• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1583-1586
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• 2005

Grinding process is different from other machining processes such as turning, milling and drilling because the cutting edges in a grinding wheel doesn't have uniformity and acts differently on the workpiece at each grinding. This study focus on predicting the geometric error produced during surface grinding and selecting an optimal grinding condition to reduce the geometric error. To achieve the aim, the Taguchi design of experiments was applied and the S/N ratios of each grinding was used for evaluating the results. The predicted quantities by the S/N ratios were compared with the experimental results.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.12 no.2
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• pp.141-162
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• 2001

This study focuses on“Intellectual Freedom”based on the fundamental principles of library user services in Western countries. Particularly, this paper pursues to the philosophical foundations of“the freedom of expression”. It also studies how“the freedom of expression”was restrained by pursuing the definitions of“pornography”and “obscenity”in terms of the court's opinions of The Supreme Court of the United States. Also, PICS and the Communication Decency Acts were discussed.

• Journal of the Korean Ceramic Society
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• v.30 no.4
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• pp.259-264
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• 1993

In this research, the organic tenside R11OSO3- with long alkyl-chain was synthesized, and the intercalationscomplexes fo montmorillonite were formed by the substitution of metallic cation in the montmorilonite by the synthesized organic tenside in following two methods, and the behaviors of the tenside R11OSO3- in the interlamellar space of montmorillonite were studied udner various conditions: 1) In order to protonize the sulfate group of R11OSO3-, the H3O-Montomorillonite, which acts as acid, was synthesized. And then, the organic tenside was intercalated in the interlamellar space of this H3O-Montomorillonite. And thus, the intercalations-complex of R11S-H3O-Montomorillonite was formed. The basal spacing obtained was about 33.84$\AA$. 2) The betaine compound R11OSO3- as a neutral molecule was direct intercalated in the interlamellar space of Na-Montmorillonite under water, and the intercalations-complexes of R11S-H2O-Montmorillonite was synthesized. In this case, the based spacing of bout 23.62$\AA$ was obtained.

• Journal of Microbiology and Biotechnology
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• v.19 no.10
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• pp.1103-1108
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• 2009

The human immunodeficiency virus (HIV)-l protein Tat acts as a transcription transactivator that stimulates expression of the infected viral genome. It is released from infected cells and can similarly affect neighboring cells. The nucleocapsid is an important protein that has a related significant role in early mRNA expression, and which contributes to the rapid viral replication that occurs during HIV-1 infection. To investigate the interaction between the Tat and nucleocapsid proteins, we utilized cDNA micro arrays using pTat and flag NC cotransfection in HEK 293T cells and reverse transcription-polymerase chain reaction to validate the micro array data. Four upregulated genes and nine downregulated genes were selected as candidate genes. Gene ontology analysis was conducted to define the biological process of the input genes. A proteomic approach using PathwayStudio determined the relationship between Tat and nucleocapsid; two automatically built pathways represented the interactions between the upregulated and downregulated genes. The results indicate that the up- and downregulated genes regulate HIV-1 replication and proliferation, and viral entry.

• Journal of the Korean Mathematical Society
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• v.52 no.1
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• pp.191-207
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• 2015

Let $\mathcal{R}$ be a prime ring of characteristic different from 2, $\mathcal{Q}_r$ be its right Martindale quotient ring and $\mathcal{C}$ be its extended centroid. Suppose that $\mathcal{G}$ is a nonzero generalized skew derivation of $\mathcal{R}$, ${\alpha}$ is the associated automorphism of $\mathcal{G}$, f($x_1$, ${\cdots}$, $x_n$) is a non-central multilinear polynomial over $\mathcal{C}$ with n non-commuting variables and $$\mathcal{S}=\{f(r_1,{\cdots},r_n)\left|r_1,{\cdots},r_n{\in}\mathcal{R}\}$$. If $\mathcal{G}$ acts as a Jordan homomorphism on $\mathcal{S}$, then either $\mathcal{G}(x)=x$ for all $x{\in}\mathcal{R}$, or $\mathcal{G}={\alpha}$.

• Korean Journal of Child Studies
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• v.28 no.4
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• pp.19-33
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• 2007

This study examined the effects of closeness of peer relationships on intersubjectivity in young children's joint story making of wordless picture books. The joint story making activity of 32 five-year-old children was videotaped and transcribed, and the structure and negotiation types of interaction were examined by Goncu's (1993a) measure of intersubjectivity. Results showed (1) closeness of peer relationship was related to the structure of intersubjectivity children working with very close peers exhibited more turns. (2) Children working with very close peers used more extension and acceptance negotiation types, whereas the children working with non-close peers used more building-on of own ideas and irrelevant acts of negotiation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.318-321
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• 2002

This paper presents a proper condition to achieve high conversion efficiency using PC1D simulator on sri-crystalline Si solar cells. Various efficiency influencing parameters such as rear surface recombination velocity and minority carrier diffusion length in the base region, front surface recombination velocity, junction depth and doping concentration in the Emitter layer, BSF thickness and doping concentration were investigated. Optimized cell parameters were given as rear surface recombination of 1000 cm/s, minority carrier diffusion length in the base region 200 $\mu\textrm{m}$, front surface recombination velocity 100 cm/s, sheet resistivity of emitter layer 100 Ω/$\square$, BSF thickness 5 $\mu\textrm{m}$, doping concentration 5${\times}$10$\^$19/ cm$\^$-3/. Among the investigated variables, we learn that a diffusion length of base layer acts as a key factor to achieve conversion efficiency higher than 19 %.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.519-524
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• 2003

In this paper we discuss the dynamic characteristics of the in-arm type hydropneumatic suspension unit(ISU). For this, two accurate models are introduced. The first one is the Benedict-Webb-Rubin equation which is adopted for the spring behavior of a real gas. This equation is applicable for the high pressure of the nitrogen gas which acts as a spring in ISU system. The second one describes the behavior of a damper, which is divided into four parts - jounce-loading, jounce-unloading, rebound-loading and rebound-unloading. This approach gives a good approximation of the real damper system. For the comparison purpose, the numerical results of the dynamic behavior of ISU system using a real gas and an ideal gas are given in the paper.

• BMB Reports
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• v.43 no.6
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• pp.407-412
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• 2010

Homeodomain (HD) is a highly conserved DNA-binding domain composed of helix-turn-helix motif. Drosophila Vnd (Ventral nervous system defective) containing HD acts as a regulator to either enhance or suppress gene expression upon binding to its target sequence. In this study, kinetic analysis of Vnd binding to DNA was performed. The result demonstrates that DNA-binding affinity of the recombinant protein containing HD and NK2-specific domain (NK2-SD) was higher than that of the full-length Vnd. To access whether phosphorylation sites within HD and NK2-SD affect the interaction of the protein with the target sequence, alanine substitutions were introduced. The result shows that S631A mutation within NK2-SD does not contribute significantly to the DNA-binding affinity. However, S571A and T600A mutations within HD showed lower affinity for DNA binding. In addition, DNA-binding analysis using embryonic nuclear protein also demonstrates that Vnd interacts with other nuclear proteins, suggesting the existence of Vnd as a complex.

• Advances in Traditional Medicine
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• v.9 no.4
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• pp.269-276
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• 2009

Black pepper (family Piperaceae), is called king of spices because it is one of the oldest spice and alone accounts for about 35% of the world's total spice trade. The pepper is used in Ayurvedic medicine for the treatment of various ailments particularly neurological, broncho-pulmonary and gastrointestinal disorders. Pepper has also been reported to have various pharmacological actions but recently, it is highlighted as a bioavailability enhancer. This results in higher plasma concentration of drugs, nutrients, ions and other xenobiotics, rendering them more bioavailable for physiological as well as pharmacological actions in the body. Numerous scientific studies reported that piperine; a main bioactive compound of pepper, is responsible for its bioavailability enhancing property. It's a well known fact that pepper enhances bioavailability by inhibition of microsomal enzyme system but other mechanisms are also responsible to acts as a bioavailability enhancer. The brief overview of the mechanism of action of pepper as well as its applications as bioavailability enhancer is given in the present article.