• 한국통신학회논문지
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• 제41권6호
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• pp.698-706
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• 2016

기존 직교 주파수 분할 다중 방식 (orthogonal frequency division multiplexing; OFDM)에서는 최대전력 대 평균전력 비 (peak to average power ratio; PAPR)가 높아 회로 설계에 대한 어려움과, 신회 왜곡 등의 문제가 존재한다. 이에 따라 PAPR을 줄이기 위한 다양한 방법들이 제시되어 왔으나, 5G 이동통신에서 필요한 저지연을 만족하기 위해서는, OFDM의 직교성, 동기화가 지연시간 감소에 제한으로 작용한다. 비동기 방식에 알맞은 대안 중 하나는 GFDM이다. GFDM은 각 부 반송파가 주파수영역에서 나눠져 비동기 상황에서 강점을 가진다. 그러나 부심볼의 존재로 인해 OFDM보다 시간 축에서 신호의 중첩이 많기 때문에, 동일한 부 반송파 개수 조건에서 GFDM은 OFDM보다 높은 PAPR을 가진다. OFDM의 PAPR의 다양한 PAPR 감소기법 중 하나인 선택사상기법(selective mapping; SLM)을 GFDM에 적용하여, 시뮬레이션을 통해 기존 GFDM과 OFDM SLM 대비 GFDM SLM이 어느 정도 성능 향상이 있는지 확인하였다. 또 비동기 방식에서 간섭에 영향을 미치는 대역외 발사(out-of-band emission; OOB)를 비교하였다.

• 한국환경보건학회지
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• 제31권4호
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• pp.332-339
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• 2005

The environmental regulations in the world has been reinforced and many nations has devoted themselves to the development of cost-effective technology. Selective catalyst reduction(SCR) and selective non-catalyst reduction (SNCR) processes are mainly used to treat nitrogen oxidants generated from fossil-fuel combustion. One of these typical technologies for reduction of do-NOx is SNCR process has increased continuously because of the low cost for building and maintenance. Nevertheless the researches on the application to real scale plant by the reductant like Urea are rarely studied. In this paper, an experimental investigations were performed on the SNCR process in the industrial waste incineration plant. With no reducing agent, the concentration of NOx stayed in around 180 ppm $(O_2\;12\%)$ with the exhausting temperature of $950^{\circ}C$ and changed within the range of 20 ppm to remain relatively consistent. When $10\;wt\%)$ of a solution was added, the efficiency of denitrification reached above $61.4\%$ with the NSR of 2.0 and the exhausting temperature of $950^{\circ}C.$ When the concentration of the urea solution was set to $10\;wt\%$ and the sprinkling to four nozzles, the reaction temperature was reduced to about $50~100^{\circ}C$ with a mixture of $10\;wt\%\;CH_3OH\;and\;5wt\%\;Na_2CO_3$ in $40\;wt\%$ of the solution. The NOx removal efficiency increased to $78.4\%,$ achieving a broader and expansive range of reaction temperatures than the addition of an unmixed pure solution.

• Journal of Microbiology and Biotechnology
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• 제26권6호
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• pp.1046-1056
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• 2016

RV-23 is a melittin-related antibacterial peptide (MRP) with lower cytotoxicity than either melittin or AR-23, another MRP. The aim of this study was to explore the mechanism of RV-23's antibacterial selectivity and its hemocompatibility. The results showed that all the peptides exhibited lytic activity against Staphylococcus aureus and Escherichia coli, with RV-23 showing the highest potency. Moreover, RV-23 had lower cytotoxicity than melittin or AR-23 at their minimal inhibitory concentration. In addition, CD experiments showed that melittin, RV-23, and AR-23 all had a typical α-helical structure, and RV-23 had the lowest α-helix content. The structural information showed that RV-23 has the lowest hydrophobicity and highest hydrophobic moment. Because hydrophobicity and α-helix content are believed to correlate with hemolysis, the results indicate that the selective lytic activity against bacteria of RV-23 may be due to its low hydrophobicity and α-helicity, which lead to low cytotoxicity without affecting antibacterial activity. Furthermore, RV-23 did not affect the structure and function of blood components such as red blood cells, platelets, albumin, and the blood coagulation system. In conclusion, RV-23 is a cell-selective antibacterial peptide with high hemocompatibility due to its unique structure.

• 한국수산과학회지
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• 제56권2호
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• pp.212-220
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• 2023

Over the past 50 years, red sea bream Pagrus major has been selectively bred for more than 10 generations to improve its growth rate. However, the effect of genetic factors on growth under low- or non-fish meal diet is still unclear. Here, we analyzed 251 individuals randomly mating 21 females (dam) and 16 males (sire) to determine the difference in growth between non-fish meal (i.e., treatment group) and fish meal-based diet (i.e., control group), if any. The kinship coefficient between each group of individuals and their parents was estimated by the KING (Kinship-based Inference for GWASs) software package. The presumed parents of 74 individuals in the treatment group and 57 individuals in the control group could be effectively identified. Notably, one specific female was consistently related to high- rather than low-growth individuals in both groups. In addition, more than one parent in each group was related to either high- or low-growth individuals. Parents of both high-growth individuals in the treatment group and low-growth individuals in the control group were also identified. Although further study is required on various growth factors, this study suggests the possibility of selective breeding under non-fish meal diet.

• 대한의생명과학회지
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• 제23권2호
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• pp.64-72
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• 2017

The formation of brown colonies due to phenol oxidase activity on classic agar media containing natural material extracts of Helianthus annuus or on medium containing L-3,4-dihydroxyphenylalanine has been used to identify Cryptococcus species complex. In this study, various natural materials were used to develop a modified medium and to identify five major serotypes of Cryptococcus species complex. Serotypes A, D, and A/D were pigmented on medium using Perilla frutescens var. japonica Hara (PerJ agar) after a three-day incubation. Serotypes B and C were pigmented on PerJ agar after four- and five-day incubations, respectively. Growth time and pigmentation of the five serotypes occurred more rapidly on PerJ agar than on the other media. In addition, colony morphology, size, and pigmentation were specific by serotype. In conclusion, PerJ agar should be used in clinic settings to identify Cryptococcus species complex and its serotypes rapidly.

• ETRI Journal
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• 제37권1호
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• pp.32-42
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• 2015

Orthogonal frequency-division multiplexing (OFDM) suffers from spectral nulls of frequency-selective fading channels. Linear precoded (LP-) OFDM is an effective method that guarantees symbol detectability by spreading the frequency-domain symbols over the whole spectrum. This paper proposes a computationally efficient and low-cost implementation for discrete Hartley transform (DHT) precoded OFDM systems. Compared to conventional DHT-OFDM systems, at the transmitter, both the DHT and the inverse discrete Fourier transform are replaced by a one-level butterfly structure that involves only one addition per symbol to generate the time-domain DHT-OFDM signal. At the receiver, only the DHT is required to recover the distorted signal with a single-tap equalizer in contrast to both the DHT and the DFT in the conventional DHT-OFDM. Theoretical analysis of DHT-OFDM with linear equalizers is presented and confirmed by numerical simulation. It is shown that the proposed DHT-OFDM system achieves similar performance when compared to other LP-OFDMs but exhibits a lower implementation complexity and peak-to-average power ratio.

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.667-671
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• 2006

The new MPV-type reagents, B-acetoxydiisopinocampheylborane ($Ipc _2$BOAc) and B-trifluoroacetoxydiisopinocampheylborane $(Ipc _2BO _2CCF _3)$, have been prepared and their reducing characteristics in the reduction of carbonyl compound have been examined in order to find out a new reducing system with unique applicability in organic synthesis. In general, the reactivity of $Ipc _2BO _2CCF _3$ appears to be stronger than that of $Ipc _2$BOAc, presumably due to the acidity increase by the electron-withdrawing fluorine-substituent. Both reagents show an excellent selectivity in 1,2-reduction of $\alpha,\beta$-unsaturatedcarbonyl compounds and in competitive reduction between structurally different carbonyl compounds. In addition, $Ipc _2BO _2CCF _3$ shows interesting features in the stereoreduction of cyclic ketones.

• 센서학회지
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• 제21권6호
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• pp.402-407
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• 2012

We report a Fabry-Perot interferometer (FPI)-based multi-channel micro-spectrometer used for multi-gas measurement in the spectral range of $3-5{\mu}m$ and its gas sensing performance. The fabricated infrared (IR) spectrometer consists of two parts: an FPI on the top side for selective IR filtering and a $V_2O_5$-based IR detector array on the bottom side for the detection of the filtered IR. Experimental results show that the FPI-based multi-channel gas sensor has reliability and selectivity for simultaneously detecting environmentally harmful gases such as $CH_4$, $CO_2$, $N_2O$ and CO in the spectral range of $3-5{\mu}m$. The fabricated FPI-based multi-channel gas sensor also demonstrated that a reliable and selective detection of gas concentrations ranging from 0 to 500 ppm is feasible. In addition, the electrical characteristics demonstrate a superior response performance in regards to the selectivity in the multi-target gases.

• Childhood Kidney Diseases
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• 제19권2호
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• pp.65-70
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• 2015

It is well known that proteins present in the primary urine are reabsorbed in the renal proximal tubules, and that this reabsorption is mediated via the megalin-cubilin complex and the neonatal $Fc{\gamma}$ receptor. However, the reabsorption is also thought to be influenced by an electrostatic interaction between protein molecules and the microvilli of the renal proximal tubules. By analyzing the charge diversity of urinary IgG, we showed that this reabsorption process occurs in a cationic charge-preferential manner. The charge-selective molecular sieving function of the glomerular capillary walls has long been a target of research since Brenner et al. demonstrated the existence of this function by a differential clearance study by using the anionic dextran sulfate polymer. However, conclusive evidence was not obtained when the study was performed using differential clearance of serum proteins. We noted that immunoglobulin (Ig) A and IgG have similar molecular sizes but distinct molecular isoelectric points. Therefore, we studied the differential clearance of these serum proteins (clearance IgA/clearance IgG) in podocyte diseases and glomerulonephritis. In addition, we studied this differential clearance in patients with Dent disease rather than in normal subjects because the glomerular sieving function is considered to be normal in subjects with Dent disease. Our results clearly showed that the charge-selective barrier is operational in Dent disease, impaired in podocyte disease, and lacking in glomerulonephritis.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.2003-2007
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• 2011

We report a highly sensitive surface-enhanced Raman scattering (SERS) platform for the selective trace analysis of mercury (II) ions in drinkable water using aptamer-conjugated silver nanoparticles. Here, an aptamer designed to specifically bind to $Hg^{2+}$ ions in aqueous solution was labelled with a TAMRA moiety at the 5' end and used as a Raman reporter. Polyamine spermine tetrahydrochloride (spermine) was used to promote surface adsorption of the aptamer probes onto the silver nanoparticles. When $Hg^{2+}$ ions are added to the system, binding of $Hg^{2+}$ with T-T pairs results in a conformational rearrangement of the aptamer to form a hairpin structure. As a result of the reduced of electrostatic repulsion between silver nanoparticles, aggregation of silver nanoparticles occurs, and the SERS signal is significantly increased upon the addition of $Hg^{2+}$ ions. Under optimized assay conditions, the concentration limit of detection was estimated to be 5 nM, and this satisfies a limit of detection below the EPA defined limit of 10 nM in drinkable water.