• Archives of Pharmacal Research
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• 제2권1호
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• pp.1-8
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• 1979

The flow rate of various sand through circular orifice can be measured from a knowledge of a few easily measurable properties of the system. These are the orifice column and particle diameters, the angle of inclination of the orifice with the horizontal and an angle of repose of the granular sand material. Straight lines were obtained when the logarithm of the flow rate was plotted versus the logarithm of orfice diameter. No influence of excessive compaction and bed height was observed and the flow rate increased with decrease of particle diameter. The profile of flow developed the edge of the aperture in a way independent of its size. Linear relationship was observed between the angle of inclination of the orifice and the flow rate.

• Macromolecular Research
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• 제13권1호
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• pp.39-44
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• 2005

Ion-exchange polymeric stationary phases presenting amino acid and amino groups were prepared by the surface grafting of glycidyl methacrylate onto a silica gel surface and subsequent amination. Three kinds of amino acids-L-arginine (Arg), D-lysine (Lys), and D-histine (His)-were used in this study. An ion-exchange polymeric stationary phase presenting ethylene diamine (EDA) was also prepared by surface graft polymerization. Separation of the model proteins bovine serum albumin (BSA), chick egg albumin (CEA), and hemoglobin (Hb) was performed using the amino acid- and amine-derived columns. In separating the CEA/BSA mixture, the resolution time of BSA was longer than that of CEA when using the EDA column, whereas the resolution time of BSA was shorter than that of CEA when using the Arg, Lys, and His columns. In the separation of the Hb/BSA mixture, the resolution time of BSA was longer than that of Hb in the EDA column, whereas the resolution time of BSA was shorter than that of Hb in the amino acid columns (D-Lys, L-Arg, and D-His).

• Geomechanics and Engineering
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• 제31권5호
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• pp.489-503
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• 2022

A 1257-m-long irregular deep foundation pit located in the central of Nanjing, China was constructed using the combined full-width and half-width top-down method. Based on the long-term field monitoring data, this study analyzed the evolution characteristics of the vertical movement of the columns, internal force of the struts, and axial force of the structural beam and slab. The relevance of the three mentioned above and their relationship with the excavation process, structural system, and geological conditions were also investigated. The results showed that the column uplift was within the range of 0.08% to 0.22% of the excavation depth, and the embedded depth ratio of the diaphragm wall and the bottom heave affected significantly on the column uplift. The differential settlement between the column and diaphragm wall remained unchanged after the base slab was cast. The final settlement of the diaphragm wall was twice the column uplift. The internal force of the struts did not varied monotonically but was related to numerous factors such as the excavation depth, number of struts, and environmental conditions. Additionally, the dynamic force and deformation of the columns, beams, and slabs were analyzed to investigate the inherent relationship and variation patterns of the responses of different parts of the structure.

• Korean Chemical Engineering Research
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• 제43권2호
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• pp.272-277
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• 2005

직경이 0.152 m이고 높이가 3.5 m인 기-액 향류 흐름 기포탑에서 기포의 물성과 흐름의 거동을 고찰하고 진단하였다. 기체와 액체의 유속 그리고 기포의 분산형태(even, wall-side, central or asymmetric distribution)가 반응기 내부에서 기포의 크기, 빈도수, 상승속도와 체류량 등 기포특성에 미치는 영향을 이중 전기 저항 탐침법을 이용하여 측정 검토하였다. 기포의 크기, 빈도수와 체류량은 기체나 액체 유속의 증가에 따라 증가하였다. 기포의 상승속도는 기체 유속의 증가에 따라 증가하였지만, 액체 유속의 증가에 따라서는 감소하였다. 기포 크기 분포의 균일성이나 체류량은 기포 분산판에서 기포의 분산형태가 균일분포에서 벽면, 중앙 그리고 비대칭 분산으로 변화함에 따라 감소하였다. 기포의 체류량과 분포에 대한 균일성을 고려하면, 기포의 중앙 분산 형태가 비대칭 분산 형태보다는 유리하며, 벽면 분산형태분산보다는 좋지 않았다.

• 한국연초학회지
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• 제30권2호
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• pp.109-116
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• 2008

Mutagenicity of cigarette smoke is one of the major health concerns related to smoking. Reduction of the components comprising mutagenic activity in cigarette mainstream smoke can be expected to bring about reduced risk of smoking. The purpose of this study is to isolate mutagenic compounds and to investigate the relative contribution to allover mutagenicity of smoke to find clues for the effective elimination of the components. Cigarette smoke condensate (CSC) was obtained from total particulate matter (TPM) of mainstream smoke, and several fractions fractionated from CSC were made by combination of cation exchange chromatograph and reverse-phase chromatography. The mutagenic activity of these fractions was assessed using Salmonella mutagenicity assay with S. typimurium TA98 strain in the presence of metabolic activation system (S-9). The fractions isolated by cation exchange and reverse-phase column showed relatively high mutagenic activity. The basic and hydrophilic fraction 9 showed approximately 33% of mutagenic activity of CSC and its specific activity was 2,459 revertants/mg TPM. These results suggest that hydrophilic cation exchanger and/or other adsorbents possessing similar properties may be used to remove the mutagenic compounds from mainstream smoke.

• 한국동물위생학회지
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• 제29권2호
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• pp.111-122
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• 2006

A direct, accurate and sensitive chromatographic analytical method for quantitative determination of four fluoroquinolones (norfloxacin, cirprofloxacin, danofloxacin and enrofloxacin) in chicken, pork and beef edible muscle is proposed in the present study. The developed method was successfully applied to the determination of enrofloxacin, as the main component of commercially available veterinary drugs. The samples were homogenized and the antimicrobials were added, then they were extracted twice with dichloromethane. Fluoroquinolone antibiotics were separated on an agilent $250x4mm,\;C_{18},\;5{\mu}m$, analytical column, at $25^{\circ}C$. The mobile phase consisted of a mixture of DW : acetonitrile : triethylamine(80:19:1%, v/v, pH 3.0) leading to retention times less than 14 min. at a flow rate 0.5 ml/min. These fluoroquinolones were detected by liquid chromatography with fluorescence at 290 nm excitation and 465 nm emission. The limits of quantification in each edible muscle (chicken, pork, and beef) were 0.32-6.54 ng/g. Using 0.5 g of each sample, average recovery rates at fortification levels of 0.05, 0.1 and 0.2 ${\mu}g/ml$ ranged 70.14-71.71% for NFX, 71.87-73.89% for CFX, 82.16-92.35% for DFX, and 90.13-98.12 for EFX This is a simple and economic method to quantify the presence of NFX, CFX, EFX and DFX in edible muscle of animal origin.

• 한국연초학회지
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• 제31권1호
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• pp.45-50
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• 2009

In this study, a simple gradient RRLC method for rapid determination of carbonyl compounds of cigarette smoke was developed. Within 10 min, 8 carbonyl compounds have been separated and identified on ZORBAX Eclipse XDB-C18 column ($4.6{\times}50\;mm$, $1.8\;{\mu}m$) with gradient elution using water and acetonitrile as a mobile phase. RRLC was used for the quantification of carbonyl compounds in mainstream smoke of 3R4F reference cigarette, and evaluated those efficiencies in the recovery, repeatability and reproducibility. The correlation coefficients ($r^2$) for calibration curves of carbonyl compounds were over 0.9998. The developed RRLC method was successfully applied to the analysis of smoke samples and the recoveries of carbonyl compounds were in the range of 97.5~102.1% with RSD<3.1%.

• Archives of Pharmacal Research
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• 제22권2호
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• pp.189-193
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• 1999

Reversed-phase high-performance liquid chromatography/mass spectrometry (HPLC/MS) with an eletcrospray ionization (ESI) interface was applied to the identification of metabolites of IY81149 in the rat plasma. Fragments obtained using collision-induced dissociation (CID) in both positive and negative modes were utilized to elucidate the structure of metabolites. The eluent from the conventional HPLC column was split and directly introduced into an ESI-mass spectrometer for the identification of the structures. the CID technique allowed the sensitive identification of sulfonyl-IY81149 and hydroxy-IY81149 from the rat plasma.

• Steel and Composite Structures
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• 제30권2호
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• pp.149-169
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• 2019

A new form of composite column, concrete-filled round-ended steel tubes (CFRTs), has been proposed as piers or columns in bridges and high-rise building and has great potential to be used in civil engineering. Hence, the objective of this paper presents an experimental and numerical investigation on the flexural behavior of CFRTs through combined experimental results and ABAQUS standard solver. The failure mode was discussed in detail and the specimens all behaved in a very ductile manner. The effect of different parameters, including the steel ratio and aspect ratio, on the flexural behavior of CFRTs was further investigated. Furthermore, the feasibility and accuracy of the numerical method was verified by comparing the FE and experimental results. The moment vs. curvature curves of CFRTs during the loading process were analyzed in detail. The development of the stress and strain distributions in the core concrete and steel tube was investigated based on FE models. The composite action between the core concrete and steel tube was discussed and clarified. In addition, the load transfer mechanism of CFRT under bending was introduced comprehensively. Finally, the predicted ultimate moment according to corresponding designed formula is in good agreement with the experimental results.

• Steel and Composite Structures
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• 제31권3호
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• pp.291-301
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• 2019

Pure torsion loading conditions were not frequently occurred in practical engineering, but the torsional researches were important since it's the basis of mechanical property researches under complex loading. Then a 3D finite element model with precise material constitutive models was established, and the effectiveness was verified with test data. Parametric studies with varying factors as steel yield strength, concrete strength and sectional height-width ratio, were performed. Internal stress state and the interaction effect between encased steel tube and the core concrete were analyzed. Results indicated that due to the confinement effect between steel tube and core concrete, the torsional strength of CFT columns was greatly improved comparing to plain concrete columns. The steel ratio would greatly influence the torque share between the steel tube and the core concrete. Then the torsional strength calculation formulas for core concrete and the whole CFT column were proposed. The proposed formula could be simpler and easier to use with guaranteed accuracy. Related design codes were more conservative than the proposed formula, but the proposed formula presented more satisfactory agreement with experimental results.