow straightening devices to form the current in the large tank. Based on this, the head loss, which decreases the flow rate when the large tank water rotates through the water channel, was estimated and used as the pump capacity (impeller) design data. The impeller of the DOEB current generator was designed through computational numerical analysis (CFD) based on the lift surface theory from the axial-type impeller shape for satisfying the head loss of the waterway and maximum current velocity. In order to confirm the performance of the designed impeller system, the flow rate and flow velocity performance were checked through factory test operation. And, after installing DOEB, the current flow rate and velocity performance were reviewed compare with the original design target values. Finally, by measuring the current velocity of the test area in DOEB formed through the current generator, the spatial current distribution characteristics in the test area were analyzed. Through the analysis of the current distribution characteristics of the DOEB test area, it was confirmed that the realization of the maximum current velocity and the average flow velocity distribution, the main performance goals in the waterway design process, were satisfied.
Space-borne Synthetic Aperture Radar(SAR) has been one of the most effective tools for monitoring quantitative oceanographic physical parameters. The Doppler information recorded in single-channel SAR raw data can be useful in estimating moving velocity of water mass in ocean. The Doppler shift is caused by the relative motion between SAR sensor and the water mass of ocean surface. Thus, the moving velocity can be extracted by measuring the Doppler anomaly between extracted Doppler centroid and predicted Doppler centroid. The predicted Doppler centroid, defined as the Doppler centroid assuming that the target is not moving, is calculated based on the geometric parameters of a satellite, such as the satellite's orbit, look angle, and attitude with regard to the rotating Earth. While the estimated Doppler shift, corresponding to the actual Doppler centroid in the situation of real SAR data acquisition, can be extracted directly from raw SAR signal data, which usually calculated by applying the Average Cross Correlation Coefficient(ACCC). The moving velocity was further refined to obtain ocean surface current by subtracting the phase velocity of Bragg-resonant capillary waves. These methods were applied to Envisat ASAR raw data acquired in the East Sea, and the extracted ocean surface currents were compared with the current measured by HF-radar.
Journal of Advanced Marine Engineering and Technology
/
v.38
no.7
/
pp.929-935
/
2014
This paper is study on the pressure monitoring system(PMS) for ship's engine performance analysis( SEPA) based on web, with high speed and accuracy. This system is composed of pressure sensor, monitoring module with multi channel A/D converter, TCP/IP and satellite internet communication system. Existing domestic products measure cylinder pressure when piston of first explosive cylinder reached TDC(the top dead center) point and then measure next cylinder pressure manually each angle divided by a constant rotating interval. But presented system monitors in the local and web computer, using pressure information transmitted from pressure sensor installed on each engine. In this system, it is possible to increase the accuracy of the engine performance analysis because not only each TDC points but cylinder pressures synchronized with the TDC points could be measured in real time, accurately. And therefore, it may be used in a various diagnosis of main engines, such as deviations of each cylinder maximum pressures(Pmax) and the TDC firing positions and combustion conditions.
Proceedings of the Korea Air Pollution Research Association Conference
/
2001.11a
/
pp.335-335
/
2001
Direct-normal, total horizontal and diffuse horizontal irradiance data obtained from a multi-filter rotating shadowband radiometer over seven different wavelength bands (416nm, 151nm, 616nm, 675nm, 870nm and 940nm and the entire spectrum) has been analyzed at Kwangju, South Korea from June 1998 December 2000. The maximum hourly global radiation flux ranged from 0.44 MJ/$m^2$ to 2.68 MJ/$m^2$ at around 11:00-12:00 Hr local time while the maximum hourly diffuse radiation flux ranged from about 0.96 MJ/$m^2$ to 1.37 MJ/$m^2$. The maximum hourly direct irradiance ranged from 1.42 MJ/$m^2$ to 2.92 MJ/$m^2$ from June1998-2000. During the period under consideration, the average monthly global radiation recorded were 13.09 MJ/$m^2$/day, 10.58MJ/$m^2$/day and 9.78MJ/$m^2$/day for years 1998, 1999 and 2000 respectively, while the diffuse irradiance were 6.54 MJ/$m^2$/day, 5.33 MJ/$m^2$/day and 5.14 MJ/$m^2$/day for f998, 1999 and 2000 respectively. The direct irradiance values at the site were 11.63 MJ/$m^2$/day, 8.24MJ/$m^2$/day and 7.75 MJ/$m^2$/day for 1998, f999 and 2000 respectively. It was observed that each of the years has its own unique meteorological parameters that affect the quality and quantity of radiation received for each month. The annual average daily fractions of the diffuse to the global radiation (KD) were 0.51, 0.61 and 0.59 for years 1998, 1999 and 2000 respectively. Analysis indicated that the average daily KD ranged from 0.13 to a maximum value of 0.99 in May for irradiance measured at the broadband channel while the maximum and minimum KD value of 0.91 and 0.23 was recorded at wavelength band 870nm and 940nm in January and September respectively. The lowest average daily clearness index (Kt) value recorded was 0.03 in May (Spring) and the annual average daily clearness indexes are 0.45, 0.34 and 0.35 for years 1998, f999 and 2000 respectively. The frequency of clear days annually at Kwangju is 67.95%, 29.57% and 40.72% for years 1998, 1999 and 2000 respectively.
Transactions of the Korean Society of Mechanical Engineers B
/
v.41
no.4
/
pp.293-301
/
2017
A Sub-kWe small-scale experimental test loop was manufactured to investigate characteristics of the supercritical carbon dioxide power cycle. A high-speed turbo-generator was also designed and manufactured. The designed rotational speed of this turbo-generator was 200,000 rpm. Because of the low expansion ratio through the turbine and low mass flowrate, the rotational speed of the turbo-generator was high. Therefore, it was difficult to select the rotating parts and design the turbine wheel, axial force balance and rotor dynamics in the lab-scale experimental test loop. Using only one channel of the nozzle, the partial admission method was adapted to reduce the rotational speed of the rotor. This was the world's first approach to the supercritical carbon dioxide turbo-generator. A cold-run test using nitrogen gas under an atmospheric condition was conducted to observe the effect of the partial admission nozzle on the rotor dynamics. The vibration level of the rotor was obtained using a gap sensor, and the results showed that the effect of the partial admission nozzle on the rotor dynamics was allowable.
Purpose: The purpose of this study was to develop a small animal PET using dual layer phoswich detector to minimize parallax error that degrades spatial resolution at the outer part of field-of-view (FOV). Materials and Methods: A simulation tool GATE (Geant4 Application for Tomographic Emission) was used to derive optimal parameters of small PET, and PET was developed employing the parameters. Lutetium Oxyorthosilicate (LSO) and Lutetium-Yttrium Aluminate-Perovskite(LuYAP) was used to construct dual layer phoswitch crystal. $8{\times}8$ arrays of LSO and LuYAP pixels, $2mm{\times}2mm{\times}8mm$ in size, were coupled to a 64-channel position sensitive photomultiplier tube. The system consisted of 16 detector modules arranged to one ring configuration (ring inner diameter 10 cm, FOV of 8 cm). The data from phoswich detector modules were fed into an ADC board in the data acquisition and preprocessing PC via sockets, decoder block, FPGA board, and bus board. These were linked to the master PC that stored the events data on hard disk. Results: In a preliminary test of the system, reconstructed images were obtained by using a pair of detectors and sensitivity and spatial resolution were measured. Spatial resolution was 2.3 mm FWHM and sensitivity was 10.9 $cps/{\mu}Ci$ at the center of FOV. Conclusion: The radioactivity distribution patterns were accurately represented in sinograms and images obtained by PET with a pair of detectors. These preliminary results indicate that it is promising to develop a high performance small animal PET.
We have observed dense core around young stellar objects, DR21, S140, Orion-KL, and L1551 using four millimeter-wave transitions of $HC_3N\;J$=4-3, J=5-4, J=10-9, and J=12-11. The spatial distribution of $HC_3N$ emission closely resembles the morphology of the previous CS observations that trace high density gas. These observations reveal the existence of $HC_3N$ dense cores around central IR source, elliptical in shape and almost perpendicular to the CO bipolar outflow axis. Small differences can be explained by that $HC_3N$ molecular line is more optically thin and is seen to be more detailed structure in the neighborhood of central IR sources. In S140 and Orion-KL, massive(${\sim}10\;M_{\odot}$), slowly rotating dense cores lie near at the central IR sources of bipolar outflows. The velocity channel maps of DR21 show that the bipolar outflow gas may have a correlation with the dense core of DR21. We analyzed intensities of the four lines to derive physical conditions in dense core from two methods, LTE and LVG. The column density of $HC_3N$, $N(HC_3N)$, between LTE and LVG calculations agree well with each other. The abundances of $HC_3N$ in each observing source have been estimated using the average values of $n(H_2)$ and $N(HC_3N)$ and assuming the size of dense core. The fractional $HC_3N$ abundances in massive dense cores of DR21, S140, and Orion-KL have a range of $(2-7){\times}10^{-10}$, while that of low mass dense core, L1551, has one order of magnitude greater value of $2{\times}10^{-9}$. This should be considered good agreement with the result by Morris et al.(1976). It may be considered that dense cores of DR21, S140, and Orion-KL may have almost same stage of chemical evolution, and their abundances have a small values relative to that of L1551. The column density $N(HC_3N)$ decreases with increasing distance from the densest part of the cloud, the central infrared source, and have the relation of $N(HC_3N){\varpropto}R^{\alpha}$, where a has a range of 0.65 to 0.89. The values of $n(H_2)$ are not varied with increasing distance from the dense core, and have almost same values. Therefore, it is considered that the dense cores in these regions probably consist of dense clumps in diffuse molecular gas medium, and $n(H_2)$ of each clump is ${\sim}10^5\;cm^{-3}$. Levels in the $T_{ex}$ increases with $n(H_2)$. It is considered that the $HC_3N$ dense cores are not completely thermalized. We examine the relationships between the luminosity of central infrared sources versus mass of the dense cores, and the luminosity of central infrared sources versus molecular hydrogen column density. Luminosities of the central IR sources show good correlation with mass and hydrogen column density of the dense core. Same has been found from CS observations. However, mass and size derived from $HC_3N$ observations are one order of magnitude smaller than those from CS. It can be interpreted that we see more central part of the cloud cores in $NC_3N$ lines than CS lines.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.