• Molecules and Cells
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• 제28권6호
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• pp.515-520
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• 2009

Applications of bone marrow-derived mesenchymal stem cells in gene therapy have been hampered by the low efficiency of gene transfer to these cells. In current transduction protocols, retrovirus particles with foreign genes make only limited contact with their target cells by passive diffusion and have short life spans, thereby limiting the chances of viral infection. We theorized that mechanically agitating the virus-containing cell suspensions would increase the movement of viruses and target cells, resulting in increase of contact between them. Application of our mechanical agitation for transduction process has increased the absorption of retrovirus particles more than five times compared to the previous static method without changing cell growth rate and viability. The addition of a mechanical agitation step increased transduction efficiency to 42%, higher than that of any other previously-known static transduction protocol.

• 한국물환경학회지
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• 제22권5호
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• pp.824-830
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• 2006

Several tests were conducted to optimize the design parameters of ln-situ soil flushing processes for diesel contaminated soil. According to the batch extraction test for three anionic surfactants evaluation, Calgonit limiting bubble occurrence was selected for its higher oil cleaning efficiency. After optimum surfactant selection, there were many sets of column flushing test. Over 70% of BTEX was removed in this surfactant dose with 400% of soil volume. In the case of no surfactant addition flushing in column, so called "blank flushing test", BTEX removal rate was 64%. But when we reused the effluent for the cleaning solution, the removal rate was decreased to 46.9%. This result showed reabsorption of oil occurred on the soil. With the addition of Calgonit solution to the diesel contaminated column, BTEX was removed up to 98.9% during the first flushing and 99.4% for the second recirculation flushing. In microcosm tests, diesel contaminated soils were cleaned by both surfactant flushing and biological activities. In anoxic condition, nitrate was used as an electron acceptor while the surfactant and the oil were used an electron donor. BTEX removal efficiency could be achieved up to 80% by biological degradation.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권1호
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• pp.1-14
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• 2024

Time-series forecasting is extensively used in the actual world. Recent research has shown that Transformers with a self-attention mechanism at their core exhibit better performance when dealing with such problems. However, most of the existing Transformer models used for time series prediction use the traditional encoder-decoder architecture, which is complex and leads to low model processing efficiency, thus limiting the ability to mine deep time dependencies by increasing model depth. Secondly, the secondary computational complexity of the self-attention mechanism also increases computational overhead and reduces processing efficiency. To address these issues, the paper designs an efficient multi-layer attention-based time-series forecasting model. This model has the following characteristics: (i) It abandons the traditional encoder-decoder based Transformer architecture and constructs a time series prediction model based on multi-layer attention mechanism, improving the model's ability to mine deep time dependencies. (ii) A cross attention module based on cross attention mechanism was designed to enhance information exchange between historical and predictive sequences. (iii) Applying a recently proposed sparse attention mechanism to our model reduces computational overhead and improves processing efficiency. Experiments on multiple datasets have shown that our model can significantly increase the performance of current advanced Transformer methods in time series forecasting, including LogTrans, Reformer, and Informer.

• Current Photovoltaic Research
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• 제12권1호
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• pp.6-16
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• 2024

The efficiency of silicon solar cells is approaching a theoretical limit referred to as 'the state of the art'. Consequently, maintaining efficiency is more productive than pursuing improvements the last room for limiting efficiency. One of the primary considerations in silicon module conservation is the occurrence of failures and degradation. Degradation can be mitigated during the cell manufacturing stage, unlike physical and spontaneous failure. It is mostly because the chemical reaction is triggered by the carrier generation of thermal and light injection, an inherent aspect of the solar cell environment. Therefore, numerous researchers and cell manufacturers are engaged in implementing mitigation strategies based on the physical degradation mechanism.

• Asian-Australasian Journal of Animal Sciences
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• 제24권10호
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• pp.1417-1424
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• 2011

This study was conducted to assess the relation between threonine (Thr) oxidation rate and threonine efficiency on rat and chicken fed with graded levels of protein and threonine. The increase in threonine content from 0.28 to 0.72% in a diet containing 12.0% crude protein (CP) caused a gradual increase in threonine dehydrogenase (TDG) activity in rat liver. Similar, but more pronounced results were observed after 18.0% CP in the diet. Both protein levels in combination with the highest level of threonine supplementation increased liver TDG activity significantly, indicating enhanced threonine catabolism. Parameters of efficiency of threonine utilization calculated from parallel nitrogen balance studies decreased significantly and indicated threonine oversupply after a maximum of threonine supplementation. At the lower levels of threonine addition the efficiency of threonine utilization was not significantly changed. In the chicken liver up to 0.60% true digestible threonine (dThr) in the 18.5% CP diet produced no effect on the TDG activity. However, TDG activity in the liver was elevated by the diet containing 22.5% CP (0.60% dThr) and the efficiency of threonine utilization decreased, indicating the end of threonine limiting range. In conclusion, the in vitro TDG activity in the liver of rat and growing chicken has an indicator function for the dietary supply of threonine.

• 한국환경과학회지
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• 제15권3호
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• pp.211-219
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• 2006

An experimental study on the removal of VOCs gas using a biomembrane reactor were carried out at various inlet gas concentration, specific loading rate, retention time and gas flow rate of volume. The variations of efficiency and various parameters, which are relevant to gas removal, with mixing of soluble gas and without have been discussed. More than 95% of the toluene and methanol present in the feed was successfully removed in each study. The elimination of methanol with mixture of soluble compound of about 300 mg/h corresponds to a portion of 21% if there is a feed stream of 1400 mg/h. On the contrary the maximum efficiency of about 72% of toluene was reached. This is to be rated as a treatment of sorption that the limiting factor of the dismantling speed could be represented by this difficult degradable component. Nevertheless the elimination capacities for this reactor for toluene were on a very high level. For substances which show a very high solubility in silicon rubber an advantage of a bio membrane is clearly shown. Therefore a similarly good result is expected for n-hexane, because of its relatively good permeability which was distinguished during permeation experiments.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.205-208
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• 2004

Tile pilot scale biopile system was designed and constructed for evaluation of biopile efficiency. For the biopile system construction, two soil samples that were contaminated by mainly diesel were selected. The pilot scale biopile were consisted of the biopile dome, aeration system and monitoring system and two biopiles(pile A and pile B) were operated with nutrients and inoculum for more 100 days. The initial TPH concentrations for pile A and pile B were about 10,000 mg/kg and 2,300 mg/kg, respectively. After 70 days, the microbial densities in the pile A was increased and in the pile B it was no changed. The TPH contents decreased about 70% in the pile A and 30% in the pile B. Also, various kinds of PAHs were detected by analyzing the GC/MSD, and the reducing ratio in the piles A and pile B were similarly declined. The average biodegradation rates were calculated about 66.8mg/kg-day in the pile A and 10.9mg/kg-day in the pile B. During the operation period, pile temperature was the major limiting condition for the efficiency of all biopiles.

• 한국물환경학회지
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• 제26권5호
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• pp.810-815
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• 2010

Ultrasonic sludge pre-treatment has been studied to enhance the performance of anaerobic digestion by increasing sludge hydrolysis which is regarded as the rate-limiting-step of anaerobic digestion. In this study, the effect of ultrasonic pre-treatment on sludge hydrolysis (solubilization) and methane production was investigated. Sludge solubilization efficiency increased with ultrasonic energy input. However, it is uneconomical to apply more than 720 kJ/L as the solubilization efficiency per energy input declines afterwards. Volatile fatty acids concentration increased after the ultrasonic sludge hydrolysis. Anaerobic batch digestion showed that methane volume reached 64.7 and 84.5 mL after 18 days of incubation with the control sludge and ultrasonically hydrolyzed sludge, respectively. Methane production potential, maximum methane production rate, and the lag time of modified Gompertz equation were changed from 70 mL, 6.4 mL/day, and 1.2 days to 89 mL, 9.6 mL/day, and 0.5 day, respectively, after the ultrasonic sludge treatment. The results proved that ultrasonic pre-treatment contributed significantly not only for the methane production but also for the reduction of anaerobic digestion time which is critical for the performance of anaerobic sludge digestion.

• 한국전기전자재료학회논문지
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• 제25권5호
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• pp.345-348
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• 2012

The optical losses associated with the reflectance of incident radiation are among the most important factors limiting the efficiency of a solar cell. Therefore, photovoltaic cells normally require special surface structures or materials, which can reduce reflectance. In this study, nano-scale textured structures with anti-reflection properties were successfully formed on silicon. The surface of sicon wafer was etched by the inductively coupled plasma process using the gaseous mixture of $SF_6+O_2$. We demonstrate that the reflection characteristic has significantly reduced by ~0% compared with the flat surface. As a result, the power efficiency $P_{max}$ of the nano-scale textured silicon solar cell were enhanced up to 20%, which can be ascribed primarily to the improved light trapping in the proposed nano-scale texturing.

• Membrane and Water Treatment
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• 제7권4호
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• pp.341-353
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• 2016

Papermaking reconstituted tobacco is an important strategy for recycling the waste tobacco residues. To indentify the influences of the inorganic components on harmful components delivery in cigarette smoke, a self-made electrodialysis stack was assembled to desalt the tobacco extract. The influences of the applied current and extract content on the removal rate of the inorganic ions were investigated. Results indicated that the applied current was a dominant impact on the desalination performance. High currents lower than the limiting current density could accelerate the desalting efficiency but cause higher energy consumption. A current of 2 A, or current density of ${\sim}11mA{\cdot}cm^{-2}$, was an optimal choice by considering both the energy consumption and desalting efficiency. A 20% tobacco extract was an appropriate content for the electrodialysis process. More than 90% of inorganic ions could be removed under the optimum condition. The preliminary result indicated that removal of inorganic components was beneficial to decrease the harmful component delivery in cigarette smoke. Naturally, ED is an environmentally friendly and high-effective technology for desalting the tobacco extract.