• Design & Manufacturing
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• 제14권3호
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• pp.17-22
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• 2020

As devices such as smartphones, tablet PC, and wearable devices have been miniaturized, the connectors that go into the devices are also designed to be very small. The connector combines the plug and the receptacle to transfer electricity. As devices are miniaturized, the contact shape is formed by partially thinning the thickness of the raw material of the terminal in order to lower the coupling height of the plug and receptacle. The product used in this study is a receptacle terminal used for 0.4mm pitch board to board connector among fine pitch connectors. When the material thickness is reduced by forging the receptacle terminal, the width change of the pin is checked. To reduce the thickness of the material by forging, pre-notching is applied in the first step, forging in the second step, and notching in the third step. After forming the width dimension of the pin to 0.28 mm in the pre-notching process, in the forging process, the material thickness 0.08 mm and 0.02 mm (25%) were forged and the thickness was changed to 0.06 mm and the width change amount of the pin was measured. The facility produced 10,000 pieces at 400 SPM using a Yamada Dobby (MXM-40L) press, and thirty pins were measured and the average value was shown. After forging by using C5210-H (HP) and NKT322-EH, which are frequently used in connectors, analyze the amount of change in each material. The effect of punching oil on forging is investigated by appling FM-200M, which is highly viscous, and FL-212, fast drying oil. This study aims to minimize mold modification by predicting the amount of material change after forging.

• 한국주조공학회지
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• 제26권3호
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• pp.140-145
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• 2006

Sr, added in the hypereutectic Al-Si alloys, is absorbed on the surfaces of primary Si as well as eutectic Si, and can change the growth mode of primary Si from non-faceted to faceted mode, as the amount of Sr increases larger than 0.04 wt.%, even though it cannot affect the grain size of primary Si, significantly. The EBSD analysis shows that the traction of ${\Sigma}3$ boundary(twin boundary) increases as the amount of Sr in the hypereutectic Al-Si alloys increase until the over-modification occurs at 1.6 wt.%Sr and proves that the change in growth mode of primary Si results from the change of TPRE growth to IIT growth.

• 한국생산제조학회지
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• 제19권2호
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• pp.191-197
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• 2010

In spite of a large amount of previous research, detail study on modified mass in proportional damping system is not well understood. It is common to predict structural dynamic design parameters due to the change of mass, but to predict the amount of modified mass and the location where the mass is being modified are rarely found in previous literature. Such inverse problem required detail analytical study in order to understand structural modification in proportional damping system. This paper predicts the modified mass and the modified mass location in proportional damping system using sensitivity coefficients and iterative method. The sensitivity coefficients are obtained from the change of eigenvectors due to mass modification. This method is applied to a horizontal beam and three degree of freedoms system. To validate the predicted changing mass and its location, the obtained results are compared to the reanalysis result which shows good agreement.

• 유기물자원화
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• 제20권1호
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• pp.23-30
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• 2012

본 연구는 향후 최적 소각용량의 산정에 관해 재평가가 요구되고 있는 실정에서 반입되는 폐기물 발생량, 발열량 증가 및 B시 구역별 유동인구 변화 등을 고려하여 소각 사업소의 최적 가용용량을 예측하고, 예측된 가용용량을 기초로 하여 각 소각 사업소 별 처리량 대안에 대해 연구하는 게 목적이다. B시의 과거 인구추이를 바탕으로 인구변화량을 예측한 결과 전체 인구는 감소추세에 있으나, 일부 지역에 따라서는 아파트 단지 증가 등으로 인구 집중 현상이 나타나 현재와 비슷할 것으로 판단된다. 또한 인구예측을 통한 폐기물 발생량 예측 시 인구의 감소에 의한 폐기물 발생량은 감소할 것으로 판단되지만, 총 폐기물 발생량 중 가연성분 발생량은 증가할 것으로 예측되어 가연성 성분 및 소각 처리량은 D 소각 사업소를 제외하고는 적정할 것으로 예측된다. 따라서 현재 D소각 사업소의 소각율은 72.7%로 전국 소각비율 59.1%보다는 높지만 향후 소각량 확보를 위하여 B시의 MBT시설의 잔재폐기물 및 RDF 회수 잔재물 등과의 혼재 소각과 하수슬러지 및 음식물 쓰레기의 혼재소각이 필요하다고 판단되어지며 2015년 이후 D 소각 사업소를 폐쇄한다고 가정하였을 때는 각 소각장과의 거리와 가용할 수 있는 소각장 규모를 파악하여 경제성에서 가장 적합한 연동구역에 운반(연동제)하여 운영하는 방법이 경제적일 것으로 예측된다. 이에 D 소각 사업소의 경우는 새로운 소각시설 설치에 따른 주민불편 및 사회적 피해를 고려하여 폐수처리장 통합연계 시스템 구축에 따라 폐기물과 혼재 처리할 수 있는 장래의 여유 소각을 할 수 있는 시설 확보 측면에서 2020년까지 운영이 필요하고, H나 M 소각 사업소는 적정 소각량이 감소하는 경우 3개 소각시설이 운휴 기간이 없이 운영되기 위해서 2기를 확보하고 단위사업별 1기 단위로 6개월씩 단위 운영 병행제로 하는 관리방안의 구상도 해결방안이라고 판단되어 진다.

• Geomechanics and Engineering
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• 제5권5호
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• pp.401-417
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• 2013

The results of an experimental program regarding the effects of gradation on shear strength and volume change behavior of silty sands are presented. Consolidated drained direct shear tests were performed on two clean base sands and twelve silty sands obtained by mixing those base sands with two different non-plastic silts at various fines contents (${\leq}$ 25%). Drained shear strengths were observed to be not significantly influenced by either base sand gradation or silt gradation or fines content for the studied range. Increasing fines content has increased the volumetric contraction of specimens at similar void ratio. However, the amount of increase in volumetric contraction of silty sands were found to be affected by silt gradation when other influencing factors such as fines content, base sand gradation and mineralogy were kept the same. Moreover, the amount of increase in volumetric contraction of silty sands were also found to be affected by base sand gradation when other influencing factors such as fines content, silt gradation and mineralogy were kept the same.

• 기술사
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• 제43권6호
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• pp.39-45
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• 2010

Soil plays a huge role in climate change, because even a tiny loss of 0.1% of carbon emitted into the atmosphere from European soils is the equivalent to the carbon emission of 100million extra cars on Europe's roads - an increase of about half of the existing car fleet. Soils contain around twice the amount of carbon in the atmosphere and three times the amount to be found in vegetation. Europe's soils are an enormous carbon reservoir, containing around 75billion tonnes, and poor management can have serious consequences. Soil degradation is accelerating across the EU, with negative effects on human health, ecosystems and climate change - and on economic prosperity and quality of life. Climate change is identified as a common element in many soil threats. Europe's soils urgently need better protection. The current trend of soil degradation needs to be reversed, and soil management practices must be improved if a high rate of soil carbon sequestration is to be achieved.

• PNF and Movement
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• 제19권3호
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• pp.351-359
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• 2021

Purpose: This purpose of this study was to investigate the effects of initial cognitive status on the recovery of functional status in patients with subacute stroke. Methods: The participants were 111 patients with subacute stroke, divided into two groups: mini-mental state examination (MMSE) <20 (n=49) group and MMSE ≥20 (n=62) group. Clinical evaluation scores were collected before and after rehabilitation. The repeated measurements ANOVA was used to confirm the changes in functional status before and after intervention in the two groups. Changes in functional status within the group were examined through a paired test. A Pearson correlation coefficient analysis was performed to identify the correlation between MMSE change amount and functional status score. Results: In each of the two groups, according to the initial cognitive status, the clinical evaluation score increased statistically significantly, but there was no difference between the two groups in the degree of significant increase. When examining the correlation between the MMSE change amount, according to the initial cognitive state and the functional state score change amount, it was found, only in the group with MMSE <20, that the larger the change in the MMSE score, the greater the functional state change of Berg balance scale, Rivermead Mobility Index, and motor assessment scale. This did not apply to the group with MMSE ≥20. Conclusion: Initial cognitive status should be considered when setting the patient's goal, and considering cognitive improvement when constructing a rehabilitation program is thought to have a positive effect on rehabilitation services.

• 한국기후변화학회지
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• 제34권12호
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• pp.5081-5092
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• 2021

Paleoproxy records indicate that abrupt changes in thermohaline circulation (THC) were induced by rapid meltwater discharge from retreating ice sheets. Such abrupt changes in the THC have been understood as a hysteresis behavior of a nonlinear system. Previous studies, however, primarily focused on a near-static hysteresis under fixed or slowly varying freshwater forcing (FWF), reflecting the equilibrated response of the THC. This study aims to improve the current understanding of transient THC responses under rapidly varying forcing and their dependency on forcing time scales. The results simulated by an Earth system model suggest that the bifurcation is delayed as the forcing time scale is shorter, causing the Atlantic meridional overturning circulation collapse and recovery to occur at higher and lower FWF values, respectively. The delayed shutdown/recovery occurs because bifurcation is determined not by the FWF value at the time but by the total amount of freshwater remaining over the THC convection region. The remaining freshwater amount is primarily determined by the forcing accumulation (i.e., time-integrated FWF), which is modulated by the freshwater/salt advection by ocean circulations and freshwater flux by the atmospheric hydrological cycle. In general, the latter is overwhelmed by the former. When the forced freshwater amount is the same, the modulation effect is stronger under slowly varying forcing because more time is provided for the feedback processes.

• Architectural research
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• 제8권1호
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• pp.69-76
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• 2006

The purpose of this study is to suggest policies to improve the price escalation system in a construction contract through a Policy Delphi technique. The Delphi, including two times questionnaires and a group discussion, was conducted by joining 14 experts. Also, the escalation provisions of various countries were examined. Results of the Delphi showed that the minimum fluctuation rate for price escalation was desirable at a level of 3%. To compute the fluctuation rate, calculating the price fluctuation of overall articles was more desirable than using price indices. A bidding date was more reasonable as the initial date of change in price. Losses caused by price change should be shared between contractor and owner; therefore a deduction rate should be introduced in price escalation. Meanwhile, overhead and profit should be adjusted in proportion to the fluctuation rate; but advance payment or the delayed construction amount should be deducted from the adjusted amount.

• 한국조리학회지
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• 제3권
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• pp.239-257
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• 1997

This study investigated the effect of the addition of alcohol on the quality change of Chungkukjang during the aging, The Cung-kuk-jang was made by the degree of 3, 5, 10%, respectively, and determined NH2-N, NH3-N, total acidity, cell numbers, lactate, succinate and phenolic acid to measure the change of flavor component in the aging of 2$0^{\circ}C$. 1. In the treatment groups of different amount of alcohol and salt added and aging period of Chung-kuk-hang, NH2-N was more decreased with more addition of alcohol and salt in the 3-and 10-day of aging. NH3-N was increased gradually in the addition of up to 2.0% alcohol and then decreased in the 3-and 10-day of aging. 2. In the treatment groups of different amount of alcohol added and aging period Chung-kuk-hang, the total acidity was more decreased with more addition of alcohol and higher degree of salt. Cell number was decreased rapidly with the addition of 1.0% alcohol in the 3-day and then decreased relatively and in the 10-day of aging, and it was increased with the addition of alcohol 3. With the addition of alcohol and the different growing temperature, the content of phenolic acid was more browning changed at 3$0^{\circ}C$ than that of at 2$0^{\circ}C$ and the phenol content of each group was decreased with increasing the addition amount of alcohol. Thus, the more addition of alcohol amount would the more extend the period of Chung-kuk-hang aging.