• Journal of Chest Surgery
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• 제33권6호
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• pp.476-486
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• 2000

Background: Pulmonary atresia with intact ventricular septum(PA/IVS) is an anatomically heterogenous anomaly with a variety of surgical strategies possible. The purpose of the study is to evaluate the influence of right ventricular size on the early and midterm results of surgical repair of PA/IVS. Material and method: Medical records of 20 consecutive patients with PA/IVS operated on between January 1993 and August 1999 were retrospectively reviewed. There were 12 boys and 8 girls whose ages ranged from 2 days to 14.5 months (median 6 days). Their body weight ranged from 2.52kg to 9.35 kg(median 3.18kg). The preoperative Z-value of the diameter of the tricuspid valve(T-valve) was less than or -4 in 5 patients, between -4 and -2 in 1, between -2 and 0 in 7, between 0 and 2 in 6, and greater than or 2 in 1. All patients who had z-value of tricuspid valve greater than -2.05 were attempted biventricular repair(n=15) and all patients who had it smaller than -4.4 underwent systemic-pulmonary shunt operation only(n=3) or bidirectinal cavopulmonary shunt with right ventricular reconstruction(n=2). Result: Two early deaths(2/20, 10%) occurred. Both were infants who underwent transannular patch with shunt. One of these two had huge right ventricle(Z-value of tricuspid valve = 5). There were 2 late non-cardiac deaths 3 and 7 months after operations respectively. Follow-up was completed in all children at a mean of 35.3 months(range, 5 to 54 months). 10 of 11 survivors who underwent transannular patch or valvotomy with or without shunt procedure were in NYHA functional class I even though some of them had small interatrial communication or patent shunt. All three patients who had shunt procedure only at initial palliation completed Fontan procedures with no death. Two patients who underwent right ventricular outflow reconstruction with bidirectional cavopulmonary shunt were also in good condition. Conclusion: The transanular RVOT patch or valvotomy with or without systemic-pumonary shunt as an initial palliative procedure to achieve biventricular repair for the patients who had neither too small nor too large right ventricle(-2.05$\leq$Z-value of T-value of T-valve$\leq$2) could be performed at low operative risk(1/14 7.1%). Systemic-pulmonary shunt procedure and bidirectional cavopulmonary shunt procedure for the patients who had small right ventricle(Z-value of T-valve$\leq$4.4) could be also performed with low risk. But a patient with huge right atrium and ventricle(Z-value of t-valve=5) had poor operative result.

• 한국염색가공학회지
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• 제20권3호
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• pp.1-7
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• 2008

Three kinds of 135D/108F ITY were produced from raw yam 85D/72F + SDY 50D/36F with. interlacing pressure $1.5kg/cm^2$, $2.5kg/cm^2$, $3.5kg/cm^2$ respectively. 72 kinds of sized yams were manufactured from three ITYs by altering sizing speed, sizing temperature and sizing tension. The mechanical characteristics of 72 kinds of plain fabrics which were woven using the sized yam as a warp were analyzed after scouring. The initial modulus of scoured fabric responded sensitively to the sizing speed in high tension. The WT of scoured fabric recorded the. highest1n the conditions of sizing tension 30g, and air pressure $2.5kg/cm^2$ in interlacing treatment. When sizing temperature was high, the WT value appeared low, but when sizing speed was high, the WT value was much affected by air pressure in interlacing raw yam. The MIU value of fabric according to sizing tension variations increased up to sizing tension 40g, but decreased above it. The bulk density decreased up to sizing tension 30-40g, but increased above it. In addition, the bulk density decreased as sizing temperature increased.

• 한국인터넷방송통신학회논문지
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• 제17권6호
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• pp.19-25
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• 2017

본 논문은 비트코인 채굴에 필요한 SHA-256 암호 해시 값(n)을 구성하는 2개의 소수(p,q)를 빠르게 해독하는 소인수분해법을 다룬다. 본 논문에서는 Pollard's Rho 소인수분해 알고리즘의 수행횟수를 월등히 감소시킨 알고리즘을 제안하였다. Rho (${\rho}$) 알고리즘은 $(x_0,y_0)=(2,2)$ 초기치에 대해 $x_i=x^2_{i-1}+1(mod\;n)$과 $y_i=[(y^2_{i-1}+1)^2+1](mod\;n)$을 계산하여 1 < $gcd({\mid}x_i-y_i{\mid},n)$ < n으로 소인수를 구한다. 이 알고리즘은 특정 합성수에 대해서는 소인수 분해에 실패할 수 있다. 제안된 알고리즘은 Pollard Rho 알고리즘에 $(x_0,y_0)=(2^k,2^k)$와 ($2^k,2$), $2{\leq}k{\leq}10$을 적용하였다. 그 결과 모든 합성수에 대해 소인수분해를 할 수 있었으며, Pollard Rho 알고리즘의 수행횟수를 67.94% 감소시켰다.

• 한국지반공학회논문집
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• 제23권8호
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• pp.47-57
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• 2007

본 연구는 사질토로 준설매립된 지반의 액상화 평가를 위해 반드시 요구되는 초기 밀도특성을 분석하였고, 국내 내진 설계기준에서 제시한 SPT-N을 이용한 액상화 간편예측 방법의 문제점을 분석하여 개선방안을 제시하였다. 기존 시공사례를 토대로 매립 직후 준설매립지반의 밀도특성을 분석한 결과, 상대밀도와 초기 N값은 대체로 각각 $40{\sim}50%,\;5{\sim}8$의 범위에 분포하였다. 액상화 간편예측에 있어서 유효상재압 보정의 Liao & whitman식은 항상 지진에 취약한 상부층이 하부층보다 액상화 저항응력이 크게 산정되어 Skempton식의 적용이 추천된다. 또한, 설계단계에서 준설매립 지반의 심도별 N값을 산정할 경우에는, 유효응력에 따른 N값의 변화를 나타내는 누승함수 $N=1.35{\sigma}^{'0.75}$를 이용하여 액상화 간편예측을 실시할 것을 추천한다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권2호
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• pp.124-127
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• 2004

W/n-GaN Schottky diodes were irradiated with $^{60}Co\;{\gamma}-rays$ to doses up to 315Mrad. The barrier height obtained from current-voltage (I-V) measurements showed minimal change from its estimated initial value of ${\sim}0.4eV$ over this dose range, though both forward and reverse I-V characteristics show evidence of defect center introduction at doses as low as 150 Mrad. Post irradiation annealing at $500^{\circ}C$ increased the reverse leakage current, suggesting migration and complexing of defects. The W/GaN interface is stable to high dose of ${\gamma}-rays$, but Au/Ti overlayers employed for reducing contact sheet resistance suffer from adhesion problems at the highest doses.

• 한국세라믹학회지
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• 제24권5호
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• pp.453-460
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• 1987

β'-sialon(Z=2.7) specimens with <30%wt. graphite as a reducing agent were decomposed at 1350°up to 1,450℃ under the atmosphere of 90% N2-10%H2. The decomposition of β'-sialon was calculated from the change in Z-value, and the formation of new minerals was identified from X-ray diffraction patterns. The decomposition reactions of sialon were considered to yield a stable sialon close to β-silicon nitride and some aluminum compounds according to the following equations; β'-sialon(s)＋C(s)＋N2(g)→β2-sialon(metastable)＋β3-sialon(stalbe phase) β2-sialon(s)＋C(s)＋N2(g)→β3-sialon(s)＋AlN(s)＋α-Al2O3(s)＋15R(s)＋SiO(g)＋Al2O(g)＋CO(g) Z-value; β2( 3.5)>β'( 2.7)>β3( 0.5) The decomposition rate of sialon was controlled by two mechanisms ; One was characterized by the interface area of contact, corresponding to an apparent activation energy of 50.5Kcal/mol in the initial stage, and the other by the diffusion, corresponding to that of 104.3Kcal/mol in the final stage of the decomposition.

• 한국자기공명학회논문지
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• 제6권2호
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• pp.132-141
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• 2002

$^1H$ nuclear magnetic resonance (NMR) relaxations have been investigated in ammonium sulfate $((NH_4)_2SO_4)$ power at temperatures ranging form 102 K to 440 K. There is a bottleneck in the spin-lattice relaxation between the nuclear spin system and the hindered rotation of ammonium ions, which is certified by measuring the relaxation according to the initial condition of the spin system. For temperatures below 318 K the $^1H$ spin-lattice relaxations have double-exponential behaviors with the exponent, n, having a value 2>n>1 initially and n=l after a long time. Above 318 K not only is the relaxation exponential initially with exponent n=1, but it is a single-exponential over the entire time, resulting in one $T_1$ value. The two types of $NH_4^+$ ions have different activation energies for hindered rotation, $E_a^1=0.27{\pm}0.02eV$ and $E_a^11=0.12{\pm}0.0eV$, in the ferroelectric phase.

• 대한환경공학회지
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• 제29권7호
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• pp.783-792
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• 2007

부직포 여과막 생물반응조의 질산화 성능을 파악하기 위하여 주입폐수의 암모니아 농도를 $54\sim1,400$ mg/L 그리고 알칼리도를 $43\sim10,480$ mg/L로 변화시키면서 약 11시간의 체류시간에서 641일간 실험을 실시한 결과 반응조의 MLSS농도는 최초의 2,650 mg/L 에서 830 mg/L까지 감소하였다가 최고 8,340 mg/L까지 증가함으로써 반응조의 용적부하는 $0.120\sim3.130$ kg $NH_3-N/m^3-day$의 범위에서 변하였으나 F/M 비는 $0.067\sim0.414$ kg $NH_3-N/kg$ MLSS-day의 적은 변화를 보였다. 각 실험단계별 평균 질산화 효율이 $35.2\sim100%$로서, 최대 질산화율은 2.970 kg $N/m^3-day$ 또는 0.489 g N/g MLVSS-day로 나타났다. MLVSS의 질산화미생물 분율은 최초의 7.1%에서 최고 100%까지 변하였으나 부직포 여과막에 형성된 생물막의 경우에는 2.2%의 매우 낮은 값을 보였다. 미생물 성장계수는 0.117 g VSS/g N removed로 그리고 알칼리도 소모량은 평균 7.08 g alkalinity/g NOx-N produced로 측정되었다. 이러한 실험결과로 보아 부직포 여과막 생물반응조가 고농도 암모니아 폐수의 질산화에 적합한 공법으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.30-31
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• 2021

This study aims to build a deep learning model that can predict the value of concrete mixing properties according to a given concrete strength value. A model was created for a total of 1,291 concrete data, including 8 characteristics related to concrete mixing elements and environment, and the compressive strength of concrete. As the deep learning model, DNN-3L-256N, which showed the best performance on the prior study, was used. The average value for each characteristic of the data set was used as the initial input value. In results, in the case of 'curing temperature', which had a narrow range of values in the existing data set, showed the lowest error rate with less than 1% error based on MAE. The highest error rate with an error of 12 to 14% for fly and bfs.

• 대한치과보철학회지
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• 제43권3호
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• pp.379-392
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• 2005

Statement of problem. One of the common problems of dental implant prosthesis is the loosening of the screw that connects each component, and this problem is more common in single implant-supported prostheses with external connection, and in molars. Purpose. The purposes of this study were: (1) to compare the initial abutment screw detorque values of the six different implant-abutment interface designs, (2) to compare the detorque values of the six different implant-abutment interface designs after cyclic loading, (3) to compare the detorque values of regular and wide diameter implants and (4) to compare the initial detorque values with the detorque values after cyclic loading. Material and methods. Six different implant-abutment connection systems were used. The cement retained abutment and titanium screw of each system were assembled and tightened to 32Ncm with digital torque gauge. After 10 minutes, initial detorque values were measured. The custom titanium crown were cemented temporarily and a cyclic sine curve load(20 to 320N, 14Hz) was applied. The detorque values were measured after cyclic loading of one million times by loading machine. One-way ANOVA test, scheffe’s test and Mann-Whitney U test were used. Results. The results were as follows : 1. The initial detorque values of six different implant-abutment connections were not significantly different(p>0.05). 2. The detorque values after one million dynamic cyclic loading were significantly different (p<0.05). 3. The SS-II regular and wide implant both recorded the higher detorque values than other groups after cyclic loading(p<0.05). 4. Of the wide implants, the initial detorque values of Avana Self Tapping Implant, MIS and Tapered Screw Vent, and the detorque values of MIS implant after cyclic loading were higher than their regular counterparts(p<0.05). 5. After cyclic loading, SS-II regular and wide implants showed higher detorque values than before(p<0.05).