• Title/Summary/Keyword: L$^1$ 평면

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Study on the Improvement of Stow Net Fishing Technique and the Enlargement of Fishing Ground to the Distant Waters - 1 . Model Experiment of the Net - (안강망어법의 개량과 어장의 원해로의 확대를 위한 연구 - 1 . 어구의 모형실험 -)

  • Lee, Byoung-Gee;Kim, Jin-Kun;Lee, Ju-Hee
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.24 no.2
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    • pp.55-64
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    • 1988
  • Stow nets have widely been used in the western sea of Korea from the olden age. The original structure of a stow net is a large square-sectional bag net made of 4 netting panels, and the front fringes of top and bottom panels are connected to the top and bottom beams respectively. Wire ropes, which is originated from the holding anchor are gradually forked and biforked, and finally 4 pieces of wire rope (biforked pendants) are jointed to each beam. Much convenience caused by long and heavy beams were problemed, then some studies have been carried out to improve the net since 1930's. The most effective improvement were achieved in 1980 by Mr. Han and his colleagues. The key point of improvement was that the beams were removed and the belt shaped shearing device made by canvas was attached to the side panels, the head rope and ground rope to the front fringe of top and bottom panel, and biforked pendants are joined to the shearing device. Even though this is the epoch-making improvement of a stow net, the further study should be required to find out more effective method. The authors carried out a model experiment on the stow net to determine the vertical and horizontal opening of a net mouth, and also examine the front, top and side-view configuration of the net. The model net was constructed depending on the Similarity Law of Fishing Gear in 1/10 and 1/20 scale and set against to the current at shallow and speedy flowing channel. The vertical and horizontal openings were determined by using scaled bamboo poles, and the configuration was observed by using specially prepared observation platform and underwater observation glass, and also photographed by using specially prepared underwater photographic equipment. The results obtained can be summarized as follows: 1. The opening height and width of the shearing device varied in accordance with the relative length of the biforked pendants. Considering the height and width of shearing device in 6 cases of the arrangement system of biforked pendants, the best result was obtained in the case that the 2nd, 3rd and 4th pendents from the bottom-most was 5%, 9% and 4% longer than that. 2. On the top-view configuration the excessive deformation of head rope and ground rope were observed. In the actual net, 54m long head rope and ground rope were attached to the front fringe of top and bottom panels so that the head rope may be lifted to make the net mouth open highly. But actually the head rope and the ground rope are streamed backward without any lift, and also the netting followed the ropes were deformed until the 2/5 in the whole length of the net. This deformation may be guessed to disturb the entrance of fish school into the net and also caused the net to get caught by obstacles in the sea bed and to be broken largely. 3. Hydrodynamic resistance R of the actual net may be deduced as R(kg)=29.2$\times$103 v1.65. It is also expressed as R(kg)=5.9$\times$d/l$\times$ab v1.65. depending on the formula deduced by Koyama to estimate the resistance of trawl nets, where d/l denote the ratio between diameter of netting twine and length of mesh leg in every part of side panel, a and b, the stretched circumference of the mouth and the stretched length of the net, respectively.

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Simulation of mixing process and influence zone of the fresh water for the inner Saemankeum reservoir and outer region regarding seawater bypassing (해수소통이 전제된 새만금호 내부의 혼합확산거동과 외해역의 영향범위 모의)

  • Suh Seung Won;Mok In Kyun;Kim Jun Ho;Yu Kyung Sun
    • Proceedings of the Korea Water Resources Association Conference
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    • 2005.05b
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    • pp.543-547
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    • 2005
  • 해수소통을 전제한 경우 새만금호 내측의 염분변화가 만경강의 평수량 및 홍수량 유입에 따라 혼합확산되는 것을 평가하고 배수갑문 방류시 담수가 외해에 미치는 영향범위를 평가하기 위한 수치모형실험이 실시되었다. 이때 새만금호 내부의 관리수위는 DL=-1.5m, DL=-0.5m, DL=-0.0m, DL=+0.5m가 고려되었다. 외해역의 평가는 새만금을 포함한 전체해역에 대해 외해경계에서 4개의 주요분조($M_2,S_2,K_1,O_1$)의 진폭과 위상각을 대입하고 2차원 ADCIRC 및 3차원 TIDE3D 모형을 적용하였다. 내부는 여기에 3개 연직층을 고려한 3차원 ICM 모델이 추가 적용되었다. 내부의 혼합확산 평가 결과는 시간이 지남에 따라 외해에서 유입되는 염수가 상대적으로 저염인 담수호 내부로 유입 확산되는 것이 평면적으로나 연직방향으로 변화되는 것을 매우 뚜렷하게 나타남을 알 수 있고, 최소 1개월 이상 경과되어야 만경호측에 외해수가 혼합되는 것으로 분석된다. 수문을 개방하지 않은 상태에서 새만금 방조제 외해의 최강창낙조시 조류속도는 0.5-0.6m/s 정도에 해당되는 것으로 분석되었다. 신시갑문을 개방하는 경우 관리수위가 DL=-1.5m와 DL=+0.5m로 변함에 따라 갑문 전면 10Km-l3Km에 이르는 해역까지 수문개방에 따라 0.5m/s의 유속이 형성된다. 가력갑문을 개방하는 경우는 신시갑문의 개방에 따른 영향보다는 작지만 갑문 전면 14Km까지 0.5m/s의 강한 유동이 관리수위별로 나타나고 있다. 이러한 결과는 담수 방류로 인한 영향이 주기적으로 낙조시에 발생되어 새만금 방조제 전면의 해수순환과 유동에 적지 않은 영향을 미칠 개연성을 제시하는 것으로 해석된다.$\cdot$유출에 의한 수질변화양상을 단계적으로 구분하여 수질변화에 중요한 영향을 미치는 인자에 대한 이론적인 분석을 수행하고, 배수갑문 개방에 의한 수질개선효과를 최대화하기 위한 환경관리 방안 제시에 중점을 두어 수행하였다.ncy), 환경성(environmental feasibility) 등을 정성적으로(qualitatively) 파악하여 실현가능한 대안을 선정하였다. 이렇게 선정된 대안들은 중유역별로 검토하여 효과가 있을 것으로 판단되는 대안들을 제시하는 예비타당성(Prefeasibility) 계획을 수립하였다. 이렇게 제시된 계획은 향후 과학적인 분석(세부평가방법)을 통해 대안을 평가하고 구체적인 타당성(feasibility) 계획을 수립하는데 토대가 될 것이다.{0.11R(mm)}(r^2=0.69)$로 나타났다. 이는 토양의 투수특성에 따라 강우량 증가에 비례하여 점증하는 침투수와 구분되는 현상이었다. 경사와 토양이 같은 조건에서 나지의 경우 역시 $Ro_{B10}(mm)=20.3e^{0.08R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는 경사도가 증가할수록 증가하였으며 $10\% 경사일 때를 기준으로 $Ro(mm)=Ro_{10}{\times}0.797{\times}e^{-0.021s(\%)}$로 나타났다.천성 승모판 폐쇄 부전등을 초래하는 심

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Multi-Strata Lexikon vs. Constraintranking: Degemination im Deutschen (다층어휘부와 어휘부 대 제약우위도)

  • Yu Si-Taek
    • Koreanishche Zeitschrift fur Deutsche Sprachwissenschaft
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    • v.1
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    • pp.313-348
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    • 1999
  • 이 논문은 독일어의 겹자음회피현상을 설명함에 있어 어휘음운론에서의 분석이 보이는 문제들을 지적하고, 이 문제들이 제약에 바탕을 둔 이론에서는 어떻게 해결될 수 있는가를 보인다. 제약들간의 상호작용에서 특히 중요한 역할을 하는 것이 단일형태실현제약 (Uniform Exponence)으로서, 이 제약을 통해 독일어 동사의 현재시제, 단수, 2인칭 형태와 3인칭형태에서 나타나는 겹자음회피현상이 동사의 어형변화표 (Verbparadigma)와 밀접한 관련이 있음을 알 수 있다. 이는 규칙들을 통해 2인칭과 3인칭의 올바른 형태를 각각 개별적으로 찾아내는 어휘음운론의 분석과는 근본적으로 다르다. 왜냐하면 어휘음운론의 분석에 따를 때, 예를 들어 3인칭 동사 arbeitet에서 Schwa 모음의 삽입은 겹자음회피를 위해 일어난다고 설명되지만 겹자음이 없음에도 불구하고 Schwa 모음이 마찬가지로 삽입되는 2인칭동사 arbeitest는 설명되지 않기 때문이다. 이런 분석에서는 2인칭 형태와 3인칭 형태가 서로 아무런 관련 없이 각기 따로 존재하게된다. 이에 반해 단일형태제약은 이 두개의 형태를 동시에 비교하므로, 동사 굴절형태에서 마치 불필요한 것으로 보이는 모음삽입이나 자음탈락의 원인에 대해 이론적인 근거를 제시할 수 있다. 즉 2인칭 형태와 3인칭 형태는 보다 상위의 제약들이 막지 않는 한 서로 최대한 비슷한 형태를 가지려고 한다. 이 논문은 겹자음 회피를 위한 수단으로서 모음삽입이나 자음탈락은 오로지 이를 통해 동사의 어형변화표가 좋아질 때만 가능하다는 것을 보여줌으로써 규칙이론이 포착하지 못하고 있는 중요한 일반화를 제시하고 있다. 단일형태 실현제약의 중요성은 접두사 in- 과 un- 이 어간과 결합할 때 보이는 대조를 통해서도 확인된다. 여기서도 어휘음운론의 다층어휘부 구조에 의한 설명이 갖는 문제점이 제약들간의 상호작용을 통해 해결될 수 있음을 알 수 있다.VII-1 및 VII-2공의 3600 m 하부층은 건성 가스 생성 단계에까지 도달한 것으로 나타났다. JDZ VII-1, VII-2 시추공의 3500 m 하위 구간의 올리고세 퇴적층에서 유기물 함량 및 수소 지수가 급격히 감소하는 것은 매몰 심도가 깊어지면서 유기물이 열 분해되어 이미 탄화수소를 생성한 것으로 해석된다. JDZ VII-1 및 VII-2 시추공의 가스징후 및 길소나이트 (gilsonite)는 탄화수소가 생성되어 이동한 흔적을 시사한다.을 해석할 수 있음을 보여주는 것으로 평가된다. 다만 PLAYMAKER2가 보다 신뢰할 만한 퇴적환경 해석을 위한 전문가 시스템으로 구축되기 위해서는 향후 많은 퇴적학 전문가들이 추가로 참여하여 기존 규칙들을 재검증하고 새로운 규칙들을 첨가함으로써 보디 세련된 지식베이스를 개발하여야 할 것으로 판단된다.이며 세 개의 산소가 이루는 평면에서 $1.68{\AA}$ 소다라이트내로 이동하여 위치한다. 32개의 $Tl^{+}$ 이온은 결정학적 자리 II에 존재하고 있으며 산소와의 결합거리를 $2.70(1){\AA}$을 유지하면서 큰 동공속으로 $1.48{\AA}$ 이동하여 위치한다. 약 18개의 $Tl^+$ 이온은 결정학적 자리III에, 또 다른 10개의 $Tl^+$ 이온은 결정학적 자리III'에 존재하고 골조 산소와 각각 $2.86(2){\AA},\;2.96(4){\AA}$의 결합거리를 이룬다.

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The Crystal Structure of Bis(1,2-diaminopropane)palladium(Ⅱ) Bis(oxalato)palladate(Ⅱ) (Bis(1,2-diaminopropane)palladium(Ⅱ) Bis(oxalato)palladate(Ⅱ)의 결정구조)

  • Kim Sei Hwan;NagGung Hae;Jeon, Ho Jung
    • Journal of the Korean Chemical Society
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    • v.37 no.6
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    • pp.599-603
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    • 1993
  • Crystal structure of bis(1,2-diaminopropane)palladium(II) bis(oxalato)palladate(II) has been determined by X-ray crystallography. Crystal data: $Pd_2C_{10}H_{10}N_{4}O_{8}$, $M_W$ = 573.09, orthorhombic, space group $P_{ccn}$ (No = 56), a = 16.178(5), b = 16.381(6), c = 6.685(2)$\{AA}$, V = 1771.6 $\{AA}^3$, $M_W$W = 573.09, $D_c$ = 2.014 g${\cdot}c\;m^{-3}$, Z = 4, T = 294K, F(000) = 1056.0 and $\mu$ = 20.466 c$m^{-1}$. The intensity data were collected with $Mo-K\alpha$ radiation (${\lambda}$ = 0.7107 $\AA)$ on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by Patterson method and refined by full matrix least-squares methods using Pivot weights. The final R and S values were R = 0.065, $R_W = 0.059, R_{all}$ = 0.065 and S = 4.315 for 605 observed reflections. Both cation and anion complexes are essentially planar and have dihedral angle of $18(l)^{\circ}$ between thier planes. In the crystal structure, they do not have the Magnus's salt type mixed stacks; instead, the complex anions form regular stacks along the c-axis with the M-M bond length of $3.343(5)\AA$ and their stacks are surrounded by the complex cations through hydrogen bonds with the nitrogen-oxygen distances of 2.94(3) and $3.31(4)\AA.$

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On the vibration influence to the running power plant facilities when the foundation excavated of the cautious blasting works. (노천굴착에서 발파진동의 크기를 감량 시키기 위한 정밀파실험식)

  • Huh Ginn
    • Explosives and Blasting
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    • v.9 no.1
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    • pp.3-13
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    • 1991
  • The cautious blasting works had been used with emulsion explosion electric M/S delay caps. Drill depth was from 3m to 6m with Crawler Drill ${\phi}70mm$ on the calcalious sand stone (soft -modelate -semi hard Rock). The total numbers of test blast were 88. Scale distance were induced 15.52-60.32. It was applied to propagation Law in blasting vibration as follows. Propagtion Law in Blasting Vibration $V=K(\frac{D}{W^b})^n$ were V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W : Maximum charge per delay-period of eight milliseconds or more (kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents where the quantity $\frac{D}{W^b}$ is known as the scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagorized in three groups. Cubic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge Per delay Plots of peak particle velocity versus distoance were made on log-log coordinates. The data are grouped by test and P.P.V. The linear grouping of the data permits their representation by an equation of the form ; $V=K(\frac{D}{W^{\frac{1}{3}})^{-n}$ The value of K(41 or 124) and n(1.41 or 1.66) were determined for each set of data by the method of least squores. Statistical tests showed that a common slope, n, could be used for all data of a given components. Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom over loom distance because the frequency is verified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m ------- under l00m ${\cdots\cdots\cdots}{\;}41(D/sqrt[2]{W})^{-1.41}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}A$ Over 100m ${\cdots\cdots\cdots\cdots\cdots}{\;}121(D/sqrt[3]{W})^{-1.66}{\;}{\cdots\cdots\cdots\cdots\cdots}{\;}B$ where ; V is peak particle velocity In cm / sec D is distance in m and W, maximLlm charge weight per day in kg K value on the above equation has to be more specified for further understaring about the effect of explosives, Rock strength. And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

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Study on the Physical and Mechanical Properties of Particleboard and Oriented Strandboard Manufactured by Tulliptree (Liriodendron tulipifera L.) (백합나무를 이용하여 제조한 3층 파티클보드와 배향성 스트랜드보드(OSB)의 물성에 관한 연구)

  • Seo, Jun won;Gang, Gil woo;Jo, Gun hee;Park, Heon
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.1
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    • pp.67-72
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    • 2018
  • This study was conducted to investigate a potential of Yellow poplar (Liriodendron tulipifera L.) as a raw material for the manufacturing of particleboard (PB) and oriented strandboard (OSB). PB panels were prepared at the parameters of $0.7g/cm^3$ density, 15 mm thickness, three-layer, $E_1$ grade urea-formaldehyde (UF) resin, emulsion wax, and hardener. OSB panels were manufactured with a density of $0.65g/cm^3$, thickness of 10 mm, and $E_1$ grade of UF resin. Particle size of the face layer of PB was 20~80 mesh with 7~9% moisture content (MC), while that of core-layer was 3~20 mesh with 3~5% MC, which was similar to the production condition of commercial PB. As a result, the manufactured PB panels with 15.8 mm thickness, $0.7g/cm^3$ density, and 5.8% MC satisfied the requirement of bending strength of 15 type PB of Korean Industrial Standard (KS F 3104). Both internal bonding (IB) strength and surface screw withdrawal resistance also satisfied the requirement of 18 type PB of the standard. But, the edge screw withdrawal resistance satisfied the requirement of 15 type PB of the standard. These differences in properties could be due to the slenderness ratio of raw particles. In case of OSB panels with 10.7 mm thickness, $0.68g/cm^3$ density, and 5.8% MC satisfied all the requirements of bending strength, screw withdrawal resistance, and IB strength of 18 type PB of the standard. These results suggest that Yellow poplar wood has a good potential as a raw material for the production of PB and OSB.

Flow Resistance and Modeling Rule of Fishing Nets 4. Flow Resistance of Trawl Nets (그물어구의 유수저항과 모형수칙 4. 트롤그물의 유수저항)

  • KIM Dae-An
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.30 no.5
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    • pp.691-699
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    • 1997
  • In order to find out the properties in flow resistance of trawlR=1.5R=1.5\;S\;v^{1.8}\;S\;v^{1.8} nets and the exact expression for the resistance R (kg) under the water flow of velocity v(m/sec), the experimental data on R obtained by other, investigators were pigeonholed into the form of $R=kSv^2$, where $k(kg{\cdot}sec^2/m^4)$ was the resistance coefficient and $S(m^2)$ the wall area of nets, and then k was analyzed by the resistance formular obtained in the previous paper. The analyzation produced the coefficient k expressed as $$k=4.5(\frac{S_n}{S_m})^{1.2}v^{-0.2}$$ in case of bottom trawl nets and as $$k=5.1\lambda^{-0.1}(\frac{S_n}{S_m})^{1.2}v^{-0.2}$$ in midwater trawl nets, where $S_m(m^2)$ was the cross-sectional area of net mouths, $S_n(m^2)$ the area of nets projected to the plane perpendicular to the water flow and $\lambda$ the representitive size of nettings given by ${\pi}d^2/2/sin2\varphi$ (d : twine diameter, 2l: mesh size, $2\varphi$ : angle between two adjacent bars). The value of $S_n/S_m$ could be calculated from the cone-shaped bag nets equal in S with the trawl nets. In the ordinary trawl nets generalized in the method of design, however, the flow resistance R (kg) could be expressed as $$R=1.5\;S\;v^{1.8}$$ in bottom trawl nets and $$R=0.7\;S\;v^{1.8}$$ in midwater trawl nets.

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A Study on the Propagation Path Considering the Horizontal Alignment of Road (도로의 평면선형을 고려한 전파경로 분석)

  • Kim, Song-Min
    • 전자공학회논문지 IE
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    • v.44 no.1
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    • pp.27-32
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    • 2007
  • This study was to suggest the predictive model of propagation, considering the effect by the multipath waves produced by the sending and receiving vehicles' left/right reflectors and the adjacent vehicles when the communication between the vehicles on the one-way two-lanes road in the urban city with a lot of traffic jams. Then, the radius of curved road was 600[m], the length of curved roads $52.4\sim471.2[m]$, and the bridge's pier of road was $5o\sim45o$. Also, it was simulated by changing the receiving vehicle located on the curved road's gap from minimum 3.3[m] to maximum 29.5[m], corresponding to the change of distance of the bridge's pier of road and curved road. As a result of this research above, in case of $5o\sim15o$ bridge's pier of road, it was within l[dB] regardless of the receiving vehicle's position on the curved road in case of propagation path loss. In case of $15o\sim45o$, it was approximately $1\sim8[dB]$ as the bridge's pier of road is changed. And, in case of propagation path, it found out that it was changed to $0.4\sim120[m]$ according to the change of bridge's pier of road. Then, the delay time of propagation was 400[nsec] as it produced 120[m] in the difference of propagation path.

Crystal Structures of Dehydrated Partially $Sr^{2+}$-Exchanged Zeolite X, $Sr_{31}K_{30}Si_{100}A1_{92}O_{384}\;and\;Sr_{8.5}TI_{75}Si_{100}AI_{92}O_{384}$ (부분적으로 스트론튬이온으로 교환되고 탈수된, 제올라이트 X의 결정구조)

  • Kim Mi Jung;Kim Yang;Seff Karl
    • Korean Journal of Crystallography
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    • v.8 no.1
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    • pp.6-14
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    • 1997
  • The crystal structures of $Sr_{31}K_{30}-X\;(Sr_{31}K_{30}Si_{100}A1_{92}O_{384};\;a=25.169(5) {\AA}$) and $Sr_{8.5}Tl_{75}-X (Sr_{8.5}Tl_{75}Si_{100}A1_{92}O_{384};\;a=25.041(5) {\AA}$) have been determined by single-crystal X-ray diffraction techniques in the cubic space group $\=F{d3}\;at\;21(1)^{\circ}C$. Each crystal was prepared by ion exchange in a flowing stream of aqueous $Sr(ClO_4)_2\;and\;(K\;or\;T1)NO_3$ whose mole ratio was 1 : 5 for five days. Vacuum dehydration was done at $360^{\circ}C$ for 2d. Their structures were refined to the final error indices $R_1=0.072\;and\;R_w=0.057$ with 293 reflections, and $R_1= 0.058\;and\;R_w=0.044$ with 351 reflections, for which $I>2{\sigma}(I)$, respectively. In dehydrated $Sr_{31}K_{30}-X,\;all\;Sr^{2+}$ ions and $K^+$ ions are located at five different crystallographic sites. Six-teen $Sr^{2+}$ ions per unit cell are at the centers of the double six-rings (site I), filling that position. The remaining 15 $Sr^{2+}$ ions and 17 $K^+$ ions fill site II in the supercage. These $Sr^{2+}$ and $K^+$ ions are recessed ca $0.45{\AA}\;and\;1.06{\AA}$ into the supercage, respectively, from the plane of three oxygens to which each is bound. ($Sr-O=2.45(1){\AA}\;and\;K-O=2.64(1){\AA}$) Eight $K^+$ ons occupy site III'($K-O=3.09(7){\AA}\;and\;3.11(10){\AA}$) and the remaining five $K^+$ ions occupy another site III'($K-O=2.88(7){\AA}\;and\;2.76(7){\AA}$). In $Sr_{8.5}Tl_{75}-X,\;Sr^{2+}\;and\;Tl^+$ ions also occupy five different crystallographic sites. About 8.5 $Sr^{2+}$ ions are at site I. Fifteen $Tl^+$ ions are at site I' in the sodalite cavities on threefold axes opposite double six-rings: each is $1.68{\AA}$ from the plane of its three oxygens ($T1-O=2.70(2){\AA}$). Together these fill the double six-rings. Another 32 $Tl^+$ ions fill site II opposite single six-rings in the supercage, each being $1.48{\AA}$ from the plane of three oxygens ($T1-O=2.70(1){\AA}$). About 18 $Tl^+$ ions occupy site III in the supercage ($T1-O=2.86(2){\AA}$), and the remaining 10 are found at site III' in the supercage ($T1-O=2.96(4){\AA}$).

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Detection for Residual Thyroid Tissue and Metastatic Lesion after Total Thyroidectomy in Patients with Differentiated Thyroid Cancer: Comparison between Tc-99m Pertechnetate Sean and High Dose I-131 Therapy Sean (분화 갑상선암 환자의 수술후 잔여갑상선조직 및 전이병소의 진단: Tc-99m Pertechnetate 스캔과 고용량 옥소 치료 후 I-131 스캔의 비교)

  • Lee, Joo-Ryung;Ahn, Byeong-Cheol;Jeong, Shin-Young;Lee, Jae-Tae;Lee, Kyu-Bo
    • The Korean Journal of Nuclear Medicine
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    • v.37 no.2
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    • pp.120-127
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    • 2003
  • Purpose: To evaluate diagnostic sensitivity of nuclear imaging in the detection of residual thyroid tissue and metastatic lesion, we have compared neck scintigrams with Tc-99m pertechnetate (Tc-99m scan) and high dose I-131 iodide (I-131 scan) in patients with differentiated thyroid cancer. Subjects and Methods: One hundred thirty-five thyroidectomized patients for differentiated thyroid cancer were enrolled in this study. Twenty-three had a previous history of radioiodine therapy. Planar and pin-hole images of anterior neck with Tc-99m were acquired at 20 minutes after injection, followed by I-131 scan three days after high-dose radioiodine therapy within 7 days interval. Patients were asked to discontinue thyroid hormone replacement more than 4 weeks. Results: All subjects were in hypothyroid state. Seventy out of 135 patients (51.9%) showed concordant findings between Tc-99m and I-131 scans. I-131 scan showed higher number of uptake foci in all of 65 patients showing discordant finding. Tc-99m scan showed no thyroid bed uptake in 34 patients, whereas 23 of them (67.6%) showed bed uptake in I-131 scan. Tc-99m scan did not show any uptake in thyroid bed in 11 of 112 patients without previous history of radioiodine therapy, but 9 of them showed bed uptake in I-131 scan. Tc-99m scan showed no bed uptake in all of the 23 patients with previous history of radioiodine therapy, in contrast 14 of them (60.9%) showed bed uptake in I-131 scan. Conclusion: These results suggest that Tc-99m scan has poor detectability for residual thyroid tissue or metastatic lesion in thyroidectomized differentiated thyroid cancer patients, compared to high dose I-131 therapy scan. Tc-99m scan could not detect any remnant tissue or metastatic lesion in patients with previous history of radioiodine treatment, especially.