Electric Probe Measurements at Edge Region During H‐Mode Discharges in KSTAR

Bak, J.G.,Oh, Y.S.,Kim, H.S.,Hahn, S.H.,Yoon, S.W.,Jeon, Y.M.,Xiao, W.W.,Ko, W.H.,Kim, W.C.,Kwak, J.G.,Woo, H.J.,Chung, K.S.,the KSTAR project team, WILEY‐VCH Verlag 2013 Contributions to plasma physics Vol.53 No.1

<P><B>Abstract</B></P><P>Electrical probe measurements are carried out at the scrape‐off‐layer (SOL) and divertor regions in order to investigate the characteristics of edge plasmas during H‐mode discharges in the Korea Superconducting Tokamak Advanced Research (KSTAR) device. Radial profiles of plasma parameters such as electron temperature T<SUB><I>e</I></SUB>, plasma density n<SUB><I>e</I></SUB>, and parallel flow velocity v<I><SUB>‖</SUB></I> are measured by using a fast reciprocating Langmuir probe assembly (FRLPA) at the SOL region. From the FRLPA measurements, it is found that the decay length of temperature λ<I><SUB>Te</SUB></I> and that of density λ<I><SUB>ne</SUB></I> are 2 <I>∼</I> 4 cm and 1 <I>∼</I> 3 cm, respectively. The magnitude of v<I><SUB>‖</SUB></I> near the last closed flux surface (LCFS) is 4 <I>∼</I> 15 km/s. The radial flux due to edge turbulence at the SOL region is investigated by using spectra analysis on electrostatic fluctuation levels such as ion saturation current Ĩ<I><SUB>is</SUB></I> and floating potential <TEX>$ \tilde{\rm V}_f$</TEX> obtained from the FRLPA measurement. The value of the flux is estimated as <I>∼</I> 10<SUP>20</SUP> particle m<SUP>−2</SUP> s <SUP>−1</SUP> near the LCFS. The poloidal distribution of the ion saturation current density j<I><SUB>is</SUB></I> is measured by fixed edge Langmuir probe array (ELPA) at the divertor region, and it is found that the positions of strike points from the ELPA measurement agree well with those reconstructed from the EFIT result using magnetic diagnostic data. From the spectrum analysis on the ELPA measurements at the divertor region during edge localized modes (ELMs) control in the H‐mode discharges, it is observed that the magnitude of <TEX>$ \tilde{\rm j}_{is}$</TEX>(<I>ω</I>) near strike point decreases when the ELMs are suppressed or mitigated (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

Key Features in the Operation of KSTAR

Jong-Gu Kwak,Oh, Y. K.,Kim, K. P.,Kim, S. W.,Hong, S. H.,Chu, Y.,Lee, H. J.,Kim, Y. O.,Kim, J.,Park, S. L.,Hahn, S. H.,Park, M. K.,Kim, H. K.,Bak, J. G.,Bae, Y. S.,Ko, W. H.,Lee, S. G.,Lee, J. H.,Jung IEEE 2012 IEEE transactions on plasma science Vol.40 No.3

<P>The Korea Superconducting Tokamak Advanced Research (KSTAR) device is aimed at advanced tokamak (AT) research. Three years have passed since it achieved its first plasma in 2008. Because it is a superconducting machine and is working toward AT research, it has unique features in terms of the machine engineering and operation. The toroidal field (TF) magnet coils are made of Nb<SUB>3</SUB>Sn, which provide high TFs up to 3.5 T, and have been fully tested. The poloidal field (PF) magnet coils, consisting of both Nb<SUB>3</SUB>Sn and NbTi, which have a maximum current of 25 kA in their design, were tested up to 15 kA. A thermal hydraulic analysis is being conducted for PF magnet coil operation. All plasma-facing components (PFCs) are equipped with water cooled graphite tiles and have the capability of being baked up to 350°C. A startup scenario, which considered both the effect of the ferromagnetic material in the cable in conduit conductor jacket of the magnet coils as well as a nonferromagnetic up-down asymmetry in the cryostat structure, was developed and demonstrated its effectiveness by the last two year's reliable operations. Passive stabilizers and in-vessel control coils (IVCCs) are key components to realize AT operation in KSTAR. The segmented IVCC coils were connected to form circular coils for internal vertical control in 2010, and diverted plasmas with high elongation (κ~1.8, δ>;0.6) were achieved. A neutral beam injection (NBI) system was developed aiming at 2 MW, 300 s per ion source which meets the long-pulse requirement of KSTAR. An NBI ion source with a power of 1.7 MW at 100 kV has been commissioned for 10 s. Finally, ELMy H-modes were successfully produced with 1.3-MW NBI power at a plasma current of 0.6 MA in the 2010 campaign. The first H-mode discharge (#4200) in KSTAR was achieved one year earlier than officially planned and was done at B<SUB>T</SUB> = 2 T with I<SUB>p</SUB> = 0.6 MA in a well-balanced double null configuration after boronization on the PFC. Successful operations in the early days of KSTAR including H-mode experiments revealed the capability of advanced and steady-state operation which is essential for the international thermonuclear experimental reactor (ITER) and future fusion reactors.</P>

처리방법별 농산물중의 잔류농약 제거에 관한 연구

박주성,강희곤,오준세,이규희,성창근,김성애,오만진 충남대학교 환경문제연구소 2000 環境硏究 Vol.18 No.-

The removal rates of pesticide residues on agricultural products by washing with tap water, washing with detergent, heating and dipping with ozonized water were analyzed. The removal rates of organophosphorous pesticide residues on perilla leaves and Korean cabbage were shown as 25.7-71.9% level by washing with tap water and 72.4%-82.0% level by washing with detergent. However, those on Angelica keiskei were shown as 44.6-64.7% level by washing with tap water and 72.4-82.0% by washing with detergent. Those on perilla leaves and Korean cabbage were shown as 61.1%-91.1% and 74.8-95.4% levels by heating, respectively. Also, the removal rates of organochlorine pesticide residues on perilla leaves and Aster scaber were shown as 55.6-66.3% level by washing with tap water, 85.8-93.0% level by washing with detergent and 54.1-63.6% level by heating. Therefore, the organochlorine pesticide residues was shown the highest removal rate by washing with detergent and not significance between washing with tap water and heating. When the grape was processed as jam, the removal rates of organophosphorous pesticide residues were shown as below 50% level and those of organochlorine were shown as 22.3-60.2% level with difference according to variety of pesticides. Also, the decomposition effects of pesticides by dipping in ozonized water were analyzed. The various solvents were tested for the most effective recovery of pesticides on agricultural products. The benzene contained 20% dichloromethane was shown the most effective recovery rate for organophosphorous pesticides as 105.4-113.8% level. Hexan was the most effective for organochlorine as 67.7-91.3% level. As the result by dipping with ozonized water, the changes of pesticide content levels according to dipping and dipping time in ozonized water were not shown significance.

Fast Reciprocating Probe Assembly for the KSTAR

Bak, J. G.,Lee, S. G.,KSTAR project team WILEY-VCH Verlag 2006 CONTRIBUTIONS TO PLASMA PHYSICS Vol.46 No.5

<P>A fast reciprocating probe assembly (FRPA) that can scan a distance of up to 32.5 cm with a maximum speed of 1.7 m/s was fabricated to obtain the spatial profile of basic plasma parameters in the edge region of the KSTAR plasma during a plasma discharge of 20 s. The probe driving mechanism consists of two parts; first a slow movement driven by a servo motor system and then a fast reciprocating movement actuated by a pneumatic system. A performance test of the drive system, which is remotely controlled by a PC, was carried out. The prototype of the probe head for the KSTAR FRPA was fabricated as a modular type for easy replacement. It was installed in the fast injection probe assembly (FIPA) in the Hanbit magnetic mirror device, and a radial plasma parameter profile measurement was carried out. The performance test results of the drive system and the profile measurements using the probe head are presented. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)</P>

一部 農村住民의 母子保健센타 施設分娩의 利用要園에 對한 豫備調査

박기흠,김병성,이종호,조홍준,김창엽,김정숙,허봉렬 의학교육출판사 1987 Korean Journal of Family Medicine Vol.8 No.3

^19F(p, αγ)^16O 반응의 α-γ 각상관

박상태,김기동,이대원,정운혁,노태익,정성채,이종환,나상균 동의대학교 기초과학연구소 1994 基礎科學硏究論文集 Vol.4 No.1

The α-γ angular correlations in the ^19F(p, αγ)^16O reaction have been measured using a 500 keV VDG accelerator at E_p=340 keV and a CaF₂ taget prepared by evaporation in vaccum. The measurement of the α-γ angular correlation between the α-rays from the decay of ^20Ne into ^16O and the γ-rays from ^16O has been performed using a Si surface barrier detector and a NaI(TI) detector to determine the spin of the 13.196 MeV level in ^20Ne, and those of the 6.14 MeV and the ground level in ^16O, together with the orbital angular momentum of the emitted α's. The α-γ angular correlations in the ^19F(p, αγ)^16O reaction have been also calculated for the assumed spins of the 13.196 MeV level in ^20Ne, and those of the 6.14 MeV and ground level in ^16O. The spins of the levels under condsideration have been determined by comparison of the calculated values with experimental value. The result makes a good agreement to Arnold's data.

Development of S - band Waveguide Valve for PLS 2 - GeV Linac

박주식(J. S. Bak),남궁원(W. Namkung) 한국진공학회(ASCT) 1995 Applied Science and Convergence Technology Vol.4 No.2

포항가속기연구소에서는 PIS 2-GeV 선형가속기 클라이스트론의 교체 및 보수시에 사용하기 위하여, 80 ㎿급 S-band의 도파관 밸브를 개발중에 있다. PLS형 도파관 밸브는 결합수단 없이 대전력을 전송할 수 있는 구조로 설계되어, 전력전송에 대한 제한을 받지 않는 특징을 갖는다. 본 도파관 밸브의 주요 구성부는 밀착구동체를 갖는 U자형 도파관부, 두개의 H-코너가 부착된 진공함, 그리고 두개의 Viton O-링이 장착된 진공기밀판으로 이루어져 있다. 시제품용 도파관 밸브의 특성조사 결과, 펄스폭 3.5 μsec, 반복율 30 ㎐에서 65 ㎿의 전략전송을 얻을 수 있었다. 본 논문에서는 PLS 도파관 밸브의 설계 개념, 기계적 특성 및 가공의 순으로 자세히 논할 것이며, 또한 현재까지의 실험결과 및 앞으로의 계획에 대하여 보고하기로 한다. Development of 80 ㎿ S-band waveguide valve is now under way at Pohang Accelerator Laboratory (PAL). It is intended to have easy replacement and quick maintenance for the PLS 2-GeV linac klystrons. We adopt a new design concept which removes a limitation on power transmission. This design is completely different from the traditional one. The new S-band waveguide valve consists of the V-shaped waveguide section with a pushrod assembly, a vacuum chamber with two H-corner sections and a sealing plate with two Viton O-rings. We have achieved a high power transmission of more than 65 ㎿ at a pulse width of 3.5 μsec and a pulse repetition frequency of 30 ㎐. It also shows an excellent reliability of the vacuum seal. We report here on the design considerations, the mechanical features, and the fabrication of our first waveguide valve, the results of our experiments so far, and some of our plans for the near future.

An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements.

King, J D,Strait, E J,Boivin, R L,Taussig, D,Watkins, M G,Hanson, J M,Logan, N C,Paz-Soldan, C,Pace, D C,Shiraki, D,Lanctot, M J,La Haye, R J,Lao, L L,Battaglia, D J,Sontag, A C,Haskey, S R,Bak, J G American Institute of Physics 2014 Review of scientific instruments Vol.85 No.8

<P>The DIII-D tokamak magnetic diagnostic system [E. J. Strait, Rev. Sci. Instrum. 77, 023502 (2006)] has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric '3D' fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 n 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic model predictions. Small 3D perturbations, relative to the equilibrium field (10(-5) < δB/B0 < 10(-4)), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit data acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ~500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 14 BP fluctuation sensors, with that measured by the upgraded B(R) saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.</P>

정신감정례에 대한 정신의학적 고찰

박희주,황선무 大韓神經精神醫學會 1973 신경정신의학 Vol.12 No.1

The authors recieved the data of psychiatric evaluation of 30 criminals who had been referred to determine criminal responsibility by the judicial authorities at the Pusan University Hospital. The obtained data were analyzed in respect to sex, age, education, occupation, contents of crimes, category of psychiatric disorder, criminal responsibility, and judicial decision. From the obtained results the authors could observe the followings. 1) Ninety percent of criminals was male. As to the age range the most stand between 31 and 40 years included almost all of them. Educationally half or over of them belong to the level of or belower the primary school course. 63.3% of criminals showed occupationally a person out of work. 2) In contents of crime, the most are murder and attempt murder which reveal relatively high value figuring 40% of the cases. 3) In category of mental illness the most are schizophrenia that consist of 40%. 4) Analysis done on the basis of criminal responsibility shows that those who were determined to be of no responsibility for their criminal behaviors are 63.3% and that those to be of responsibility are 36.7%. Most of those of no responsibility are schizophrenias.

Plastic 섬광검출기의 감마선 스펙트럼에 대한 unfolding 분석

김기동,박상태,최선수,이대원,정운혁,이종환,노태익 동의대학교 기초과학연구소 1995 基礎科學硏究論文集 Vol.5 No.1

The γ-ray pulse height spectra from ^137Cs and ^22Na were measured with a plastic scintillation detector for the unfolding analysis of the γ-ray spectra. The energy deposition spectra were calculated using the Compton deposition cross section. The energy dependent resolution and its corresponding response matrix were determined by comparing the measured γ-ray pulse height spectra with the calculated energy deposition spectra. The energy spectra were obtained by unfolding the measured pulse height spectra with the response matrix.