• Korean Journal of Materials Research
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• v.34 no.3
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• pp.170-174
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• 2024

In this study, we report the microstructural evolution and shear strength of an Sn-Sb alloy, used for die attach process as a solder layer of backside metal (BSM). The Sb content in the binary system was less than 1 at%. A chip with the Sn-Sb BSM was attached to a Ag plated Cu lead frame. The microstructure evolution was investigated after die bonding at 330 ℃, die bonding and isothermal heat treatment at 330 ℃ for 5 min and wire bonding at 260 ℃, respectively. At the interface between the chip and lead frame, Ni₃Sn₄ and Ag₃Sn intermetallic compounds (IMCs) layers and pure Sn regions were confirmed after die bonding. When the isothermal heat treatment is conducted, pure Sn regions disappear at the interface because the Sn is consumed to form Ni₃Sn₄ and Ag₃Sn IMCs. After the wire bonding process, the interface is composed of Ni₃Sn₄, Ag₃Sn and (Ag,Cu)₃Sn IMCs. The Sn-Sb BSM had a high maximum shear strength of 78.2 MPa, which is higher than the required specification of 6.2 MPa. In addition, it showed good wetting flow.

• The Korean Journal of Applied Statistics
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• v.23 no.4
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• pp.767-776
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• 2010

Frontier (1976) suggested a criterion based on the expected length of ordered random intervals under the Broken-stick model (Barton and David, 1956) to determine the optimal number of principal components retained. It is considered to be one of the methods that provide the most consistent simulation results (Jackson, 1993). This study is aimed to propose a method using the distribution of ordered random intervals to evaluate the contribution of principal components. We also examine several types of Gini indices along with the corresponding Lorenz curves to visualize the overall equivalence of those contributions.

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.674-681
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• 1997

Ternary compound ceramics, (1-y-x) BaTiO$_3$-y SrTiO$_3$-x MgTiO$_3$(0.00 x 0.20), were fabricated by the conventional ceramic process. The structural and dielectric properties of specimens were investigated while varying the composition and sintering temperature(1,200~1,45$0^{\circ}C$) in order to obtain the optimum condition of capacitor. As is well known, Curie temperature(T$_{c}$) of high dielectric-based ceramic(BaTiO$_3$) was shifted and temperature of capacitance was decreased in according to increase of solid solution with (Sr, Mg)TiO$_3$. As a result, a suitable condition of compound rate for capacitor was obtained such as the BSM-11(0.8BaTiO$_3$-0.1SrTiO$_3$-0.1MgTiO$_3$), and sintering temperature was sintered at 1,25$0^{\circ}C$ for two hours. In this case, dielectric constant<1,300, dielectric loss(tan$\delta$)<0.03, and the variation rate of capacitance had less than 3% in the range -10~7$0^{\circ}C$.>.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.603-612
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• 2004

This study was carried out to investigate the replacing fish meal or soybean meal effect of with feather meal or Bacillus sp. inoculated feather meal in broiler diets on the performances and nutrient utilization. One hundred and eighty broilers were randomly allotted to six dietary treatments(1) control, basal diet; (2) BFMl00, Fish meal replacing at 100% level with bacillus sp. inoculated feather meal; (3) BSM20, Soybean meal replacing at 20% level with bacillus sp. inoculated feather meal; (4) BFMl00+BSM20, Fish meal and soybean meal replacing at 100% level and 20% level with bacillus sp. inoculated feather meal, respectively; (5) GFMl00, Fish meal replacing at 100% level with general feather meal; and (6) GSM20, Soybean meal replacing at 20% level with general feather meal) in a 5 week feeding trial. In overall period, body weight gain of control was the highest(1,623g) and those of BFM 100, BFM 100+ BSM 20 and GFM 100 were 1,572g, 1,564g, and 1,078g, respectively. And that of GFM 100(1,078.3g) was the lowest(p<0.05) among treatments. Digestibility of dry matter for BFM 100+BSM 20(81.46%) was higher(p<0.05) than that for other treatments, and that of crude protein was the lowest (p<0.05). Digestibilities of organic matter were significantly(p<0.05) improved when Bacillus sp. inoculated feather meal was replaced at 100% level with fish meal in the basal diet. Methane and hydrogen sulfide gases from the feces were significantly(p<0.05) decreased in chicks fed the control, BFM 100 and GFM 100 diets, when observed after 3 weeks of feeding trials. Feed costs of the control and BFM 100 were 417 and 384 won, respectively but that of BSM 20 was 558 won. Therefore, replacement of fish meal with Bacillus sp. inoculated feather meal in the diets for chicks could be useful for economic production.

• Microbiology and Biotechnology Letters
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• v.37 no.2
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• pp.176-182
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• 2009

Hydrogen producing bacterium, strain MeL 6-2 was isolated from the sludge of the factory areas in Anyang through the acclimation in basal salt medium (BSM) supplemented with 10 g/L of sucrose. Isolated strain MeL 6-2 was a facultative anaerobe which could grow in both aerobic and anaerobic environments. An aerobically grown pure culture isolated from enriched culture was analyzed by 16S rDNA sequencing and identified as Rhodopseudomonas sp. MeL 6-2. Effects of the concentrations of glucose and sucrose on the hydrogen production rate and the hydrogen production yield were investigated. When glucose in the range of 1~12 g/L was supplemented to the BSM, strain MeL 6-2 could grow without lag phase. An increased glucose concentration increased the specific hydrogen production rate linearly to $4.2\;mmol-H_2{\cdot}L^{-1}{\cdot}h^{-1}$ at 10 g/L, and $60\;mmol-H_2{\cdot}mg-DCW^{-1}{\cdot}h^{-1}$, but decreased slightly as the concentration increased to 12 g/L. The hydrogen production yield was maintained over a range from 2.6 to $3.1\;mol-H_2{\cdot}mol-glucose^{-1}$. When sucrose in the range of 1~12 g/L was supplemented to the BSM, strain MeL 6-2 could grow after ten hours. An increased sucrose concentration increased the specific hydrogen production rate and the hydrogen production yield to $163\;mmol-H_2{\cdot}mg-DCW^{-1}{\cdot}h^{-1}$ and to $4.5\;mol-H_2{\cdot}mol-sucrose^{-1}$, respectively.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.375-378
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• 2002

Hydrogen producing bacterium, strain Ye13-6 was isolated from the sludge of the factory areas in Gunpo through the acclimation in basal salt medium(BSM) supplemented with 10g/ ${\ell}$ of sucrose. Isolated strain Ye13-6 was a facultative anaerobe which could grow in both aerobic and anaerobic environments. Effects of the concentrations of glucose and sucrose on the hydrogen production rate and the hydrogen production yield were investigated. When glucose in the range of 1${\sim}$12g/ ${\ell}$ was supplemented to the BSM, strain Ye13-6 could grow without lag phase. An increased glucose concentration increased the specific hydrogen production rate linearly to 60mmol-$H_2$ ${\cdot}$ mg-$DCW^{-1}$ ${\cdot}$ $h^{-1}$. The hydrogen production yield was maintained over a range from 2.6 to 3.1mol-$H_2$ ${\cdot}$ mol-$glucose^{-1}$. When sucrose in the range of 1${\sim}$12g/ ${\ell}$ was supplemented to the BSM, strain Ye13-6 could grow after ten hours. An increased sucrose concentration increased the specific hydrogen production rate and the hydrogen production yield to 163mmol-$H_2$ ${\cdot}$ mg-$DCW^{-1}$ ${\cdot}$ $h^{-1}$ and to 4.5mol-$H_2$ ${\cdot}$ mol-$sucrose^{-1}$, respectively.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.205-213
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• 2005

This study was conducted to evaluate the response of the selected aquatic plants to sulfonylurea(SU)-herbicides, which have been used widely in rice-cultivating areas in Korea, and the possibility of using them as bio-indicator species for biodiversity conservation. The aquatic plants identified in Kangwon province where butachlor have been used extensively for many years were much more varied than those in Chonnam where SU-herbicides have been used extensively for many years. The growth responses of Monochoria korsakowii, Marsilea quadrifolia and Salvinia natans to sulfonylurea herbicides such as bensulfuron-methyl(BSM) and pyrazosulfuron-ethyl(PSE), were much more sensitive than those to butachlor and molinate. The $GR_{50}$ values of BSM and PSE for M. korsakowii, M. quadrifolia and S. natans were relatively very low when compared with those of butachlor and molinate. The number of internode and dry weight of M. quadrifolia which was exposed to herbicides runoff from rice fields were seriously affected. The acetolactate synthase(ALS) activities of M. quadrifolia sensitively inhibited by BSM and PSE were, and $I_{50}$(Inhibition 50%) were 5.6 and 2.1 nM, respectively.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1270-1279
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• 2011

Bealmijang is a short-term aged paste made from meju, which is a brick of fermented soybeans and other ingredients. Different types of bealmijang are available depending on the geographic region or ingredients used. However, no study has clarified the microbial diversity of these types. We identified 17 and 14 fungal species from black soybean meju (BSM) and buckwheat meju (BWM), respectively, on the basis of morphology, culture characteristics, and internal transcribed spacer and ${\beta}$-tubulin gene sequencing. In both meju, Aspergillus oryzae, Rhizopus oryzae, Penicillium polonicum, P. steckii, Cladosporium tenuissimum, C. cladosporioides, C. uredinicola, and yeast species Pichia burtonii were commonly found. Moreover, A. flavus, A. niger, P. crustosum, P. citrinum, Eurotium niveoglaucum, Absidia corymbifera, Setomelanomma holmii, Cladosporium spp. and unclassified species were identified from BSM. A. clavatus, Mucor circinelloides, M. racemosus, P. brevicompactum, Davidiella tassiana, and Cladosporium spp. were isolated from BWM. Fast growing Zygomycetous fungi is considered important for the early stage of meju fermentation, and A. oryae and A. niger might play a pivotal role in meju fermentation owing to their excellent enzyme productive activities. It is supposed that Penicillium sp. and Pichia burtonii could contribute to the flavor of the final food products. Identification of this fungal diversity will be useful for understanding the microbiota that participate in meju fermentation, and these fungal isolates can be utilized in the fermented foods and biotechnology industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.125-132
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• 2017

Vehicular safety service reduces traffic accidents and traffic congestion by informing drivers in advance of threats that may occur while driving using vehicle-to-vehicle (V2V) communications in a wireless environment. For vehicle safety services, every vehicle must broadcasts a Basic Safety Message(BSM) periodically. In congested traffic areas, however, network congestion can easily happen, reduce the message delivery ratio, increase end-to-end delay and destabilize vehicular safety service system. In this paper, to solve the network congestion problem in vehicle safety communications, we approximate the relationship between channel busy ratio and the number of vehicles and use it to estimate the total network congestion. We propose a new context-aware transmit power control algorithm which controls the transmission power based on total network congestion. The performance of the proposed algorithm is evaluated using Qualnet, a network simulator. As a result, the estimation of total network congestion is accurately approximated except in specific scenarios, and the packet error rate in vehicle safety communication is reduced through transmit power control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.2
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• pp.133-141
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• 2014

Recently, various services are provided by using WAVE protocol for communication among neighboring vehicles. And in order to operate stable system, the gateway for interconnecting in and out vehicle networks is required. In this paper, we propose gateway interconnecting WAVE and CAN protocol. The proposed gateway based on OSEK OS consists of a communication layer, a message translator layer and a message management layer. In the communication layer, WAVE communication part and CAN communication part are designed to communicate with WAVE and CAN. And in the message management layer, message management layer functions to store the received messages and check errors with the message. Based on these functions, experiment was conducted to analyze performance of the gateway with two scenarios such as transmitting periodically BSM as a message structure for safety services in vehicle-to-vehicle communications and responding to road side equipments requiring in-vehicle information. As a result of test, we verify our gateway performance by analyzing measured time in test scenarios.