• Journal of the Korean Ceramic Society
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• v.24 no.1
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• pp.47-55
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• 1987

The purpose of this work is to establish the basic calibration data for the efficiency of grinding by investigating the Bond's Work Index employing Korean Kaolin as a reference mateial with the laboratory-scale ball mill. A small ordinary ball mill has a dimension of 133 inside diameter and 144mm long. The analysis of the experimental results in this work sets up a equivalent calibration method with the laboratory-scale ball mill to those with special mill. The theoretical expression, derived from the rate equation proposed by Miwa, is obtained to anticipitate the stable revolution number for the next grinding cycle. The proposed equation is more systematic and acurate than lshihara's empirical equation is more systematic and acurate than lshihara's empirical equation for the measurement of gindability of a ball mill.

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.1
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• pp.63-71
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• 2023

In this study, the structural characteristics of sericin recovered from wastewater released from the silk textile industry (Plant sericin) were comparatively analyzed with those of sericin extracted from a silkworm cocoon produced in a laboratory (Lab sericin). To prepare Plant sericin, ethanol was added to wastewater (i.e., a sericin aqueous solution) after the degumming process to remove nonprotein materials, affording a sericin precipitate. To prepare Lab sericin, nonprotein materials were removed from a silkworm cocoon and sericin was subsequently extracted from the cocoon. Lab sericin and Plant sericin exhibited similar solution viscosities, gel strengths, and crystallinity indices, indicative of the similar molecular weights (MWs) of the two sericin samples. In the case of sericin powder, Plant sericin was more crystalline than Lab sericin due to its treatment with ethanol. The findings of this study revealed that sericin recovered from industrial wastewater can be used equally as its MW is similar to that of sericin obtained through laboratory-scale extraction.

• Computers and Concrete
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• v.27 no.3
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• pp.283-295
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• 2021

Existing meso-scale models of concrete need to refine the mesh grids of aggregate and cement mortar, which may greatly reduce the computational efficiency. To overcome this problem, a novel meso-scale modeling strategy, which is based on rigid body spring method and Voronoi diagram, is proposed in this study to establish the meso-scale model of concrete. Firstly, establish numerical aggregate models according to user-defined programs. Circle aggregates are adopted due to their high efficiency in generation and packing process, and the grading of aggregate are determined according to the distribution curve proposed by Full and Thompson; Secondly, extract the centroids of aggregates, and then develop the Voronoi diagram in which aggregate centroids are defined as initial scatters; Finally, establish the rigid body spring model for concrete based on the Voronoi diagram. Aggregates are represented by rigid blocks, and assumed to be unbreakable. Cement mortar is concentrated into the interface between adjacent blocks and represented by two uniform springs. The number of grids is consistent with that of aggregates in specimens, and no mesh-refinement of aggregates and cement mortar is required. The accuracy and efficiency of the proposed modeling strategy are firstly identified by comparing the numerical results with the experimental ones, and then the applicability of the proposed strategy with different volume percentage occupied by aggregates is investigated.

• Advances in nano research
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• v.6 no.2
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• pp.147-162
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• 2018

A new nonlocal higher order shear deformation theory (HSDT) is developed for buckling properties of single graphene sheet. The proposed nonlocal HSDT contains a new displacement field which incorporates undetermined integral terms and contains only two variables. The length scale parameter is considered in the present formulation by employing the nonlocal differential constitutive relations of Eringen. Closed-form solutions for critical buckling forces of the graphene sheets are obtained. Nonlocal elasticity theories are used to bring out the small scale influence on the critical buckling force of graphene sheets. Influences of length scale parameter, length, thickness of the graphene sheets and shear deformation on the critical buckling force have been examined.

• Advances in materials Research
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• v.7 no.1
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• pp.1-16
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• 2018

Thermal bifurcation buckling behavior of fully clamped Euler-Bernoulli nanobeam built of a through thickness functionally graded material is explored for the first time in the present paper. The variation of material properties of the FG nanobeam are graded along the thickness by a power-law form. Temperature dependency of the material constituents is also taken into consideration. Eringen's nonlocal elasticity model is employed to define the small-scale effects and long-range connections between the particles. The stability equations of the thermally induced FG nanobeam are derived via the principal of the minimum total potential energy and solved analytically for clamped boundary conditions, which lead for more accurate results. Moreover, the obtained buckling loads of FG nanobeam are validated with those existing works. Parametric studies are performed to examine the influences of various parameters such as power-law exponent, small scale effects and beam thickness on the critical thermal buckling load of the temperature-dependent FG nanobeams.

• ETRI Journal
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• v.40 no.5
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• pp.582-591
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• 2018

In this paper, we present a performance analysis of large-scale multi-input multi-output (MIMO) systems for wireless backhaul networks. We focus on fully connected N nodes in a wireless meshed and multi-hop network topology. We also consider a large number of antennas at both the receiver and transmitter. We investigate the transmission schemes to support fully connected N nodes for half-duplex and full-duplex transmission, analyze the achievable ergodic sum rate among N nodes, and propose a closed-form expression of the achievable ergodic sum rate for each scheme. Furthermore, we present numerical evaluation results and compare the resuts with closed-form expressions.

• Geomechanics and Engineering
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• v.32 no.1
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• pp.21-34
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• 2023

In order to analyze the effect of the cyclic lateral loading on the response of a pile-soil system, a full-scale single steel pile was subjected to one-way cyclic loading. The test pile was driven into a bi-layered soil consisting of a normally consolidated saturated clay overlying a silty sandy layer, the site being submerged by water up to one meter above the mudline in order to reproduce the conditions of an offshore pile foundation. The aim of this paper is to present the main results of interpretation of the cyclic lateral tests in terms of pile deflections, bending moment, and cyclic P-Y curves. From these latter an absolute secant reaction modulus E_AS,N was derived and a simple calculation model of the test single pile is proposed based on this modulus. Two applications of the proposed model are carried out, one with a 2D finite element modelling, and the second with a load transfer curves-based method.

• Animal Bioscience
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• v.37 no.4_spc
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• pp.742-754
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• 2024

Asia is not only the primary region for global pig production but also the largest consumer of pork worldwide. Although the pig production in Asia has made great progress in the past, it still is confronted with numerous challenges. These challenges include: inadequate land and feed resources, a substantial number of small-scale pig farms, escalating pressure to ensure environmental conservation, control of devastating infectious diseases, as well as coping with high temperatures and high humidity. To solve these problems, important investments of human and financial capital are required to promote large-scale production systems, exploit alternative feed resources, implement precision feeding, and focus on preventive medicine and vaccines as alternatives to antibiotics, improve pig breeding, and increase manure recycling. Implementation of these techniques and management practices will facilitate development of more environmentally-friendly and economically sustainable pig production systems in Asia, ultimately providing consumers with healthy pork products around the world.

• Journal of Technologic Dentistry
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• v.18 no.1
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• pp.73-94
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• 1996

This study was aimed for evaluating the validity of relative-productivity index on the basis of working hour(RPHW index) designed by author as new productivity index and drawing up a plan of bettering productivity to cope with financial difficulty of dental laboratories. Fortyeight dental laboratories extracted by cluster-sampling method form all the dental laboratories in Seoul were subjected for this study. And in each of them, the term of establishment which was divied into three group as short-term, mid-term and long-term group, the scale of dental laboratory which as divided into two group by number of dental technician as small-scale group and large-scale group, the salary system which was composed of salary criteria, pay according to ablility criteria and collectiveagree, the salary level, simple labor productivity index(SLP index), relative-productivity index on the basis of worker number(ROWN) and relative-productivity index on the basis of working hour(RPWH index) were surveyed through the self-administractive questionaires. The results as follows : Most of dental laboratories(93.6%) were managed by non-professional managers. The establishment rate per year of dental laboratory was the increase. The mean number of employees of dental laboratories was $7.00{\pm}3.90$ person. The ratio of smallscale group(under the 5 employees) was 42.6% and as the term of establishment was shorter, the ratio of small-scale group was higher. The mean establishment area of dental laboratories was $24.49{\pm}10.97$ unit and the mean establishment area per head of dental laboratories was $4.05{\pm}3.90$ unit. The estabilshment area and area per head were not significantly associted with the term of establishment, but as the term of establishment was shorter, the estabkishment area per head was slightly wider. The establishment area per head in small-scale group was significantly wider than large-scale group(over the 6 emplayees) The salary criteria(54.4%), pay according to ability(79.2)m ability criteria(77.1%) and collectiveagree(79.2%) as salary systems were used in the most of all dnetal laboratoies. The all salary systems were not significantly associated with the term of establishment and the scale of dental laboratories. The monthly mean salary level of dental laboratoies was $125.64{\pm}31.06$ milion won. The monthly salary level was not significantly associated with the term of establishment and the scale of dental laboratores. But the monthly salary level in the short-term group and the small-scale group were slightly lower than others. The SLP index, the RPWN index and the RPWH index of dental laboratories were $132.16{\pm}48.41$, $382.41{\pm}128.76$ and $76.06{\pm}25.11$, respectively. The SLP, the RPWN and the RPWH of dental laboratories were not significantly associated with the term SLP, the RPWN and the RPWH of dental laboratories were significantly associated with the area of dental laboratory and the salary level. Except for only the association salary criteria among salary system with RPWH of dental laboratories, all other salary system were not associated with the SLP, the RPWN and the RPWH of dental laboratories.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.498-502
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• 2004

The current study was conducted to monitor the possibility of the gene transfer among soil bacteria, including the effect of drift due to rain and surface water, in relation to the release of genetically modified organisms into the environment. Four types of bacteria, each with a distinct antibiotic marker, kanamycin-resistant P. fluorescens, rifampicin-resistant P. putida, chloramphenicol-resistant B. subtilis, and spectinomycin-resistant B. subtilis, were plated using a small-scale soil-core device designed to track drifting microorganisms. After three weeks of culture in the device, no Pseudomonas colonies resistant to both kanamycin and rifampicin were found. Likewise, no Bacillus colonies resistant to both chloramphenicol and spectinomycin were found. The gene transfer from glyphosate-tolerant soybeans to soil bacteria, including Rhizobium spp. as a symbiotic bacteria, was examined by hybridization using the DNA extracted from soil taken from pots, in which glyphosate-tolerant soybeans had been growing for 6 months. The results showed that 35S, T-nos, and EPSPS were observed in the positive control, but not in the DNA extracted from the soilborne microorganisms. In addition, no transgenes, such as the 35S promoter, T-nos, and EPSPS introduced into the GMO soybeans were detected in soilborne bacteria, Rhizobium leguminosarum, thereby strongly rejecting the possibility of gene transfer from the GMO soybeans to the bacterium.