• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.141-146
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• 2012

The rail surface defects which are generated on repeated rolling contact fatigue are getting increased according to high speed, high density, and minimum weight. In addition, Increasing noise and vibration are affected by these also impact load generated as well. Because of this phenomenon, more serious and critical damages were occurred. In fact, in order to control them, the rail grinding amount in Korea. This study evaluated how depth of hardening on rail surface is formed and suggested optimal rail grinding amount by RCF(rolling contact fatigue) test with generated contact pressure between KTX wheel and UIC60 rail by applying FEM analysis. Therefore, the amount was generated approximately 0.2mm/20MGT to maintain integrity of rail surface by getting rid of depth of hardening on rail according to rail accumulated passing tonnage.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.5
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• pp.60-69
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• 2013

An optimum configuration of the hybrid/dual swirl jet combustor for a micro-gas turbine was investigated experimentally. Location of pilot nozzle, angle and direction of swirler vane were varied systematically as main parameters under the conditions of constant thermal load. The results showed that the variation in locations of inner fuel nozzle and pilot burner resulted in significant change in flame shape and swirl intensity due to the changes in recirculating flow pattern and minimum flow area near burner exit, in particular, with the significant reduction of CO emission near lean-flammability limit. In addition, it was observed that the co-swirl configuration produced less CO and NOx emissions compared to the counter-swirl configuration.

• The Journal of Advanced Prosthodontics
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• v.8 no.1
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• pp.62-69
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• 2016

PURPOSE. The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. MATERIALS AND METHODS. Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. RESULTS. The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). CONCLUSION. Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.151-160
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• 2019

EPC companies to continue operating overseas, it is increasingly becoming apparent that risk is no longer something to be avoided but a subject to be managed. During the bidding stage, the requirements, specifications and project line items within the bid package must be studied in details to analyze the various risk factors in order to avoid cost overruns. However, reviewing vast quantities of bidding documents is time consuming and labor intensive and is not an easy task and this is where automated information technology can help. For this study, I have constructed an ITB analysis model based on Watson AI that can analyze and apply vast amount of documents more effectively in a short time. Configuration of the Watson Explorer AI architecture for AI-based ITB risk management model research, the selection of learning procedures and analysis subjects, and the performance evaluation criteria were defined, and a test bed was constructed to conduct a pilot research. Consequently, I verified the effectiveness of the analytical time reduction and the quality of its results and VOC operations by professionals.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.23-23
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• 2023

The Hairy labrador tea (Ledum palustre L. var. diversipilosum Nakai) is a evergreen small shrub, belonging to the Ericaceae and mainly distributed along the alpine areas of Hamgyeong-do in North Korea. Through seed physiological research on North Korean plants, we intend to obtain basic data for the development of mass propagation methods and use them for vegetation restoration. The internal and external morphological characters of the seed were observed using scanning electron microscopy or stereoscopy, and full seeds were selected through X-ray test. Seeds were cultured on a growth condition at 15/6℃ and 25/15℃ to examine the germination response according to temperature, and the number of germinated individuals was examined every 24 hours to calculate germination percentage and mean germination time. Low-temperature treatment (4℃) and hormone treatment (GA3) were performed to investigate the effect of dormancy breaking, and analysis of variance (ANOVA) was performed on the experimental results using SAS 9.4. The seeds of the Hairy labrador tea were elliptical-narrow in shape, and the epidermal cell wall pattern was reticulated. The final germination rate (FGP) was the highest at 58.9% under the condition of low temperature treatment at 25/15℃. The average number of days to germination (MGT) was the highest at 25.1 days without treatment at 15/6℃, and the average of the last germination days was confirmed to be about 13 days. As a result of low temperature treatment, it was confirmed that the final germination rate (FGP) increased by 43.3%. The significance of the final germination rate (FGP) was verified according to the pretreatment at 25/15℃.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.24-24
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• 2023

본 실험은 한반도 극지 고산식물인 진퍼리꽃나무[Chamaedaphne calyculata (L.) Moench] 종자의 형태적 특성을 조사하고 변온조건과 저온처리 및 GA3 처리가 발아에 미치는 영향을 구명하고자 수행하였다. 진퍼리꽃나무 종자는 국립수목원 전시원에서 채종 후 4℃에 저온건조 저장하였으며 전자현미경(DVM6, Leica Microsystems GmbH, Wetzlar, Germany)을 이용하여 종자와 배의 길이를 측정하였다. 2022년 3월에 growth chamber 내에서 32일간 15/6℃, 25/15℃ 변온조건하에 배양하였으며, 저온층적처리(0, 40일) 및 GA3 처리(0/500/1,000mg·L^-1) 처리에 따른 발아 특성을 구명하였다. 진퍼리꽃나무 종자의 최종발아율(FGP)은 25/15℃ GA3 1000mg·L^-1 처리에서 42.2%로 가장 높게 조사되었다. 평균발아일수(MGT)는 15/6℃ 저온층적 처리에서 22.3일로 가장 높았으며, 대부분 15/6℃ 변온조건에서 25/15℃ 변온조건보다 6∼8일 높았다. 최종발아일의 평균은 약 12일로 확인되었다. 저온 층적처리 결과, 최종발아율(FGP)은 온도조건 25/15℃, 15/6℃에서 각각 32.2%와 11.1%를 보여 무처리구에서 조사된 24.4%와 10.0%보다 각각 7.8%, 1.1% 높게 나타났다. 호르몬처리 결과, 동일한 발아조건에서 GA3 500mg·L^-1 처리보다 1000mg·L^-1 처리에서 더 높은 발아율을 보였다. GA3 1000mg·L^-1 처리에서의 최종발아율(FGP)DKSH은 25/15℃, 15/6℃ 각각 42.2%와 30.0%를 보여 무처리구 보다 각각 17.8%, 20% 높게 나타났다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.39-39
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• 2022

기온, 강수량 등 기후변화에 따른 식물 멸종이 증가함에 따라 기후변화에 민감한 북방계식물의 중요성이 증대되고 있는 실정이다. 본 연구 대상종의 큰금매화(Trollius chinensis)는 북한 및 북방계 식물로 고산 초지에서 자생하는 미나리아재비과 여러해살이풀이며, 기후변화에 직·간접적인 영향을 받고 있는 실정이다. 이에, 큰금매화의 발아조건을 규명하여 종 복원과 대량증식법 개발을 위한 기초자료를 확보하는 데 목적이 있다. 종자의 형태학적 특성은 원형~계란형(circular~obovate)에 작은 돌기가 겹겹이 있는(Colliculate) 형태였으며, 종피는 진갈색이다. 크기는 길이 1.37±0.741mm, 너비 0.81±0.531mm이었다. 종자의 단면을 확인한 결과, 배는 작은 선형태(Axial-miniature)이었으며, 종자는 91%의 충실도를 보였으며 TZ 테스트에서 모두 배가 전체적으로 붉은색으로 염색되어 양호한 활력을 보였다. 처리구별 발아실험 전 종자 소독은 파종 전 70% 에탄올 처리 후 2%의 NaOCl을 넣어 10분 동안 소독 후 멸균수로 5회 수세하고 멸균수를 제거하여 침지처리에 사용하였다. 발아실험 결과 종자의 최종발아율(FGP)은 15/6℃ GA3 1000mg·L^-1 처리에서 40.0%로 가장 높았다. 평균발아일수(MGT)는 15/6℃ 무처리에서 22.8일로 가장 높았으며, 최종발아일의 평균은 약 9.5일로 확인되었다. 대부분 GA3 처리에서 최종발아율(FGP)이 20% 이상 높게 나타났으며, GA3 500mg·L^-1 보다는 GA3 1000mg·L^-1의 조건에서 3.3~5.5% 최종발아율(FGP)이 향상된 것으로 확인되었다. 한편, 온도 조건 25/15℃ 무처리에서는 발아가 확인되지 않았다.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.390-402
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• 2023

Salmonella are Gram-negative pathogenic bacteria commonly found in food animals such as poultry and swine and potentially constitute risks and threats to food safety and public health through transmissible virulence and antimicrobial resistance (AMR) genes. Although there are previous studies in the Philippines regarding genotypic and phenotypic AMR in Salmonella, there are very few on virulence and their associations. Hence, this study collected 700 Salmonella isolates from swine samples in abattoirs and wet markets among four districts in Metro Manila and characterized their genotypic virulence and β-lactam AMR profiles. Gene frequency patterns and statistical associations between virulence and bla genes and comparisons based on location types (abattoirs and wet markets) and districts were also determined. High prevalence (>50%) of virulence genes was detected encompassing Salmonella pathogenicity islands (SPIs) 1-5 suggesting their pathogenic potential, but none possessed plasmid-borne virulence genes spvR and spvC. For bla, bla_TEM was detected with high prevalence (>45%) and revealed significant associations to four SPI genes, namely, avrA, hilA, mgtC, and spi4R, which suggest high resistance potential particularly to β-lactam antibiotics and relationships with pathogenicity that remain mechanistically unestablished until now. Lastly, comparisons of location types and districts showed variations in gene prevalence suggesting effects from environmental factors throughout the swine production chain. This study provides vital data on the genotypic virulence and AMR of Salmonella from swine in abattoirs and wet markets that suggest their pathogenicity and resistance potential for policymakers to implement enforced surveillance and regulations for the improvement of the Philippine swine industry.

• Korean Journal of Plant Resources
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• v.25 no.1
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• pp.132-141
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• 2012

This study was carried out to test seed germination responses to temperatures and pre-treatments in Hippophae rhamnoides, which has many abilities in antioxidant activity, soil improvement and erosion control. H. rhamnoides seeds were placed at 10, 15, 20, 25, 30 and $35^{\circ}C$ under light condition. As the results, germination percentage (GP) was the highest at 15 and $20^{\circ}C$, and mean germination time (MGT), germination rate (GR) and germination value (GV) were the highest at $25^{\circ}C$. Quadratic and linear regression model were used to determine the cardinal temperatures such as base ($T_b$), maximum ($T_m$) and optimum ($T_o$) temperature for germination. In quadratic regression model using PG, $T_b$, $T_m$ and $T_o$ was estimated as 0.6, 36.4 and $18.5^{\circ}C$, respectively, and temperature range for germination was $35.8^{\circ}C$. In linear regression model using GR, $T_b$, $T_m$ and $T_o$ was estimated as 8.3, 35.4 and $25.3^{\circ}C$, respectively, and temperature range for germination was $27.2^{\circ}C$. Germination properties were investigated after H. rhamnoides seeds were treated by prechilling (1, 2, 4, 6 and 8 weeks), stratification (2, 4, 6 and 8 weeks), solid matrix priming (seed : carrier : water = 5 : 1 : 7, 8, 9 and 10), osmo-priming (-0.25, -0.5, -1.0 and -1.5 MPa) and calcium chloride ($CaCl_2$) -priming (100, 200, 300 and 400 mM). The highest GP was observed in $CaCl_2$ 300 and 400 mM treatments, and MGT was the shortest in stratification 6 and 8 weeks treatments. GR and GV were the highest and GP was the second highest when seeds were prechilled for 1 and 2 weeks. Consequently, prechilling 1 or 2 weeks treatment was considered as the appropriate method when we contemplate qualitative and quantitative effects in seedling production.

• Environmental Mutagens and Carcinogens
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• v.25 no.2
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• pp.60-65
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• 2005

The human solute carrier, SLC41Al, is a $Mg^{2}+$ transporter that is regulated by extracellular magnesium. Although intracellular magnesium plays a fundamental role in cellular metabolism, little is known about how $Mg^{2}+$ is taken up and controlled by cells. Magnesium plays a fundamental role in cellular metabolism so that its control within the body is critical. Magnesium homeostasis is principally a balance between intestinal absorption of dietary magnesium and renal excretion of urinary magnesium. The kidney, mainly the distal convoluted tubule, controls magnesium reabsorption. Although renal reabsorption is under the influence of many hormones, selective regulation of magnesium transport is due to intrinsic control involving transcriptional processes and synthesis of transport proteins. Using microarray analysis, identification of the genetic elements involved with this transcriptional control has been begun. SLC41A1(GenBank Accession No. AJ514402), comprises 10 putative transmembrane domains, two of which are highly homologous to the integral membrane part of the prokaryote transports $Mg^{2}+$ and other divalent cations $Sr^2+,\;Zn^2+,\;Cu^2+,\;Fe^2+,\;Co^2+,\;Ba^2+,\;and\;Cd^2+,\;but\;not\;Ca^2+,\;Mn^2+,\;and\;Ni^2+.$ Transport of $Mg^{2}+$ by SLC41Al is rheogenic, voltage dependent, and not coupled to Na or Cl. Expressed SLC41Al transports a range of other divalent cations: $Mg^{2+},\;Sr^{2+},\;Zn^{2+},\;Cu^{2+},\;Fe^{2+},\;Co^{2+},\;Ba^{2+},\;and\;Cd^{2+}$. The divalent cations $Ca^{2+},\;Mn^{2+},\;and\;Ni^{2+}$and the trivalent ion $Gd^{3+}$ did not induce currents nor did they inhibit $Mg^{2+}$ transport. The nonselective cation $La^{3+}$ abolishes $Mg^{2+}$ uptake. Computer analysis of the SLC41Al protein structure reveals that it belongs to MgtE protein family & suggested that the human solute carrier, SLC41Al, might be a eukaryotic $Mg^{2+}$ transporter closely related $(60-70\%)$ protein encoded by SLC41A2 is a $Mg^{2}+$ transporter that might be involved in magnesium homeostasis in epithelial cells also transports a range of other divalent cations: $Ba^2,\;Ni^2,\;CO^2,\;Fe^2,\;or\;Mn^2,\;but\;not\;Ca^2,\;Zn^2,\;or\;Cu^{2+}$ that may have related functional properties.