In this study, the effect of compressive loading of carbon nanotube (CNT) mixed cement composites was investigated. To evaluate the electrical resistivity variation of 30%∼60% of compressive load of cement composites containing 1.0% CNT, 1.0% CNT was added to cement composites and compressive strength was calculated. The greater the change in electrical resistance to compressive load, the more vulnerable to internal conductive networks. Also, as the amount of CNT mixed increases, the electrical resistance to the load is more sensitive and it is expected to be mixed more than 1.0%.

흉부 CT스캔에서 공기, 지방, 근육, Background의 HU, 잡음 그리고 신호 대 잡음비의 변화를 측정해 영상 화질에 미치는 지멘스 ADMIRE(Advanced Modeled Iterative Reconstruction)의 영향을 조사했다. 실험 결과에 따르면 ADMIRE Strength가 커질수록 잡음은 감소하고 신호는 증가하여, 결론적으로 신호 대 잡음비는 증가하는 것으로 나타났다. ADMIRE는 기존 영상 재구성 알고리즘인 FBP와 비교하여 잡음을 28~61%까 지 줄일 수 있으며, 신호 대 잡음비는 16~100%까지 향상시킨다.

본 연구의 목적은 실제 한국어 교실에서 교사의 교감적 언어사용-반복전략이 나타나는 양상을 보여주는데 목적이 있다. 이 연구는 교사가 학습자의 말을 다시 말하는 반복전략이 대화 유지를 도우고 유대감 형성에 영향을 주는 교감적 언어사용으로 작용한다고 본다. 따라서 본고는 교사의 교감적 언어사용-반복전략의 개념을 체면이론을 바탕으로 적극적, 소극적 전략으로 나누어 설정하였다. 이를 다시 동의, 경청으로 나누어 분류해 실제 한국어 교실에서 나타나는 교사의 반복 발화 양상을 분석해 보았다.

지지력이 큰 하부지반에 구조물의 하중을 전달하기 위한 방안으로 말뚝기초가 대부분 적용되고 있다. 이 연구에서는 접합부에 보강되는 철근량에 따라 반복하중 하에서 프리캐스트공법과 철근 및 속채움 콘크리트로 말뚝머리부를 보강한 철근콘크리트 말뚝(HPC)과 기초접합부 거동을 실험을 통해 평가하였다. 철근량에 변화에 따라 제작된 두 종류의 접합부 실험체의 균열패턴과 파괴거동은 유사한 수준으로 평가되었다. 철근량 1.77배 증가에 기인하여 BS-H25 실험체는 BS-H19 실험체에 비해 최고하중은 약 1.47배 증가하였지만 연성비는 정가력시 76%, 부가력시 70% 수준을 나타내었다. 강성감소는 접합부 철근 항복 이후 BS-H19 실험체와 BS-H25 실험체는 정가력시 초기강성의 약 66% ~ 71% 수준으로 부가력시 54% ~ 57% 수준으로 감소되었고 BS-H25 실험체가 평균 13% 높은 강성값을 나타내었다. 극한하중 상태에서의 BS-H19와 BS-H25 실험체의 누적 에너지 소산량은 사용하중 상태에 비해 약 5.5배 및 6.6배 큰 값으로 측정되었다.

실시간 그래픽스 응용에서 연체의 움직임을 효율적으로 생성하기 위해 다양한 방법이 제안되었다. 연 체 구성 요소들의 위상을 유지하기 위해서는 서로를 묶는 힘이 존재할 수밖에 없으며, 이는 강직도 (stiffness)로서 수치적분의 시간간격의 크기를 제한하고 효율성을 떨어트린다. 이를 해결하기 위해 시간간 격을 늘릴 수 있는 암시적 적분이 제안되었지만, 대규모 행렬이 포함된 선형시스템을 풀어야 해서 계산복 잡도가 크게 높아진다. 이 문제를 개선한 근사 기법들은 댐핑 효과의 증가와 정확성의 손실을 초래할 수 밖에 없다. 본 논문에서는 선형시스템을 풀지 않고도 안정성은 크게 높이기 위해 조화진동에 근거하여 스 프링 힘을 적분하고, 이를 근사 암시적 기법과 결합하여 안정성을 극대화 하는 방법을 제안한다. 이 기법 은 GPU를 통한 병렬화가 용이하여 거대한 규모를 가진 연체 객체의 움직임을 실시간에 생성할 수 있다.

In this study, it evaluate the impact resistance of UHPC by repeated impact. smooth steel fiber and polyvinyl alcohol fiber were reinforced in UHPC respectively. Overall, the impact resistance of the specimens reinforced with 0.4vol.% PVA fiber was high, and the crater diameter was small in specimens using 13mm fiber.

본 연구에서는 반복학습과 반복인출연습이 학습 파지에 미치는 효과를 비교해 보기 위하여 중학교 3학년 52명을 피험자로 하여 산문자료 학습 후 단답형과 선택형 문제형식으로 2018년 3월 20일 1차 검사, 1주 지연 후에 2차로 장기 파지를 검사하였다. 그 결과, 단답형에서는 반복인출연습이 반복학습에 비해 더 높은 수행을 보였고, 선택형에서는 반복학습과 반복인출연습의 효과가 비슷하게 나타났다. 그리고 학습조건과 문제유형은 단기 파지에서만 유의미하게 상호작용효과가 있는 것으로 나타났다. 이를 통해 상대적으로 인출을 위한 많은 노력이 요구되는 재생(recall)에서는 단순히 학습 내용을 반복학습하는 것보다는 반복인출해 보는 것이 더욱 효과적인 것으로 판단된다. 이것은 Bjork의 ‘바람직한 어려움(desirable difficulty)’과도 일치하며, 학습 파지에서 인출연습의 효과를 강력히 지지하는 것으로 볼 수 있다. 그러므로 실제 교실 수업에서도 형성평가나 퀴즈 등의 형태로 인출연습을 해 보는 것이 학습 파지에 효과적이라는 것을 제안한다.

Background: Cassia tora L., an annual or perennial plant of the Fabaceae family, is traditional medicine with various biological activities, including anti-constipation and, anti-inflammation. Chemical compounds such as anthraquinone glycoside and naphthalene derivatives have been isolated from this plant. Cassia tora L. is a common contaminant of agricultural commodities, but is toxic to cattle and poultry. Methods and Results: To investigate the potential toxicity, Cassia tora L. aqueous extract (CO) was administered orally to rats for 26 weeks at 0 (control), 300, 1,500 and 3,000㎎/㎏/day (n = 10 for male rats for each dose). The positive control comprised animals orally administered anthraquinone 100㎎/㎏/day. There was no treatment-related mortality. An increase in the kidney weight was observed at 3,000㎎/㎏/day of CO and anthraquinone 100㎎/㎏/day. Macrophage infiltration in the colon was observed at CO 1,500 and 3,000㎎/㎏/day and anthraquinone 100㎎/㎏/day, but there were no significant toxicological changes in the incidence and severity of the finding. Conclusions: The oral no-observed-adverse-effect level (NOAEL) of CO was 3,000㎎/㎏/day in male rats and no target organs were identified. In addition, 300㎎/㎏ was found to be the no-observed-effect level (NOEL) for systemic toxicity under the conditions of the study.

Background: Gastrodia elata Blume is a saprophytic perennial plant in the Orchidaceae family, because of its agricultural and medicinal effectiveness, researchers focus on its genome and chemical components. However, cytogenetic information based on the chromosome structure and composition to construct chromosomal backbone for genome sequencing research and for the development and breeding of plants is very limited. Methods and Results: We determined the metaphase chromosome composition of the G. elata genome by fluorescence in situ hybridization (FISH) using 5S and 45S rDNAs and telomeric repeat probes. The nuclear genome of G. elata was organized into 2 n = 36, with relatively small (2.71 - 5.50㎛)chromosomes that showed gradual decrease in size. Conglutination phenomenon was observed among the metaphase chromosomes, and it was distinguished from that in other plant metaphase chromosome spreads. One pair of signal was detected for each 5S and 45S rDNA in the pericentromeric region and interstitial region on the short arm of chromosomes 10 and 4, respectively, and telomeric DNA signals were detected in the terminal region of most chromosomes. Conclusions: To our knowledge, this is the first FISH chromosome composition result in G. elata and could be useful in more comprehensive molecular cytogenetic and genomic analyses as well as breeding programs of the medicinal plant G. elata.

The goals of this study were to investigate image quality of coronary CT angiography (CCTA) and change of radiation dose by using Adaptive Statistical Iterative Reconstruction (ASIR) technique. 40 subjects with BMI≥25 (A, C groups), 40 subjects with BMI<25 (B, D groups), Groups without ASIR (A, B groups), and with ASIR (C, D groups) were included. There were no statistical differences in image qualities (p>0.05). Radiation doses with application of ASIR were significantly lower than those of ASIR (51-53%, p<0.05). In CCTA scan-nings, ASIR technique helps to reduce radiation dose with preserved image quality.

This paper presents the seismic performance of the steel damper under reversed cyclic loading. The U-shaped steel damper used in this study was designed to have energy dissipation zone with an external diameter of 120 mm, a width of 15 mm, and a thickness of 15 mm. The cyclic loading test was carried out using an uniaxial universal testing machine with a capacity of 2,000 kN. The test results indicated that no strength deterioration of the specimen was found as well as the equivalent damping ratio of the specimen was excellent.

There are reports that inhaling hypertonic saline with bronchodilator is helpful in the treatment of bronchiolitis. However, further studies are needed to determine if it is helpful to inhale hypertonic saline with bronchodilator in children with recurrent wheezing. We aimed to investigate the effect of hypertonic saline inhalation in children with recurrent wheezing. A total of 40 patients under 6 years of age admitted to Kwangju Christian Hospital from December 2014 to May 2016 were enrolled. Patients were randomly assigned to receive salbutamol. In the control group (n=21), salbutamol (2.5-5 mg / 0.5-1 mL) was inhaled four times a day with physiological saline (0.9% normal saline 1-3 mL). In the experimental group (n=19), the same amount of hypertonic saline (5% saline 1-3 mL) was inhaled four times a day instead of physiological saline. We compared the duration of wheezing remission between patients who had recurrent wheezing (n=40). There was no difference in the duration of wheezing remission in patients who had recurrent wheezing. But the hypertonic saline inhalation group had a lower post treatment clinical score on the 2nd-3rd day of admission than the physiological saline inhalation group. In this study, hypertonic saline inhalation therapy was not significantly effective in the treatment of recurrent wheezing. More additional research is needed to determine whether inhaled hypertonic saline is effective in the treatment of recurrent wheezing.

Reversible cerebral vasoconstriction syndrome (RCVS) is a clinic-radiologic syndrome characterized by severe headache and reversible multifocal arterial constrictions that resolve within 3 months. RCVS can be either spontaneous or related to a trigger, such as vasoactive drugs. The authors present the case of a 53-year-old woman who presented with recurrent thunderclap headache. Initial computed tomography angiography demonstrated segmental vasoconstriction of bilateral anterior cerebral arteries. Fourteen days after, initial vasoconstriction was improved as determined by follow up CT angiography. Our patient had recurrent thunderclap headache for a considerable time (around 24 months). However, although she visited many hospitals, the headache was not controlled by any treatment. Fortunately, she did not have any neurological complication and her symptoms relieved after nimodipine treatment. Clinicians should be aware of possible RCVS when a patient has recurrent thunderclap headache for a protracted period.

Seismic performance capacity of CFT seismic retrofit method was studied through cyclic loading test. The added CFT columns share the lateral seismic force of the building with the existing RC columns to prevent building collapse. The experiment shows stable hysteric load-displacement curve.

Seismic performance capacity of CFT seismic retrofit method was studied through cyclic loading test. The added CFT columns share the lateral seismic force of the building with the existing RC columns to prevent building collapse. The experiment shows stable hysteric load-displacement curve.

Traditional marine structures are difficult to construct under the marine environment. These structure have maintenance costs associated with the chloride attack environments. In this paper, a new structure system is proposed to overcome these disadvantages. The connection of precast reinforced concrete girders and bent cap is the main feature of the proposed structure system. To assess the joint performance of the proposed methods, full-scale joint was fabricated and tested under cyclic loading. The key parameters examined were the pile displacement; the strain in the reinforcement; and the crack patterns in the concrete. The test structure behaved stably for cyclic loading. The test structure is analyzed to be safe in all members.

This study examined the ductile behavior of hybrid steel-reinforced concrete beam systems under reversed cyclic lateral loads. All specimens showed a high ductile performance with the displacement ductility ratio of more than 4.6, regardless of the details of dowel reinforcement at the joint region of the developed hybrid beam system.

Cyclic loading tests for a total of nine test specimens were performed to evaluate the seismic performance of the exposed steel column-base plate connections. From the tests, flexural strength, deformation capacity, energy dissipation, and initial stiffness were investigated. The primary test parameters were the thickness of base-plate, embedment length of anchor bolt, the presence of hook, and rib plates. Test results showed that flexural behavior of column base-plate connection was substantially affected by the base-plate thickness, embedment length and the number of anchor bolts. On the other hand, the effect of rib plates on the increase of the flexural performance was not observed. The initial stiffness of the test specimens was about 15% of the flexural stiffness obtained by assuming that the support is fixed. As a result, even if the exposed column base-plate is designed in accordance with current design recommendations, in case that bond strength between concrete and the anchor bolts is not sufficient, the base-plate connection showed an unaccceptable load-displacement behavior.

Seismic performance capacity of CFT seismic retrofit method was studied through cyclic loading test. The added CFT columns share the lateral seismic force of the building with the existing RC columns to prevent building collapse. The experiment shows stable hysteric load-displacement curve.

Seismic performance capacity of CFT seismic retrofit method was studied through cyclic loading test. The added CFT columns share the lateral seismic force of the building with the existing RC columns to prevent building collapse. The experiment shows stable hysteric load-displacement curve