• Nuclear Engineering and Technology
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• v.52 no.3
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• pp.469-476
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• 2020

Research reactors in-core experimental facilities are designed to provide the highest steady state flux for user's irradiation requirements. However, fuel conversion from highly enriched uranium (HEU) to low enriched uranium (LEU) driven by the ongoing effort to diminish proliferation risk, will impact reactor physics parameters. Preserving the reactor capability to produce the needed flux to perform its intended research functions, determines the conversion feasibility. This study investigates the neutron flux in the central experimental facility of two material test reactors (MTR), the IAEA generic10 MW benchmark reactor and the 22 MW s Egyptian Test and Research Reactor (ETRR-2). A 3D full core model with three uranium enrichment of 93%, 45%, and 20% was constructed utilizing the OpenMC particle transport Monte Carlo code. Neutronics calculations were performed for fresh fuel, the beginning of life cycle (BOL) and end of life cycle (EOL) for each of the three enrichments for both the IAEA 10 MW generic reactor and core 1/98 of the ETRR-2 reactor. Criticality calculations of the effective multiplication factor (K_eff) were executed for each of the twelve cases; results show a reasonable agreement with published benchmark values for both reactors. The thermal, epithermal and fast neutron fluxes were tallied across the core, utilizing the mesh tally capability of the code and are presented here. The axial flux in the central experimental facility was tallied at 1 cm intervals, for each of the cases; results for IAEA 10 MW show a maximum reduction of 14.32% in the thermal flux of LEU to that of the HEU, at EOL. The reduction of the thermal flux for fresh fuel was between 5.81% and 9.62%, with an average drop of 8.1%. At the BOL the thermal flux showed a larger reduction range of 6.92%-13.58% with an average drop of 10.73%. Furthermore, the fission reaction rate was calculated, results showed an increase in the peak fission rate of the LEU case compared to the HEU case. Results for the ETRR-2 reactor show an average increase of 62.31% in the thermal flux of LEU to that of the HEU due to the effect of spectrum hardening. The fission rate density increased with enrichment, resulting in 34% maximum increase in the HEU case compared to the LEU case at the assemblies surrounding the flux trap.

• KSBB Journal
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• v.22 no.5
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• pp.362-365
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• 2007

Cyanobacteria have been identified as one of the most promising group producing novel biochemically active natural products. Cyanobacteria are a very old group of prokaryotic organisms that produce very diverse secondary metabolites, especially non-ribosomal peptide and polyketide structures. Large multienzyme complexes which are responsible for the non-ribosomal biosynthesis of peptides are modular for the addition of a single amino acid. An activation of amino acid substrates results in an amino adenylate occuring via an adenylation domain (A-domain). A-domains are responsible for the recognition of amino acids as substrates within NP synthesis. The A-domain contains ten conserved motifs, A1 to A10. In this study, ten conserved motifs from A1 to A10 were checked regarding their amino acid sequence of the NRPS-module of Microcystis aeruginosa PCC 7806. The part of the amino acid sequence chosen was that which contained as many conserved motives as possible, and then these amino sequence were compared between other cyanobacteria to design a new degenerate primer. A new degenerate primer (A3/A7 primer) was designed to detect any putative NP synthetase region in unkwon cyanobacteria by a reverse translation of the conserved amino acid sequence and a search for cyanobacterial DNA bank.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.2
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• pp.137-142
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• 2010

Although multi-model speech recognizer has been shown to be quite successful in noisy speech recognition, the results were based on general speech front-ends which do not take into account noise adaptation techniques. In this paper, for the accurate evaluation of the multi-model based speech recognizer, we adopted a quite noise-robust speech front-end, AFE, which was proposed by the ETSI for the noisy DSR environment. For the performance comparison, the MTR which is known to give good results in the DSR environment has been used. Also, we modified the structure of the multi-model based speech recognizer to improve the recognition performance. N reference HMMs which are most similar to the input noisy speech are used as the acoustic models for recognition to cope with the errors in the selection of the reference HMMs and the noise signal variability. In addition, multiple SNR levels are used to train each of the reference HMMs to improve the robustness of the acoustic models. From the experimental results on the Aurora 2 databases, we could see better recognition rates using the modified multi-model based speech recognizer compared with the previous method.

• KSBB Journal
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• v.23 no.5
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• pp.398-402
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• 2008

Cyanobacteria havebeen identified as one of the most promising group producing novel biochemically active natural products. Cyanobacteria are a very old group of prokaryotic organisms that produce very diverse secondary metabolites, especially non-ribosomal peptide and polyketide structures. Though many useful natural products have been identified in cyanobacterial biomass, cyanobacteria produce also extracellular proteins related with NRPS/PKS. Detection of unknown secondary metabolites in medium was carried in the present study by a screening of 98 cyanobacterial strains. A degenerated PCR technique as molecular approaches was used for general screening of NRPS/PKS gene in cyanobacteria. A putative PKS gene was detected by DKF/DKR primer in 38 strains (38.8%) and PCR amplicons resulted from a presence of NRPS gene were showed by MTF2/MTR2 primer in 30 strains (30.6%) and by A3/A7 primer in 26 strains (26.5%). HPLC analysis for a detection of natural products was performed in extracts from medium in which cyanobacteria containing putative PKS or NRPS were cultivated. CBT57, CBT62, CBT590 and CBT632 strains were screened for a production of extracellular natural products. 5 pure substances were detected from medium of these cyanobacteria.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.10
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• pp.59-66
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• 2011

In electric power system, the circuit breaker is not operated when the higher voltage then the rated TRV(transient Recovery Voltage) appeared in the circuit breaking, The TRV of a circuit breaker means the characteristics of reignition by the arc between two poles. and is decided by the value of connecting Impedance. In this paper we of carried out many kinds of experiments varying the types of bus, the types of installation, the length of installation between 22.9 [kV] level circuit breaker and MTR in general 154/22.9[kV] system, We also simulated the characteristics of TRV using EMTP-RV program. The suitability of TRV in assessed by Uc, RRRV(Rate of Rise of Recovery Voltage) which are defined by the international guide, IEC62271-100. The values of RRRV gained from the cable-made bus are 590[%] lesser than those from the NSPB-made bus respectively. So the triangled type is more rational in the aspect of TRV.

• Journal of Oral Medicine and Pain
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• v.35 no.3
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• pp.221-227
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• 2010

MyoFascial Pain Syndrome(MFPS) is defined as a regional pain syndrome characterized by muscle pain caused by myofascial trigger points (MTrPs). Myofascial pain is a common cause of persistent regional pain such as neck pain, shoulder pain, headaches, and orofacial pain. Clinicians who deal with orofacial pain must also understand the role of myofascial pain. This case report presents the treatment of botulinum toxin A for chronic myofascial pain.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.275-277
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• 2001

In this paper a preventative and diagnostic system for high and ultra high voltage electric power transmission apparatus is proposed to secure substation normal operation. The proposed system consists of monitoring sub-system and diagnostic sub-system, which are mainly for GIS and main transformer, and the system will be applied for newly established 765kV class substation in Korea. Some guideline for combination with substation control system are presented, and engineering solution as an improved substation automation system is also proposed.

• Molecules and Cells
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• v.40 no.9
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• pp.632-642
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• 2017

The DevSR (DosSR) two-component system, which is a major regulatory system involved in oxygen sensing in mycobacteria, plays an important role in hypoxic induction of many genes in mycobacteria. We demonstrated that overexpression of the kinase domain of Mycobacterium tuberculosis (Mtb) PknB inhibited transcriptional activity of the DevR response regulator in Mycobacterium smegmatis and that this inhibitory effect was exerted through phosphorylation of DevR on Thr180 within its DNA-binding domain. Moreover, the purified kinase domain of Mtb PknB significantly phosphorylated RegX3, NarL, KdpE, TrcR, DosR, and MtrA response regulators of Mtb that contain the Thr residues corresponding to Thr180 of DevR in their DNA-binding domains, implying that transcriptional activities of these response regulators might also be inhibited when the kinase domain of PknB is overexpressed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.6
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• pp.797-803
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• 2012

In this paper, for minimizing the real-time operating load losses of the power transformer, a SCADA optimum operating system was developed, and the economic analyses on the test operation were performed. Transformer loss DB which reflects the economic integration operation criteria was constructed by referring the transformer manufacturer's loss data(iron loss, copper loss). Based on the loss DB, each substation transformer real-time loss was calculated according to the size of the transformer loads, and if integration or separation transformer operating conditions minimizing the loss are met, then a window pops-up and the dispatcher performs the substation equipments operation according to the procedure provided by this system. With the existing SCADA main program, the relation database of the substation facilities and integration/separation operation algorithm were developed and applied to Auto MTR Processor and pconn Processor Task module. Seven stations test data for seven months were analyzed for the economic analyses, and the results showed that Cost-Benefit ratio was 2.64, and IRR(Internal Rate of Return), 36%, which asserted the economic justification of the proposed system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.12
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• pp.514-521
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• 2006

The existing ULTC operation control strategy based on the measured data deteriorates the voltage compensation capability making the efficient corresponding to the load variation difficult by following the fixed load center point voltage. Accordingly, this paper proposes a new on-line fuzzy ULTC controller based on the designed multiple load center points which can improve the voltage compensation capability of ULTC and minimize voltage deviation by moving in real-time the load center point according to the load variation to an adequate position among the multiple load center points designed using the clustering technique. The Max-Min distance technique is adopted as the clustering technique for the decision of multiple load points from measured MTr load current and PTr voltage, and the minimum distance classifier is adopted for the decision of fuzzy output membership function. To verify the effectiveness of the proposed strategy, Visual C++ MFC-based simulation environments is developed. Finally, the superiority the proposed strategy is proved by comparing the fuzzy ULTC operation control results based on multiple load center points with the existing ULTC operation control results based on fixed load center point using the data for three day.