• Korean Journal of Materials Research
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• 제23권12호
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• pp.687-694
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• 2013

This study was performed with an aim to improve the early-age strength of concrete containing fly ash, which is known to increase the long-age strength of concrete, reduce drying shrinkage, and enhance water tightness. The composition was partially substituted with calcium sulfoaluminate (CSA), from which ettringite is actively produced, in the early stages of hydration to verify its effect on improving the early-age strength and to determine the optimal mixing ratio. For this purpose, up to 30 % of the cement weight was substituted with fly ash, and the amount of CSA substitution was 8% of the fly ash weight. The mixtures were then fabricated into concrete specimens for compressive strength measurement and analysis of the correlation between the hydration products and the compressive strength.

• Proceedings of the Korean Information Science Society Conference
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• 한국정보과학회 2000년도 봄 학술발표논문집 Vol.27 No.1 (A)
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• pp.18-20
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• 2000

캐리-세이브 가산기(CSA)는 연산식의 빠른 수행을 위해 가장 일반적으로 쓰이는 연산기중에 하나이다. 일반적인 CSA 적용의 근본적인 한계로는, 연산 회로중에 바로 덧셈 연산으로 변환되는 부분만이 적용이 가능하다는 사실이다. 이러한 제한점을 극복하기 위하여, 우리는 간단하고도, 효율적인 CSA 변환 방법을 제시한다. 이들은(1) 멀티플랙서를 포함한 최적화, (2) 회로 경계를 포함한 최적화, (3) 곱셈기를 포함한 최적화이다. 이러한 방법을 포함하여, 우리는 전체적인 회로에서 CSA를 충분히 사용할수 있는 새로운 지연시간 최적화를 목표로 하는 CSA 변환 방법을 만들어 내었다. 실험에서는 실제적인 여러 회로에 대해 제시된 방법이 효율적임을 보였다.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.369-372
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• 2005

This study is about physical properties of concrete with changing displacement ratio of calcium sulfa aluminates(CSA) type admixture. Firstly, test shows that as displacement ratio of CSA increases and setting properties changes, fluidity and air contents decreases. In water to binder ratio 35$\%$ and 45$\%$, concrete using the cement replacing CSA 4$\%$ by volume shows that bleeding decreases 94.7$\%$ and 74.3$\%$ respectively, compared with plain concrete. In addition, setting time was promoted around 3 to 6 hour and 1 to 4 hour respectively. For harden concrete, increase of displacement ratio caused tendency of higher compressive strength as OPC has at early age. Replacing higher CSA admixture led to reduce of drying shrinkage.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 한국자원리싸이클링학회 2005년도 추계정기총회 및 제26회 학술발표대회 고분자리싸이클링기술 특별심포지엄
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• pp.330-334
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• 2005

본 연구에서는 유해 중금속을 다량 함유하고 있는 산업폐기물의 고화 처리에 사용되는 칼슘설포알루미네이트(4CaO $3Al_2O_3\;SO_4$ 이후부터 CSA로 기입)의 제조를 위해 철강부산물인 압연 슬러지를 활용하여 그 특성에 대해 조사하였다. 본 연구에서는 철강 부산물인 압연슬러지 외에 석회석 미분물, 인산부산 석고를 혼합하여 칼슘알루미네이트 상을 합성하였다. 합성 결과 소성온도 $1250^{\circ}C$에서부터 CSA가 합성되었고, 이와 함께 칼슘실리케이트$(2CaO\;SiO_2)$와 칼슘알루미노페라이트($4CaO\;Al_2O_3\;Fe_2O_3$)도 함께 합성되었다. CSA 합성에 미치는 중금속 영향을 관찰한 결과 원료의 중금속이 CSA 합성 온도를 낮추는 효과가 있는 것으로 나타났다. CSA를 이용한 철강산업 폐기물의 중금속 고용 처리 연구에서도 본 실험에서 합성된 CSA가 폐기물의 중금속 고화 처리에 효과가 있는 것으로 나타났다.

• Korean Journal of Metals and Materials
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• 제46권7호
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• pp.437-442
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• 2008

The synthesis and hydration of Calcium Sulfo Aluminate[$3CaO{\cdot}3Al_2O_3{\cdot}CaSO_4(C_4A_3{\overline{S}})$, CSA cement utilizing secondary steelmaking refining slags is studied for recycling the discarded steel plant wastes to meet the environmental requrations imposed on the steel industry. Raw materials of secondary refining slag, lime sludge, gypsum and bauxite were prepared to be sintered at $1,250^{\circ}C$. The sintered samples were hydrated for 1, 3 and 7 days to evaluate the mineralogical and physico-mechanical properties. The hydration products evaluated with the aid of SEM and XRD analyses confirmed the formation and the continuing growth of ettringite phase with the further hydration times, which plays a role in developing the early strength and the expansion properties of cements. The physico-mechanical properties of hydrated CSA products employing the recycled steelmaking refining slags determined in terms of compressive strength and linear expansion of hydrated products are found to be superior to those of the Ordinary Portland Cement(OPC) or the other commercial CSA cements.

• Journal of the Korean Society of Physical Medicine
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• 제17권1호
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• pp.41-48
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• 2022

PURPOSE: This study examined the relationship between the cervical lordosis angle (CLA) and the craniovertebral angle (CVA) and between CVA and a cross-sectional area (CSA) of the cervical muscles. METHODS: In 17 healthy college students, the CLA was measured using a posterior tangent technique. The CVA was analyzed using photographic images, and the CSA of the cervical muscles, including longus colli, longus capitis, and sternocleidomastoid, was evaluated using computerized tomography. The Pearson's correlation coefficient was used to determine the relationship between these variables and a neck disability index. RESULTS: The CVA correlated with the CLA and with a CSA of longus colli (r = .487, p = .047 and r = .592, p = .012, respectively). The CLA correlated with a CSA of longus colli (r = .578, p = .015). CONCLUSION: This study clarified the relationship between the postural, structural, and muscular changes in the cervical regions. A significant correlation was observed between the CVA and a CSA of the longus colli with the CLA and between the CVA and the CSA of the longus colli. Prescription strengthening exercises for the deep neck flexors for individuals with a forward head posture and reduced cervical lordosis are useful.

• Journal of the Korea Institute of Information Security & Cryptology
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• 제17권1호
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• pp.11-20
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• 2007

A fast Montgomery multiplication occupies important to the design of RSA cryptosystem. Montgomery multiplication consists of two addition, which calculates using CSA or RBA. In terms of CSA, the multiplier is implemented using 4-2 CSA o. 5-2 CSA. In terms of RBA, the multiplier is designed based on redundant binary system. In [1], A new redundant binary adder that performs the addition between two binary signed-digit numbers and apply to Montgomery multiplier was proposed. In this paper, we reconstruct the logic structure of the RBA in [1] for reducing time and space complexity. Especially, the proposed RB multiplier has no coupler like the RBA in [1]. And the proposed RB multiplier is suited to binary exponentiation as modified input and output forms. We simulate to the proposed NRBA using gates provided from SAMSUNG STD130 $0.18{\mu}m$ 1.8V CMOS Standard Cell Library. The result is smaller by 18.5%, 6.3% and faster by 25.24%, 14% than 4-2 CSA, existing RBA, respectively. And Especially, the result is smaller by 44.3% and faster by 2.8% than the RBA in [1].

• Journal of Acupuncture Research
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• 제19권5호
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• pp.209-218
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• 2002

Objective : This study was undertaken to examine whether Carthami Semen aquacupuncture (CSA) exerts protective effect against Hg-induced cell injury in rabbit liver. Methods : The cell injury was evaluated by ALT activity and lipid peroxidation was estimated by measuring malondialdehyde (MDA). Results : Hg caused an increase of ALT activity and lipid peroxidation in a dose-dependent-manner over concentrations of 0.1-1 mM, which were prevented by addition of 0.005% CSA. The protective effect of CSA was dose-dependent in concentration range of 0.001 to 0.01%. The increase of ALT activity and lipid peroxidation induced by 0.5 mM Hg were almost completely decreased by addition of 0.01% CSA. When the liver tissues were exposed to 0.5 mM Hg, GSH content was decreased, which was significantly restored by 0.01% CSA. 0.5 mM Hg caused decrease in the amount of total and nonprotein sulfhydryl groups, and 0.01% CSA prevented Hg-induced reduction of nonprotein sulfhydryl group but not protein sulfhydryl group. Conclusions : These results suggest that CSA exerts protective effect against Hg-induced cell injury by antioxidant action resulting from enhancement of nonprotein sulfhydryl group content including GSH in liver.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제34권9호
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• pp.1273-1279
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• 2010

Pressure tubes at the CANada Deuterium Uranium (CANDU) nuclear power plants are periodically inspected in accordance with the CSA N285.4 code. If flaws that do not satisfy the criteria given in CSA N285.4 are detected, the code permits a fitness-for-service assessment to determine the acceptability of the flawed pressure tubes. In this paper, the Wolsong In-service Evaluation System (WIES) is introduced; this system has been developed for the assessment of the flawed pressure tubes and is based on CSA N285.8. Since the system evaluates the integrity of flawed pressure tubes exactly and promptly during an in-service inspection, it will help in operating the Wolsong nuclear power plants without prolonging the outage period.

• Journal of Biomedical Engineering Research
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• 제20권2호
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• pp.205-212
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• 1999

When we want to observe and record a patient's EEG in an operating room, the operation of electrosurgical unit(ESU) causes undesirable artifacts with high frequency and high voltage. These artifacts make the amplifiers of the conventional EEG system saturated and prevent the system from measuring the EEG signal. This paper describes a high-performance bipolar EEG amplifier for a CSA (compressed spectral array ) system with reduced ESU artifacts. The designed EEG amplifier uses a balanced filter to reduce the ESU artifacts, and isolates the power supply and the signal source of the preamplifier from the ground to cut off the current from the ESU to the amplifier ground. To cancel the common mode noise in high frequency, a high CMRR(common mode rejection ratio) diffferential amplifier is used. Since the developed bipolar EEG amplifier shows high gain, low noise, high CMRR, high input impedance, and low thermal drift, it is possible to observe and record more clean EEG signals in spite of ESU operation. Therefore the amplifier may be applicable to a high-fidelity CSA system.