• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.9
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• pp.561-565
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• 2014

Thermoelectric materials have been the topic of intensive research due to their unique dual capability of directly converting heat into electricity or electrical power into cooling or heating. Bismuth telluride ($Bi_2Te_3$) is the best-known commercially used thermoelectric material in the bulk form for cooling and power generation applications In this work we focus on the large scale synthesis of nanostructured undoped bulk nanostructured $Bi_2Te_3$ materials by employing a novel bottom-up solution-based chemical approach. Spark plasma sintering has been employed for compaction and sintering of $Bi_2Te_3$ nanopowders, resulting in relative density of $g{\cdot}cm^{-3}$ while preserving the nanostructure. The average grain size of the final compacts was obtained as 200 nm after sintering. An improved NS bulk undoped $Bi_2Te_3$ is achieved with sintered at $400^{\circ}C$ for 4 min holding time.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.450-458
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• 2018

The purpose of this study is to investigate the impact of university knowledge capital on the local business activity in the Korean local governments in the year 2015. We found that the increase of the standard deviation of university patent, scientific publications, incumbent firms, and industrial property rights raised the number of new knowledge-intensive firms to 15%, 11%, 54%, and 22%, respectively, in the local economy. In addition, the coefficient which reflects the interaction effects of the knowledge capital between universities and local industries was significant in the given area in the year. On the other hand, in the control variables, the coefficients for the size of local government, population density, and percentage of 20s~40s out of the total population in the local government were significant, showing above 90% level except for the variable of the distance between a local government and Seoul. In particular, when the knowledge capital of the university and industry coexists, the synergistic effect which has influence on the foundation of knowledge-intensive firms was meaningful despite the small scale, and these two types of knowledge capital could be complementary in creating new knowledge-intensive firms in the Korean local economy.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.11-14
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• 2003

To evaluate the ewe reproductive performances of three Iranian local sheep breeds, namely Moghani, Chal and Zel, 27 rams and 473 ewes were used as the foundation flock in a crossbreeding program. The three breeds were crossed amongst themselves reciprocally. Ram breed and ewe breed showed a two-way interaction on apparent fertility. The Zel ewes showed higher fertility than the Chal and Moghani ewes (94.4 vs 77.3 and 84.6%). Prolificacy among main and individual mating groups were not significantly different (p>0.05). Zel ewes were 22.3 and 14.8% more reproductive (p<0.05) than Chal and Moghani ewes, respectively. Zel and Moghani ewes showed higher (p<0.05) ewe productivity than Chal ewes. Ram breed had a significant (p<0.05) effect on ewe efficiency. The Zel rams were not completely successful to mate with Chal ewes, this caused a to way-interaction between ram and ewe breeds. The Zel ewes mated with Chal and Moghani rams showed 26.1 and 28.5% more efficiency than those mated with Zel rams. This observation strongly supports the use of crossbreeding to improve the efficiency of the Zel ewes. With decreasing lamb mortality, through supplemented feeding of lambs in pre-weaning period, and increasing litter weight, through crossbreeding, it should be possible to improve the efficiency of Zel ewes even better than Chal and Moghani ewes. Small body size of Zel ewes that needs the lower maintenance requirements would be a well advantageous to using Zel ewes as the dam herd to produce commercial lambs in north area of Iran.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.367-375
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• 2006

Sequencing Batch Reactor (SBR) is well adopted for community wastewater treatment for its simplicity, performance and various advantageous treatment options. SBR is now drawing attention for its process modification such as coupled with membrane bioreactor, reverse osmosis or applying different media to achieve high removal efficiency. This study focused on the improved efficiency of carbon, nitrogen and phosphorous removal by applying zeolite materials called bioceramics to the SBR. Two laboratory-scale SBR units were operated in the same operating conditions - one with bioceramics called Bioceramic SBR (BCSBR) and the other without bioceramics used as control. Routine monitoring of COD, TP, $NH_3-N$, $NO_3-N$ was performed throughout this study. COD removal was about 80% to 100% and phosphorous removal was about 60% in the process whereas $NH_3-N$ removal efficiency was found to be 99.9% in the BCSBR unit. Addition of bioceramics also improved sludge characteristics such as sludge dewaterability, specific gravity and particle size. BCSBR can withstand high ammonia shock loading leading to the better treatment capacity of high ammonia containing wastewater. The cause of improved removal efficiencies within the biological reactor could be attributed to the biochemosorption mechanisms of bioceramics. Absorption/adsorption or desorption capacity of bioceramics was tested through laboratory experiments.

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.59-67
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• 2014

With increasing underwater structure construction, there is high interest in offshore foundation and underwater grout and various study has been done in this area. For grout materials constructed underwater, it may be washed away by water or easily disturbed and material separation phenomenon during curing period always happens. As a result, it is difficult to ensure construction quality and this has a significant influence on the design strength of structure. In this study, to understand application effects of anti-washout admixture for the preplaced construction method, where grout is injected in monopile after filled with aggregates, laboratory tests on bleeding and compressive strength of anti-washout admixture were performed under various test conditions varying size of aggregate, water and cement ratio and admixture, and test results were compared and evaluated.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.13
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• pp.5579-5582
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• 2015

Background: Sale of single cigarettes is an important factor for early experimentation, initiation and persistence of tobacco use and a vital factor in the smoking epidemic in India as it is globally. Single cigarettes also promote the sale of illicit cigarettes and neutralises the effect of pack warnings and effective taxation, making tobacco more accessible and affordable to minors. This is the first study to our knowledge which estimates the size of the single stick market in India. Materials and Methods: In February 2014, a 10 jurisdiction survey was conducted across India to estimate the sale of cigarettes in packs and sticks, by brands and price over a full business day. Results: We estimate that nearly 75% of all cigarettes are sold as single sticks annually, which translates to nearly half a billion US dollars or 30 percent of the India's excise revenues from all cigarettes. This is the price which the consumers pay but is not captured through tax and therefore pervades into an informal economy. Conclusions: Tracking the retail price of single cigarettes is an efficient way to determine the willingness to pay by cigarette smokers and is a possible method to determine the tax rates in the absence of any other rationale.

• Journal of Oriental Neuropsychiatry
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• v.21 no.4
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• pp.151-161
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• 2010

Objectives : This study aimed to evaluate any clinical studies regarding the herbal medicine for dementia focusing on Korean literature for future rigorous clinical research. Methods: Every article relevant to dementia was initially obtained from oriental medical related journals by electronic search at journal web sites or manual searches. Journals were limited to those registered with the Korea Research Foundation. From initial findings. two independent reviewers selected clinical articles and these articles were further analyzed separately by predefined criteria according to prospective and retrospective studies. For randomized controlled trial and non randomized controlled trial. quality assessment was also conducted. Results: From ninety seven patients initially obtained articles. twenty three patients were finally analyzed. One article was randomized controlled study. Four articles were prospective whereas eighteen patients were retrospective. In the qualitative evaluation of prospective articles. there was deduction regarding pre-calculated study size and prospective data collecting. Assessment measurement most frequently used was Mini Mental State Examination. The order of frequency of use herbs were identified. Conclusions : According to our study. the herbal medicine for dementia in general showed a positive effect in the cognitive aspects of dementia patients. Further well-designed randomized controlled studies should be conducted.

• The Research Journal of the Costume Culture
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• v.25 no.6
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• pp.880-892
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• 2017

In this study, the appearance change and the heat moisture transfer properties of knitted fabric by yarn shrinkage were examined to obtain useful data on the development of thermo-sensitive functional materials. Eleven types of knitted fabric were knitted using highly bulky acrylic-blended yarn. After shrinking the specimens using dry heat treatment, the appearance change and thickness were measured. An HEC simulator was adopted for measuring the heat moisture transfer properties of specimens by yarn shrinkage. When holes were arranged vertically in the mesh structure, the specimens with 2,500 and 5,000 holes showed high percent change of hole area, appearance, and thickness. When holes were diagonally arranged in the mesh structure, the percent change of hole area in the specimen with 1,250 holes was larger than the one with 2,500 holes. However, the dimensional stability of the specimen with 2,500 holes was better because of its smaller appearance and thickness change. In the tuck structure, the percent change of hole area in the specimen with 625 and 416 holes was relatively large compared with the appearance and thickness change. Furthermore, the hole size in the tuck structure was smaller than that in the mesh structure but the percent change of hole area was larger. Therefore, it was proved that the tuck structure is more suitable than the mesh structure for developing thermo-sensitive functional materials. Heat moisture transfer property test verified that the change of hole area by yarn shrinkage enabled obtaining the thermal effect due to the distinct temperature difference in the inner layer.

• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2585-2593
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• 2020

Swift heavy ion (SHI) beam irradiation can generate desirable defects in materials by transferring sufficient energy to the lattice that favours huge possibilities in tailoring of materials. The effect of Ag¹⁵⁺ ion irradiation with energy 200 MeV on spray deposited V₂O₅ thin films of thickness 253 nm is studied at various ion doses from 5 × 10¹¹ to 1 × 10¹³ ions/㎠. The XRD results of pristine film confirmed orthorhombic structure of V₂O₅ and its average crystallite size was found to be 20 nm. The peak at 394 cm^-1 in Raman spectra confirmed O-V-O bonding of V₂O₅, whereas 917 cm^-1 arise because of distortion in stoichiometry by a loss of oxygen atoms. Raman peaks vanished completely above the ion fluence of 5 × 10¹² ions/㎠. Optical studies by UV-Vis spectroscopy shows decrement in transmittance with an increase in ion fluence up to 5 × 10¹² ions/㎠. The red shift is observed both in the direct and indirect band gaps until 5 × 10¹² ions/㎠. The surface topography of the pristine film revealed sheath like structure with randomly distributed spherical nano-particles. The roughness of film decreased and the density of spherical nanoparticles increased upon irradiation. Irradiation improved the conductivity significantly for fluence 5 × 10¹¹ ions/㎠ due to band gap reduction and grain growth.

• Advances in nano research
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• v.10 no.5
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• pp.449-460
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• 2021

Flexoelectricity is an interesting materials' property that is more touchable in small scales. This property beside the sandwich structures placed in the center of scientists' attention due to their extraordinary effects on the mechanical properties. Furthermore, in the passage of decades, more elaborated sandwich structures took into consideration results from using honeycomb core. This kind of structure, inspiring from honeycomb core, provides more stiffness to weight ratio, which plays a crucial role in different industries. In this paper, based on the Love-Kirchhoff's hypothesis, Hamilton's principle, modified couple stress theory and Fourier series analytical method, equations of motion for a sandwich plate containing a honeycomb core integrated by two face-sheets have derived and solved analytically. The equations of both face sheets have derived by flexoelectricity consideration. Moreover, it should be noticed that the whole structure rests on the visco-Pasternak foundation. Conducting current research provided an acceptable and throughout study based on flexoelectricity to address the effect of materials' characteristics, length-scale parameter, aspect, and thickness ratios and boundary conditions on the natural frequency of honeycomb sandwich plates. Also, based on the presented figures and tables, there is a close agreement between previous studies and recent work. Due to the high ratio of strength to weight, current model analyzing is capable of taking into account for different vehicles' manufacturing in a high range of industries.