• Coupled systems mechanics
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• 제5권4호
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• pp.285-304
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• 2016

The effects of large rotations and p-delta on the dynamic response of a structure subjected to seismic loading and local uplift of its foundation were analyzed in this work. The structure was modeled by an equivalent flexible mat mounted on a rigid foundation that is supported either by a Winkler soil type or a rigid soil. The equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-mat system where the structure was idealized as a single-degree-of-freedom. The obtained nonlinear coupled system of ordinary differential equations was integrated by using an adequate numerical scheme. A parametric study was performed then in order to evaluate the maximum response of the system as function of the intensity of the earthquake, the slenderness of the structure, the ratio of the mass of the foundation to the mass of the structure. Three cases were considered: (i) local uplift of foundation under large rotation with the p-delta effect, (ii) local uplift of foundation under large rotation without including the p-delta effect, (iii) local uplift of foundation under small rotation. It was found that, in the considered ranges of parameters and for moderate earthquakes, assuming small rotation of foundation under seismic loading can yield more adverse structural response, while the p-delta effect has almost no effect.

• Steel and Composite Structures
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• 제14권1호
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• pp.1-20
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• 2013

This paper presents the formulation for a novel force-based 1-D compound-element that captures both material and second order P-${\Delta}$ nonlinearities in steel frames. At the nodal points, the element is attached to nonlinear rotational and a translational springs which represent the flexural and axial stiffness of the connections respectively. By decomposing the total strain in the material as well as the generalised displacements of the flexible connections to their elastic and inelastic components, a secant solution strategy based on a direct iterative scheme is introduced and the corresponding solution strategy is outlined. The strain and slope of the deformed element are assumed to be small; however the equilibrium equations are satisfied for the deformed element taking account of P-${\Delta}$ effects. The formulation accuracy and efficiency is verified by some numerical examples on the nonlinear static, cyclic and dynamic analysis of steel frames.

• 한국가축번식학회지
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• 제15권1호
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• pp.7-13
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• 1991

본 實驗은 精子 洗滌液의 pH와 洗滌頻度 및 수소개체가 精子洗滌液內 水素이온과 精子尖帽反應에 미치는 影響을 究明하기 위하여 실시하였는바 그 결과는 다음과 같다. 1. 精子를 SHP液으로 4차례 反復洗滌하여 培養하였을 때, 洗滌液의 吸光度差間 變化는 2차 精子洗滌液에서 가장 높았다. 2. 精子를 pH 5.99, 6.38, 6.78, 7.10, 7.40, 7.69, 8.15, 8.45 및 8.83 SHP液으로 3번 洗滌하였을 때, 精子洗滌液의 吸光度差間 變化는 pH 7.69~8.83에서 유의하게 증가하였으며, 1차 精子洗滌液이 2차와 3차 精子洗滌液보다 유의하게 높았다. 3. Holstein, KNC 및 Hereford 精子를 pH 5.99, 6.38, 6.78, 7.10, 7.40, 7.69, 8.15, 8.45 및 8.83의 SHP液으로 3번 洗滌하였을 때, 精子洗滌液의 光度差間 變化는 Holstein이 KNC와 Hereford보다 유의하게 높았으며, Holstein은 pH 7.69~8.83에서, KNC과 Hereford는 8.15에서 각각 유의하게 증가하였다. 4. 精子를 pH가 6.8, 7.1 및 7.4인 SHP液으로 3번 洗滌한 다음 pH 7.4인 mTALP液에서 15분간 培養하였을 때, 精子洗滌液의 吸光度差間 變化는 1차 및 2차 精子洗滌에서 pH 7.1과 7.4가 6.8보다 유의하게 높았으며, 精子尖帽反應率은 pH 7.1 및 7.4가 각각 68.8 및 72.9%로 pH 6.8의 49.1%보다 유의하게 높았다(P<0.05).

• Archives of Pharmacal Research
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• 제16권3호
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• pp.180-185
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• 1993

The acid dissociation constants of certain Schiff bases derived from isatin with p-substituted benzoyl hydrazines and somee amino acids of glycine, $\beta$-and $\alpha$-alanine, valine, $\beta$-phenyl-$\alpha$-alanine and anthranilic acid have been detemined potentiometrically at different temperatures in different aquo-organic solvent mixtures (ethnol, dioxane, dimethyl formamide, methanol, acetone and tetrahydrofurance). The pKa values were demonstrated on the light of the different electornic and steric effects of the substituents and the sovlent characteristics. In all the mixed media used, ionization of the compounds decreased by increasing the mole fraction of the organic cosolvent. Theemodynamic parameters $(\Delta{H}^\circ,\;\Delta{G}^\circ,\;\Delta{S}^\circ)$ were evaluated. The structural effects of the investigated compounds on these parameters were reported and discussed.

• Earthquakes and Structures
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• 제22권5호
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• pp.517-526
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• 2022

In this paper, nonlinear P-delta effects are studied on the seismic performance, and the modal responses of a flexural frame, considering large deformations. Using multiple scales method, the nonlinear differential equations of motion are estimated, and the nonlinear interactions between the frame's degrees of freedom are outcropped. The results of time and frequency domain analyzes of a dynamic model are examined under internal resonance cases, and the linear and nonlinear responses are investigated in each modal cases. Also, changing the modal responses with respect to the amplitude and frequency of the harmonic forces is evaluated. It is shown that the dominant absorption of energy is in the first natural frequency of the frame, in the case of earthquake excitation, and when a harmonic force is applied to the frame, the peaks of the frequency domain responses depending on the frequency of harmonic force are in the first, and second or third natural frequency of the structure.

• 한국식품저장유통학회지
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• 제18권5호
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• pp.678-683
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• 2011

떫은감 분말 첨가 두부의 수율, 품질 및 저장성에 응고제의 종류(magnesium chloride, calcium chloride, calcium sulfate, glucono-${\delta}$-lactone)가 미치는 영향을 조사하였다. Glucono-${\delta}$-lactone으로 응고시킨 두부가 가장 높은 수율, hardness, chewness, crispness, overall acceptability 및 가장 낮은 L값, b값, pH, 침지저장액 탁도, 총균수를 보였다. Calcium sulfate와 calcium chloride으로 응고시킨 두부는 비교적 높은 L과 b값을 나타내었다. Magnesium chloride로 응고시킨 두부는 관능적 품질특성(firmness, taste, overall acceptability)이 glucono-${\delta}$-lactone 응고 두부와 상호 유의적인 차이가 없이 비교적 높게 평가되었다. 이러한 결과로써 glucono-${\delta}$-lactone과 magnesium chloride가 떫은감 분말 첨가 두부 제조에 적합한 응고제로 판단된다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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• pp.235-242
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• 2001

Inelastic seismic response of steel moment frame structures, which are usually quite gravity load and subject to large displacement under severe earthquake, may be severly influenced by the structure P-Δ effects. The P-Δ effect may have an important impact on the dynamic behavior of the structure in the nonlinear seismic analysis. In multi degree of freedom systems P-Δ effects may significantly affect only a subset of stories or a single story alone. Therefore, a story drift amplification of structure is happened by P-Δeffects and such nonlinear dynamic behaviors are very difficult to evaluate in the structures. In this study, two systems having different design methods of steel moment frame structures are investigated to evaluate the P-Δ effects due to gravity load. The plastic hinge formations, maximum rotational ductility demands, and energy distribution will be compared and evaluated following whether the P-Δ effects are considered or not. And design methods are proposed for the prevention of the instability of structures which due to the P-Δ effects.

• 대한약침학회지
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• 제21권4호
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• pp.249-257
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• 2018

Objectives: The hepatotoxicity induced by Acetaminophen (AAP) mostly mediated by effect on oxidative stress parameters. The Zataria multiflora (Z.M) is an herbal medicine with well-known antioxidant effect. The aim of this study is investigation of preventive effects of Z.M and Carvacrol (CAR) on AAP-induced hepatotoxicity in rats. Methods: Rats were randomly divided into four groups including: 1) Control, 2) Acetaminophen (AAP), 3) and 4) CAR. The saline, Z.M (200 mg/kg) and CAR (20 mg/kg) were administrated orally for 6 days, after that AAP (600 mg/kg) was administrated in the $7^{th}$ day. Blood sampling was performed on the first and last days. Also, the liver tissue was removed for evaluation of Malondyaldehide (MDA), Thiol content, Superoxide dismutase (SOD) and Catalase (CAT). Total Protein (tPro), Glutamic Oxaloacetic Transaminase (GOT), Glutamic Pyruvic Transaminase (GPT) and Alkaline Phosphatase (ALP) in liver tissue were evaluated. The changes (${\Delta}$) of enzymes activities were presented. Results: The ${\Delta}GOT$, ${\Delta}GPT$ and ${\Delta}ALP$ in CAR group significantly decreased compared to AAP group (P < 0.01 to P < 0.001) and ${\Delta}GPT$ in Z.M group was significantly reduced in comparison with AAP group (P < 0.05). Also, MDA, Thiol, SOD and CAT levels in treated groups were attenuated compared to AAP group (P < 0.05 to P < 0.001). Conclusion: Z.M and CAR have a powerful hepatoprotective effect. CAR is more effective than Z.M. Based on the results. Z.M and CAR could be potent supplementary agents against hepatotoxicity of AAP in patients.

• 한국식품영양과학회지
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• 제25권6호
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• pp.937-943
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• 1996

저염 명란젓의 shelf-life를 연장하기 위하여 최근 식품 보존제로 주목을 받고있는 chitosan, glucono $\delta-lactone$ 및 sykeeper를 첨가하여 명란젓을 제조한 다음 여러가지 화학적 및 미생물 변화를 분석하였으며 그 결과를 요약하면 다음과 같다. 숙성 중 pH는 숙성 초기에 감소하였다가 숙성이 진행됨에 따라 증가하였으며 sykeeper 첨가는 pH 증가를 억제하였다. 젖산생성은 숙성기간이 증가함에 따라 증가하였으며, sykeeper 첨가는 젖산 생성을 저해하였다. 아미노태 질소는 숙성 5일에 일정수준유지 또는 약간 감소하였다가 그 후 증가하여 숙성 15일에 최고값을 나타낸 후 다시 감소하였으며 sykeeper첨가 명란젓이 가장 높은 생성량을 나타내었다. VBN 및 TMA는 숙성이 진행됨에 따라 증가하였으며 Sykeeper 첨가 명란젓의 생성량이 제일 낮았으며 그 다음이 glucono $\delta-lactone이었다.$ Sykeeper 는 숙성 초기 단계의 TBA 생성을 억제하였으며 또한 미생물의 성장 저해 효과를 나타내었다. Glucono $\delta-lactone$ 및 Sykeeper 첨가는 저염명란젓의 shelf-life를 각각 2일 및 5일 정도 연장하였다.

• 공업화학
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• 제25권1호
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• pp.20-26
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• 2014

양이온성 계면활성제인 tetradecyltrimethylammonium bromide (TTAB) 수용액에서 p-할로겐화 페놀유도체들의 가용화현상을 UV/Vis 분광광도법을 이용하여 연구하였다. 가용화현상에 미치는 치환기, 첨가제 및 온도의 효과를 조사하였다. 모든 페놀유도체의 가용화에 대한 ${\Delta}G^o$와 ${\Delta}H^o$ 값은 측정범위 내에서 모두 음의 값을 나타내었으며, ${\Delta}S^o$ 값은 모두 양의 값을 나타내었다. 특히 이들 열역학 함수값들은 할로겐 치환기의 크기, 전기음성도 및 소수성에 크게 영향을 받았다. n-부탄올 첨가제는 모든 페놀유도체의 가용화를 감소시켰으며, NaCl 첨가제는 오히려 가용화를 촉진시켰다. 이런 결과들로부터 페놀유도체들은 치환기의 성질에 따라 미셀 내에서 가용화되는 위치가 서로 다름을 알 수 있었다.