• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1638-1641
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• 2008

We have investigated the effectiveness of a gravure printing method for the fabrication of organic light-emitting diode (OLED) and Organic Thin Film Transistor (OTFT). Printing of the organic layers was performed with a small-scale gravure coating machine, while the metallic layers were vacuum-evaporated. Devices with gravure-printed layers are at least comparable with the spin-coated devices. Effects of the solvent formulation and surface energy mismatch between the organic layer materials on the printed patterns and device performance were discussed. We will present the initial design and experimental data of OTFT fabricated by roll-type soft contact transfer process.

• 천문학회지
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• 제33권1호
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• pp.47-55
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• 2000

Nonpotential characteristics of magnetic fields in AR 5747 are examined using Mees Solar Observatory magnetograms taken on Oct. 20, 1989 to Oct. 22, 1989. The active region showed such violent flaring activities during the observational span that strong X-ray flares took place including a 2B/X3 flare. The magnetogram data were obtained by the Haleakala Stokes Polarimeter which provides simultaneous Stokes profiles of the Fe I doublet 6301.5 and 6302.5. A nonlinear least square method was adopted to derive the magnetic field vectors from the observed Stokes profiles and a multi-step ambiguity solution method was employed to resolve the $180^{\circ}$ ambiguity. From the ambiguity-resolved vector magnetograms, we have derived a set of physical quantities characterizing the field configuration, which are magnetic flux, vertical current density, magnetic shear angle, angular shear, magnetic free energy density, a measure of magnetic field discontinuity MAD and linear force-free coefficient. Our results show that (1) magnetic nonpotentiality is concentrated near the inversion line in the flaring sites, (2) all the physical parameters decreased with time, which may imply that the active region was in a relaxation stage of its evolution, (3) 2-D MAD has similar patterns with other nonpotential parameters, demonstrating that it can be utilized as an useful parameter of flare producing active region, and (4) the linear force-free coefficient could be a evolutionary indicator with a merit as a global nonpotential parameter.

• 대한의생명과학회지
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• 제13권4호
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• pp.361-368
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• 2007

Biological samples can be fixed either by chemical method by using chemical solution or physical methods by using heat treatment. The problem in traditional heat fixation is unsatisfactory quality due to uneven heat conduction in specimen and loss of inner cell contents. Chemical fixation method also bears several intrinsic problems like the limit in specimen size, time consumption in fixative impregnation, and loss of low molecular weight cell components. These factors deteriorate the quality of fixed specimen, thus limit the magnification and contrast of tissue pictures. Microwave heat has been reported to be a good alternative to current chemical methods to overcome these problem. In this study, we tried to introduce the microwave energy method to routine fixation work in hospital. We replaced chemical fixative with saline to provide moderate reaction condition, and used frozen section to reduce time for sample preparation. Temperature was measured at each experiment. The fixation of rat kidney tissue with 2.45 GHz electromagnetic wave and saline showed similar result to the control group fixed with traditional chemical method. Human tumor tissue fixed with 2.45 GHz electromagnetic in frozen section was improved in terms of histochemistry of PAS and immunohistochemistry of tumor marker like cytokeratin. Total turnaround time was reduced from $24\sim38$ h to to $2\sim4$ h. In conclusion, the quality of samples prepared by microwave heating method was at least as good as that of traditional method. If the condition for the fixation of different specimens is standardized, this new method could be applied to routine work in hospital, and could save working time as well.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.153-153
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• 2008

Practical application of single-walled carbon nanotubes (SWCNTs) qualified as a promising material has been limited by either poor dispersion or their insolubility in aqueous or organic media due to formation of bundling by relatively high surface energy. Thus, major attention to overcome this issue has been paid at surface modification of CNTs by functionalization, but this introduces defects to the sidewall of CNTs, consequently perturbing the inherent electronic and optical properties. Therefore, using surfactants is a general approach to disperse SWCNTs with lower damages by which bundled nanotubes could be dispersed up to the level of individuals or small bundles. Here, we have investigated various surfactants for their efficiency in dissolving purified SWCNTs produced by arc discharge in deionized water. To compare the surfactants respectively, we have determined the least amount of each surfactant to suspend the nanotubes under optimized experimental conditions(CNT amount, sonication power, and centrifugation speed, etc.) set on the basis of the most common surfactant (sodium dodecyl sulfate, SDS) and discussed the qualitative and quantitative characterization of SWCNT dispersions by UV-Vis absorption spectroscopy. Quantitative aspect about nanotube dispersion was that in particular N-methyl-2-pyrrolidone (NMP) and sodium dodecylbenzene sulfonate (NaDDBS) were found to be effective in dispersing individual tubes.

• 대한건축학회논문집:구조계
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• 제34권12호
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• pp.11-20
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• 2018

The purpose of this study is to investigate the seismic performance of exposed column-base plate strong-axis connections for small-sized steel buildings. Even though the seismic design for small-sized buildings became mandatory since Dec.2017, the arbitrary connection details in steel structure have been applied at the construction site, which is considered to be very insufficient to secure structural safety and stability considering the increased seismic risk. Therefore, a series of experimental test programs had been carried out to develop enhanced connection details in order to ensue the adequate seismic safety of small buildings. The hysteretic behavior of the exposed column-base plate connections commonly used in Korea seem to be very pure poor due to the "Rocking" phenomena between anchor plate and concrete by the residual plastic deformation of anchor bolts. A series of hysteretic tests were conducted to find the solution to overcome the "Rocking" phenomena of the exposed column-base plate connections, finally the stable seismic behavior was obtained by uisng at least 8 anchor bolts with good bonding strength to the protptype specimen.

• Smart Structures and Systems
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• 제29권1호
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• pp.105-116
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• 2022

Stay cables play an essential role in cable-stayed bridges. Severe vibrations and/or harsh environment may result in cable failures. Therefore, an efficient structural health monitoring (SHM) solution for cable damage detection is necessary. This study proposes a data-driven method for immediately detecting cable damage from measured cable forces by recognizing pattern transition from the intact condition when damage occurs. In the proposed method, pattern recognition for cable damage detection is realized by time series classification (TSC) using a deep learning (DL) model, namely, the long short term memory fully convolutional network (LSTM-FCN). First, a TSC classifier is trained and validated using the cable forces (or cable force ratios) collected from intact stay cables, setting the segmented data series as input and the cable (or cable pair) ID as class labels. Subsequently, the classifier is tested using the data collected under possible damaged conditions. Finally, the cable or cable pair corresponding to the least classification accuracy is recommended as the most probable damaged cable or cable pair. A case study using measured cable forces from an in-service cable-stayed bridge shows that the cable with damage can be correctly identified using the proposed DL-TSC method. Compared with existing cable damage detection methods in the literature, the DL-TSC method requires minor data preprocessing and feature engineering and thus enables fast and convenient early detection in real applications.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2648-2665
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• 2022

Device-to-device (D2D) multicast has become a promising technology to provide specific services within a small geographical region with a high data rate, low delay and low energy consumption. However, D2D multicast communications are allowed to reuse the same channels with cellular uplinks and result in mutual interference in a cell. In this paper, an intelligent channel assignment algorithm is designed in D2D underlaid cellular networks with the target of maximizing network throughput. We first model the channel assignment problem to be a throughput maximizing problem which is NP-hard. To solve the problem in a feasible way, a novel channel assignment algorithm is proposed. The key idea is to find the appropriate cellular communications and D2D multicast groups to share a channel without causing critical interference, i.e., finding a channel for a D2D multicast group which generates the least interference to network based on current channel assignment status. In order to show the efficacy and effectiveness of our proposed algorithm, a novel search algorithm is proposed to find the near-optimal solution as the baseline for comparisons. Simulation results show that the proposed algorithm improves the network throughput.

• Journal of Radiation Protection and Research
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• 제21권1호
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• pp.51-58
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• 1996

2년간의 온실실험을 통하여 벼, 콩, 배추, 무의 생육초기와 생육후기에 $^{54}Mn,\;^{60}Co,\;^{85}Sr,\;^{137}Cs$의 혼합용액을 산성 양질사토로 상층부를 채운 재배상자내 담수 또는 토양의 표면에 가하고 작물수확 직후에 지하 $15{\sim}20cm$까지 토양길이에 따른 방사성 핵종의 농도분포를 조사하였다. 방사성 핵종의 농도는 토양깊이에 따라 지수함수적으로 감소하는 경향으로 처리한 방사능의 80%이상이 지하 $3{\sim}4cm$ 이내 에 분포하였다. 핵종간 지하로의 이동성은 대체로 $^{85}Sr>^{54}Mn>^{60}Co{\geq}^{137}Cs$의 순이었다. 재배작물간에 이동 정도는 벼 재배토양에서 가장 높았고 N, P, K의 시비량이 가장 적었던 콩 재배토양에서 가장 낮았다. 두 처리시기간 지하분포 양상의 차이는 침적후 시간경과에 따라 단위시간당 지하 1cm 밑으로 이동하는 방사능량이 감소한다는 것을 나타내었다. 작물의 생육 초기에 방사성 핵종을 가한 후 실시된 염화칼리와 석회의 동시첨가로 핵종의 지하이동은 밭작물에서는 변화가 없거나 다소 억제되었으나 벼에서는 약간 촉진되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권1호
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• pp.130-136
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• 2011

Methane is known to be one of the major greenhouse gases. On a global scale, livestock farming may contribute 18% of total greenhouse gas emissions. Though methane contribution is less than 2% of all the factors leading to global warming, it plays an important role because it is 21 times more effective than carbon dioxide. Methane emission is a direct result of the fermentation process performed by ruminal microorganisms and, in particular, the archael methanogens. Reducing methane emission would benefit both ruminant production and the environment. Methane generation can be reduced by electron-sink metabolic pathways to dispose of the reducing moieties. An alternative way for methane control in the rumen is to apply inhibitors against methanogens. Generating methane from manure has considerable merit because it appears to offer at least a partial solution to two pressing problems-environmental crisis and energy shortage. An obvious benefit from methane production is the energy value of the gas itself. Control of methane emission by rumen microbes in Korea has mainly been focused on application of various chemicals, such as BES and PMDI, that inhibit the growth and activity of methanogens in the rumen. Alternatives were to apply long-chain polyunsaturated fatty acids and oils with or without organic acids (malate and fumarate). The results for trials with methane reducing agents and the situation of biogas production industries and a typical biogas plant in Korea will be introduced here.

• 한국임상수의학회지
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• 제15권1호
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• pp.62-74
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• 1998

In feedlot cattle the abrupt change of diet from roughage to a large quantity of grain for the purpose to improve production often results in increased occurrence of rumen acidosis or acute carbohydrate encouragement enterotoxemia, bloats diarrhea liver abscess and laminitis or robot disease. The common management practice to control these problem is to increase the amount of concentrates in the diet in a stepwise manner until the animals are adapted to a high-grain ration. However this practice requires at least about 3 weeks adaptation period and specially prepared adaptation rations which contain various amount of concentrates. Present experiment was undertaken in order to findout the more simple and rapid adaptation method of cattle to a high grain ration. Nineteen Korean calves aging from four to six month were fed artifical hay (Youngchoun Chuk-Hyup, Korea) which contains 10% of concentrates or alfalfa and rye grass hays for two months and randomly alloted to three experimental groups and two control groups. The experimental group-1 was inoculated by stomach tube for two days with li500 ml/day of ruminal fluid fished from Korean beef cattle that had been previously adapted to a high-energy ration. The experimental group-2 was inoculated by trocalization for two days with the same ruminal fluid. The experimental group-3 was inoculated by trocalization with 1,500 ml/day of bacterial culture which contained 2$\times $10$^{9}$/m1 of Gram-negative bacteria derived from adapted luminal fluid. The two control groups were treated with normal saline solution by the same methods. All animals were fed high-energy ration that contained 80% of grain ad libitum for 30-74 days beginning on the third of the treatment. The effect of the inoculation on the adaptation was observed clinicopathologically with the following results; All of the experimental calves inoculated with the ruminal fluid or Gram-negative bacterial culture derived from adapted cattle did not show any signs of rumen acidosis or other related diseases, while most of the control calves did show diarrhea and bloat and a calf laminitis. The average daily weight gain and feed efficiency of experimental calves were slightly improved compared with control calves. Following the feeding of high-grain rational the pH of the ruminal fluid was lowered in both the experimental and control groups. However severe acidosis with the pH of below 5.0 was observed in only a control group-2. The protozoal number in ruminal fluid was markedly decreased during the high-grain feeding in both the experimental and control calves. However the decrease was mere severe in control calves compared with the experimental calves. The activation of the protozoa were completely disappeared within nine hours at the refrigerator temperature (4"C). No significant differences in heamatological and blood chemical values between the experimental and control calves were recognized. However in one control calf which showed clinically laminitis marked elevations of serum glutamic oxaloacetate transaminase and lactic dehydrogenase activities and a decrease of serum glucose level were observed. From these results it would be concluded the intraruminal transplantation of unadapted calves with the adapted ruminal fluid from cattle previously adapted to a high-energy ration prevents disease problem associated with high-grain feeding and improve weight gain and feed efficiency.ency.