• Structural Engineering and Mechanics
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• v.59 no.3
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• pp.503-526
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• 2016

In-plane and out-of-plane free vibration analysis of Timoshenko curved beams is addressed based on the isogeometric method, and an effective scheme to avoid numerical locking in both of the two patterns is proposed in this paper. The isogeometric computational model takes into account the effects of shear deformation, rotary inertia and axis extensibility of curved beams, and is applicable for uniform circular beams, and more complicated variable curvature and cross-section beams as illustrated by numerical examples. Meanwhile, it is shown that, the $C^{p-1}$-continuous NURBS elements remarkably have higher accuracy than the finite elements with the same number of degrees of freedom. Nevertheless, for in-plane or out-of-plane vibration analysis of Timoshenko curved beams, the NURBS-based isogeometric method also exhibits locking effect to some extent. To eliminate numerical locking, the selective reduced one-point integration and $\bar{B}$ projection element based on stiffness ratio is devised to achieve locking free analysis for in-plane and out-of-plane models, respectively. The suggested integral schemes for moderately slender models obtain accurate results in both dominated and non-dominated regions of locking effect. Moreover, this strategy is effective for beam structures with different slenderness. Finally, the influence factors of structural parameters of curved beams on their natural frequency are scrutinized.

• Nuclear Engineering and Technology
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• v.27 no.5
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• pp.743-752
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• 1995

This paper investigates the effects of fuel groupings in the coupled internals and core model on the internals and fuel responses due to pipe breaks. The 177 fuel assemblies for Korean standard nuclear power plant are grouped into several stick models and the responses of internals components are calculated. The analysis results show that the fuel model groupings in the coupled internals and core model have no significant effects on the internals and fuel responses for pipe break excitation. Also, in order to determine the feasibility of constructing a single equivalent stick representation of In or more adjacent fuel bundles, the reduced models, each of which employs a different stiffness lumping rule, are constructed. It is shown that the equivalent stiffness calculated to get the first natural frequency of the original model while preserving net gap between grouping centers gives the minimum modelling error.

• Journal of the Korean Chemical Society
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• v.60 no.3
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• pp.169-176
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• 2016

In a borate buffer solution, the growth kinetics and the electronic properties of passive film on aluminum were investigated, using the potentiodynamic method, chronoamperometry, and multi-frequency electrochemical impedance spectroscopy. The corrosion of aluminum was heavily influenced by the degree of oxygen concentration because of the increasing reduction current. The oxide film formed during the passivation process of aluminum has showed the electronic properties of n-type semiconductor, which follow from the Mott-Schottky equation. It was found out that the passive film (Al(OH)₃) of Al formed in the low electrode potential changes to Al₂O₃ while the electrode potential increases. The growth kinetics data as measured by chronoamperometry suggests a mechanism in which the growth of the film of Al₂O₃ is determined by field-assisted transport of ions through the film.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.260-266
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• 2011

This study was carried out to control biennial weed which gives a lot of damage to landscaped and early growth of lawns in early spring. The results obtained from the mowing experiment are as follows. (1) Average of occurrence rate of weed species of the total treatments was 17.9%, (2) Occurrence rate of weed species was as 24.7% at 12.5 mm low mowing section. The rate indicates that the lowest weed depression effect was appeared at the lowest mowing among 4 mowing sections. (3) Occurrence rate of weed species was 10.6% at 22.5 mm mowing section. The highest weed depression effect among the 4 mowing sections was observed at the 22.5 mm mowing section. (4) Occurrence rates of weed species were 18.2% and 18.3% at 32.5 mm and 42.5 mm high mowing section, respectively.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.472-477
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• 1999

To elucidate the action of the cholinergic and adrenergic nerve on isolated gastric fundus smooth muscle of rabbit, the effects of electrical transmural stimulation were investigated in the presence of atropine, cholinergic receptor blocker; phentolamine, nonselective ${\alpha}$-adrenergic receptor blocker; propranolol, nonselective ${\beta}$-adrenergic receptor blocker and L-arginine from the isometric contraction of physiological recording system. 1. The contractile response induced by electrical transmural stimulation was increased as the frequency(1~32Hz)-dependent manner on the isolated gastric fundus smooth muscle. 2. The contractile response induced by electrical transmural stimulation was markedly inhibited by the pretreatment of atropine($1{\mu}M$). 3. The contractile response induecd by electrical transmutal stimulation was inhibited by the pretreatment of phentolamine($1{\mu}M$). 4. The relaxative response induced by electrical transmural stimulation on presence of atropine ($1{\mu}M$) was inhibited by the pretreatment of propranolol($1{\mu}M$). 5. The relaxative responses on precontraction induced by histamine($10{\mu}M$) with guanethidine ($50{\mu}M$) and atropine($1{\mu}M$) by electrical transmural stimulation were increased by L-arginine (1mM). These findings suggest that it was the excitatory action of cholinergic and ${\alpha}$-adrenergic nerve, and the inhibitory action of ${\beta}$-adrenergic nerve and nonadrenergic noncholinergic nerve on the isolated gastric fundus smooth muscle of rabbit.

• Korean Journal of Veterinary Research
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• v.39 no.3
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• pp.448-454
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• 1999

The regional distribution and relative frequency of the endocrine cells in the pancreas of the bean goose were investigated by immunohistochemical methods using 6 types of the specific antisera. Spindle shaped serotonin-immunoreactive cells were detected in the exocrine portions. Spherical or spindle shaped glucagon-immunoreactive cells were observed in the exocrine and dark and mammalian type islets. In the dark type islets, numerous cells were dispersed throughout whole islets but they were located in the peripheral regions of the mammalian type islets. No glucagon-immunoreactive cells were detected in light type islets. Round or spherical shaped insulin-immunoreactive cells were observed in the exocrine and dark, light and mammalian type islets. They were observed in the exocrine regions with a few numbers. Extremely rare cells were detected in central portion of the dark type islets but moderate to numerous cells were found in the central regions of the mammalian and light type islets, respectively. Spherical or spindle shaped somatostatin-immunoreactive cells were observed in the exocrine and dark, light and mammalian type islets. A few single cells were detected in the exocrine portions. In the dark type islets, numerous cells were dispersed throughout whole islets but a few to moderate numbers of cells were located in the peripheral regions of the light and mammalian type islets. Moderate numbers of the bovine pancreatic polypeptide-immunoreactive cells were found in the exocrine portions with round, spherical or spindle shape. But no bovine Sp-1/chromogranin-immunoreactive cells were observed in this study.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.221-228
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• 2000

We performed this study to determine the effect of Bu-Zhong-Yi-Qi-Tang, as a prescription of traditional Oriental medicine, and its major ingredients on jejunal crypt survival, endogenous spleen colony formation, apopotosis in jejunal crypt cells, lethality and hematological change of mice irradiated with high and low dose of Y-radiation. Bu-Zhong-Yi-Qi-Tang administration before irradiation protected the jejunal crypts (p<0.0001), increased the formation of endogenous spleen colony (p<0.05) and reduced the frequency of radiation-induced apoptosis (p<0.05). The survival rate and mean survival time of the groups treated with Bu-Zhong-Yi-Qi-Tang within 30 days after the treatment were far better than the irradiation control group. In the experiment on the effect of ingredients of Bu-Zhong-Yi-Qi-Tang, the result indicated that the extract of Rensan (Panax ginseng), Danggui (Angelica sinensis), Shengma (Cimicifuga heracleifolia) and Chaihu (Bupleurum falcatnosa) might have a major radioprotective effect. Although the mechanisms of this inhibitory effect remain to be elucidated, these results indicated that BU-Zhong-Yi-Qi-Tang might be a useful radioprotector, especially since it is a relatively nontoxic natural product. Further studies are needed to characterize better the protective nature of Bu-Zhong-Yi-Qi-Tang extract and its ingredients.

• Korean journal of food and cookery science
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• v.26 no.4
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• pp.450-457
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• 2010

A survey was conducted to determine the relationship between BMI and the dining out behaviors of 316 university students in Seoul area for May and September, 2006. The subjects included 114 males and 202 females. General characteristics and BMI determined that of the students 56 (17.7%) were underweight, 222 (70.3%)were normal, 23 (7.3%) were overweight, and 15 (4.7%) were obese. There were differences in BMI according to age, sex, and major. Students majoring in natural science and engineering were 58.3% and 51% normal weight, respectively, and the next most common weight class was overweight. The non smoking group showed had primarily normal weight subjects followed by underweight-subjects, but the smoking group had primarily normal weight subjects followed by overweight subjects (P<0.001). The frequency of dining out for breakfast significantly correlated with BMI (P<0.05). The group that frequently dined out for breakfast were primarily of normal weight followed by overweight subjects, but the group that rarely dined out for breakfast were primarily of normal weight followed by underweight subjects(21.4%). Groups whose criteria for selecting dining out meals were flavor and price showed a higher percentage of underweight subjects than other groups. The group whose motivations for choosing dining out meals were convenience and habit showed a higher percentage underweight subjects than other motivations. The group that selected the Western food menu for dining out showed a higher percentage of underweight subjects than other food menu groups. And, the groups that selected Japanese and Korean food were primarily of normal weight followed by underweight subjects, but the result was not significant.

• Korean Journal of Human Ecology
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• v.17 no.5
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• pp.975-987
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• 2008

The purpose of this thesis is to conduct a thorough research on shoes of 2000s, understand the changes and analyze the differences and the characteristics of the shoe designs of the past and present in order to predict and indicate the future direction of the women shoe designs. The shoes of the millennium not only kept the old fashioned shapes but also showed futuristic shapes. With the increasing importance of shoes in fashion, shoes with various images were created. As far as the materials are concerned, natural materials and artificial materials were both used. The colors were vivid and the futuristic colors. On the other hand, pastel toned colors and romantic colors were used in many different designs and shapes regardlees of the seasons. Straps and hills differed from the oldies. Heavy decorations were added to strap shoes to form a whole new design and hills show geometrical platforms or the avantgarde like heights. Feminine images overwhelmed the shoe designs of the millennium. To elaborate, Pumps displayed feminine images the most for it showed a high frequency number regardless of the seasons. Shoes are presented in aesthetical perspective rather then functional or practical perspectives that are based on human nature. Cultural, social, environmental and some part religious factors had a great influence on the evolution on the shoes. Especially in the 2000s, future oriented concepts were implemented on shoe designs, resulting a wider range of expressiveness and in the end leading to a more creative shoe designing. Changes in shoe designs could be pointed out in many ways according to the shapes materials, colors, modeling of decorations or also with the diverting trends.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.304-312
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• 2013

The thermotolerant methylotrophic yeast Hansenula polymorpha is attracting interest as a potential strain for the production of recombinant proteins and biofuels. However, only limited numbers of genome engineering tools are currently available for H. polymorpha. In the present study, we identified the HpPOL3 gene encoding the catalytic subunit of DNA polymerase ${\delta}$ of H. polymorpha and mutated the sequence encoding conserved amino acid residues that are important for its proofreading 3'${\rightarrow}$5' exonuclease activity. The resulting $HpPOL3^*$ gene encoding the error-prone proofreading-deficient DNA polymerase ${\delta}$ was cloned under a methanol oxidase promoter to construct the mutator plasmid pHIF8, which also contains additional elements for site-specific chromosomal integration, selection, and excision. In a H. polymorpha mutator strain chromosomally integrated with pHIF8, a $URA3^-$ mutant resistant to 5-fluoroorotic acid was generated at a 50-fold higher frequency than in the wild-type strain, due to the dominant negative expression of $HpPOL3^*$. Moreover, after obtaining the desired mutant, the mutator allele was readily removed from the chromosome by homologous recombination to avoid the uncontrolled accumulation of additional mutations. Our mutator system, which depends on the accumulation of random mutations that are incorporated during DNA replication, will be useful to generate strains with mutant phenotypes, especially those related to unknown or multiple genes on the chromosome.