• Steel and Composite Structures
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• 제19권5호
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• pp.1299-1319
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• 2015

This paper presents a detailed parametric study, conducted using finite element tools to cover a range of several geometric and material parameters, on the behaviour of thin-walled partially encased composite (PEC) columns. The PEC columns studied herein are composed of thin-walled built-up H-shaped steel sections with concrete infill cast between the flanges. Transverse links are provided between the opposing flanges to improve resistance to local buckling. The parametric study is confined to eccentrically-loaded columns subjected to major axis bending only. The parameters that were varied include the overall column slenderness ratio (L/d), load eccentricity ratio (e/d), link spacing-to-depth ratio (s/d), flange plate slenderness ratio (b/t) and concrete compressive strength ($f_{cu}$). The overall column slenderness ratio was chosen to be the primary variable with values of 5, 10 and 15. Other parameters were varied within each case of L/d ratio. The effects of the selected parameters on the behaviour of PEC columns were studied with respect to the failure mode, peak axial load, axial load versus average axial strain response, axial load versus lateral displacement response, moment versus lateral displacement behaviour and the axial load-moment interaction diagram. The results of the parametric study are presented in the paper and the influences of each of the parameters investigated are discussed.

• 한국의류학회지
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• 제44권1호
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• pp.53-67
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• 2020

The purpose of this study is to analyze the foot shape and size specification of male high school students. 3D modeling programs such as 'Artec Studio', 'CATIA', and 'Auto CAD' measured the 3D scan data of 361 male high school students provided by KATS. Through principal factor analysis, 10 factors were extracted, including foot length, medial-lateral ratio, and foot length ratio. As the result of the cluster and ANOVA with post-hoc test (Duncan method), the differences among types were clarified. Type 1 (24.7%) represented outward medial-lateral ratio (M-L ratio) with the lowest instep, ankle and little deformed first toe. Type 2 (41.8%) was characterized by the shortest, even M-L ratio, thin ankle and heel, the highest instep and ankle. Type 3 (33.5%) showed the longest, inward M-L ratio, thick ankle and heel, and deformed first toe. As the cross-tabulation of foot length and ball circumference, 17.2 percent was not covered by KS standard; in addition, the foot length was longer than the KS standard. The correlation analysis of key dimensions showed that foot length and ball circumference were highly correlated with other items; therefore, regression equations were derived to estimate other foot measurements using these two items as independent variables.

• 약학회지
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• 제42권1호
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• pp.101-107
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• 1998

The antiparkinsonian agent l-deprenyl, a selective monoamine oxidase (MAO)-B inhibitor, is metabolized in part to l-methamphetamine and l-amphetamine. l< /I>-Deprenyl was evaluated for amphetamine and methamphetamine-like discriminative stimulus effects in rats and its mechanism of action was investigated. Rats were trained under a 5-response, fixed ratio schedule of stimulus-shock termination or a 10-response. Fixed-ratio schedule of food-presentation which discriminate between d-amphetamine (1mg/kg, i.p.) and saline or d-methamphetamine (1mg/kg, i.p.) and saline in a two-lever, operant conditioning procedure. Full generalization was obtained to d-amphetamine (1~3mg/kg). d-methamphetamine (1~3mg/kg) and l-deprenyl (17~30mg/kg) under both the food presentation and stimulus shock termination schedule. l-Deprenyl has dose-dependent amphetamine-and methamphetamine-like discriminative stimulus properties in rats only at doses of 17 and 30mg/kg. Reversible MAO-B inhibitor, RO 16-6491 didn`t show any amphetamine-like discriminative properties. Aromatic amino acid decarboxylase inhibitor, NSD 1015 decreased % responding of l-deprenyl in the methamphetamine-trained rats under the stimulus-shock termination schedule. SKF-525A produced partial inhibition of methamphetamine-like discriminative effects of l-deprenyl under the food presentation schedule. These results suggest that l-deprenyl has no abuse liability at the therapeutic range but there needs some caution at high doses and furthermore, drug discrimination studies under the food presentation and shock termination schedule are useful for the assessment of abuse liability of psychostimulants.

• Earthquakes and Structures
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• 제24권6호
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• pp.455-475
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• 2023

The present study investigates the non-linear soil-pile interaction using three-dimensional (3D) non-linear finite element models. The numerical models were validated by using the results of extensive pile load and shaking table tests. The pile performance in liquefiable and non-liquefiable soil has been studied by analyzing the liquefaction ratio, pile lateral displacement (LD), pile bending moment (BM), and frictional resistance (FR) results. The pile models have been developed for the different ground conditions. The study reveals that the results obtained during the pile load test and shaking cycles have good agreement with the predicted pile and soil response. The soil density, peak ground acceleration (PGA), slenderness ratio (L/D), and soil condition (i.e., dry and saturated) are considered during modeling. Four ground motions are used for the non-linear time history analyses. Consequently, design charts are proposed depended on the analysis results to be used for design practice. Eleven models have been used to validate the capability of these charts to capture the soil-pile response under different seismic intensities. The results of the present study demonstrate that L/D ratio slightly affects the lateral displacement when compared with other parameters. Also, it has been observed that the increasing in PGA and decreasing L/D decreases the excess pore water pressure ratio; i.e., increasing PGA from 0.1 g to 0.82 g of loose sand model, decrease the liquefaction ratio by about 50%, and increasing L/D from 15 to 75 of the similar models (under Kobe earthquake), increase this ratio by about 30%. This study reveals that the lateral displacement increases nonlinearly under both dry and saturated conditions as the PGA increases. Similarly, it is observed that the BM increases under both dry and saturated states as the L/D ratio increases. Regarding the acceleration histories, the pile BM was reduced by reducing the acceleration intensity. Hence, the pile BM decreased to about 31% when the applied ground motion switched from Kobe (PGA=0.82 g) to Ali Algharbi (PGA=0.10 g). This study reveals that the soil conditions affect the relationship pattern between the FR and the PGA. Also, this research could be helpful in understanding the threat of earthquakes in different ground characteristics.

• Journal of Plant Biotechnology
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• 제33권2호
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• pp.105-110
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• 2006

배지 내 식물생장조절물질, 무기물 농도, 질소원 비율이 G. sylvestre 세포배양에 미치는 영향을 알아보고자 실험을 수행하였다 1.0 mg L$^{-1}$ 이상2,4-D 처리시 세포 생장량이 급격히 감소한 반면, 0.5 mg L$^{-1}$ 이하 kinetin 처리구들은 세포 생장량이 큰 차이가 없었다. 따라서 G. sylvestre 세포배양의 경우 2,4-D 1.0 mg L$^{-1}$와 kinetin 0.1 mg L$^{-1}$를 함께 사용하는 것이 세포 생장량 증대에 효율적이라고 판단되었다. 무기물 농도가 G. sylvestre 세포 생장량에 미치는 영향을 조사한 결과 1x MS에서 세포 생장량이 가장 높았으며, 배지 내 무기물 농도가 1x MS 이상일 경우 배지의 낮은 수분포텐셜로 인해 세포생장이 크게 억제되었다. $NH_4^+:NO_3^-$ 비율이 0:60에서 가장높은 생장량을 나타내었으나 세포의 크기가 작고 백색을 나타내었으며 연속배양시 생장량이 점차 감소하므로, G. sylvestre 세포를 연속 배양할 경우 $NH_4^+:NO_3^-$를 20:40으로 사용하는 것이 효과적이라고 생각되었다.

• 설비공학논문집
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• 제1권4호
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• pp.305-312
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• 1989

Laminal natural convection heat transfer in the annulus between isothermal horizontal non-circular cylinders is studied by solving the Navier-Stokes and energy equation using an elliptic numerical procedure. Results are obtained to determine the effects of the diameter ratio($D_o/D_i$) and Rayleigh number on heat transfer. The diameter ratio is varied from 1.5 to 13.0 at Pr=0.7, H/L=1.5 and $10^3{\leqslant}Ra_L{\leqslant}4{\times}10^4$. It is found that the diameter ratio causes a more significant on the local heat transfer coefficient of lower semi-circular cylinder and plate than upper semi-circular cylinder. The mean Nusselt number increases as the diameter ratio and Rayleigh number increase, and is higher than that of the circular annulus with a same wetted perimeter.

• Asian-Australasian Journal of Animal Sciences
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• 제20권4호
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• pp.550-555
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• 2007

The aim of this study was to determine the effect of two lighting programs (continuous lighting (CL) 24L:0D and intermittent lighting (IL) 1L:3D) on the broiler performance, carcass traits, incidence of tibial dyschondroplasia (TD), relative asymmetry (RA), duration of induced tonic immobility (TI), heterophils-lymphocytes ratio (H/L), serum glucose, cholesterol and triglyceride levels. The chicks were randomly divided into 2 treatment groups consisting of 100 chicks per treatment, continuous lighting (CL) 24L:0D or intermittent lighting (IL) 1L:3D. Each treatment consists of 5 replicates of 20 chicks. The experimental period was 6 weeks. Use of IL decreased feed to gain ratio, improved immune response and reduced fearful. Body weight, carcass traits, TD and stress parameters (organ weights, RA, H/L, glucose, cholesterol and triglyceride levels) were not significant in different lighting groups. As a result IL was beneficial for producers and chickens than CL.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권6호
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• pp.2649-2669
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• 2020

In this paper, we analyze the secrecy performance of single-input multiple-output (SIMO) relay systems over κ-μ shadowed fading channels. Based on considering relay model employing decode-and-forward (DF) protocol, two security evaluation metrics, namely, secure outage probability (SOP) and probability of strictly positive secrecy capacity (SPSC) are studied, for which closed-form analytical expressions are derived. In addition, Monte Carlo results prove the validity of the theoretical derivation. The simulation results confirm that the factors that enhance the security include large ratio of (μ_D, μ_E), (m_D, m_E), (L_D, L_E) and small ratio of (k_D, k_E) under the high signal-to-noise ratio regime.

• 한국가금학회지
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• 제49권3호
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• pp.139-144
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• 2022

본 연구는 육계 병아리 시기에 세 가지의 점등시간이 성장 능력, 혈액 생화학 성상 및 스트레스 지표에 미치는 영향을 조사하기 위해 수행되었다. 공시동물은 1일령 Ross 308 육계(57.0±0.12 g) 수컷 252수를 7일 동안 사육하였으며, 처리구는 점등3처리구(24 L, 22 L/2D, 18 L/6D)로 나누고, 처리당 4반복, 반복당 22수를 완전임의 배치하였다. 광원은 LED 전구를 사용하였으며, 기본 조도는 30 lx를 제공하였다. 시험사료는 옥수수-대두박 위주의 시판 사료(ME 3,150 kcal/kg, CP 22.0%)를 이용하였으며, 사료와 물은 자유롭게 섭취하도록 하였다. 점등시간에 따른 체중, 증체량, 사료요구율 및 간 무게 비율은 18 L/6D과24 L 처리구에서 유의적인 차이를 보였으나(P<0.05), 22 L/2D 처리구는 24 L 처리구 및 18 L/6D 처리구간 유의차를 보이지 않았다. 가슴근육의 무게 비율은 18 L/6D 처리구에서 5.59%로 다른 처리구에 비해 낮게 나타났다(P<0.05). 혈청 생화학 성분 중 TG는 점등시간이 줄어들수록 유의적으로 증가하였으나(P<0.05), ALT는 24 L 처리구에 비해 22 L/2D 처리구에서 유의적으로 높았다(P<0.05). 혈청 내 cytokine(IL-6, TNF-α) 함량은 처리구 사이에서 유의적인 차이를 보이지 않았으나, corticosterone 함량은 24 L 처리구가 18 L/6D 처리구에 비해 유의적으로 높은 값을 나타내었다(P<0.05). 결론적으로, 육계 병아리 시기에는 성장 능력과 동물복지를 모두 고려하였을 때 22시간 점등이 적당하다고 사료된다.

• Steel and Composite Structures
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• 제45권5호
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• pp.749-766
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• 2022

This paper investigates the seismic performance of exposed RCFST column-base joints, in which the high-strength steel bars (USD 685) are set through the column and reinforced concrete foundation without any base plate and anchor bolts. Three specimens with different axial force ratios (n = 0, 0.25, and 0.5) were tested under cyclic loadings. Finite element analysis (FEA) models were validated in the basic indexes and failure mode. The hysteresis behavior of the exposed RCFST column-base joints was studied by the parametrical analysis including six parameters: width of column (D), width-thickness ratio (D/t), axial force ratio (n), shear-span ratio (L/D), steel tube strength (f_y) and concrete strength (f_c). The bending moment of the exposed RCFST column-base joint increased with D, f_y and f_c. But the D/t and L/D play a little effect on the bending capacity of the new column-base joint. Finally, the calculation formula is proposed to assess the bending moment capacities, and the accuracy and stability of the formula are verified.