목 적：확산강조 영상은 뇌질환 병변의 발견에 민감할 뿐 아니라 병변의 크기가 작아 발견이 어려울 때나 급성 및 아급성기의 뇌경색을 감별해 내는데 유용하게 사용된다. 그 밖에도 일반 MRI 검사로는 감별이 어려운 연부조직의 암과 양성종양을 확인 할 수 있어 근･골격계 검사에도 유용하게 사용된다. 하지만 해부학적 구조에 의해 자화감수성 차이 및 금속성 물질을 삽입한 환자에게서 EPI기법을 사용한 Diffusion 검사는 영상의 왜곡과 Artifact가 크게 나타나 영상에 대한 정확한 평가나 종양의 감별에 어려움을 겪게 된다. 이에 기존 Single-shot EPI 기법을 이용한 Diffusion검사에 비해 Metallic susceptibility artifact가 적은 IRIS Multi-shot Diffusion 기법의 SENSE factor와 Shot 수 변화에 따른 영상 변화를 확인하고자 하였다. 대상 및 방법：IRIS MS DWI 기법의 자기감수성 인공물과 기타 영상 평가를 위해 돼지고기에 실제 수술용 Metal pin을 삽입하여 인체와 유사한 Phantom을 제작하였다. 모든 검사는 IRIS MS DWI 기법을 이용하여 Phantom 영상을 획득하였 다. SENSE factor와 Shot 수의 변화에 따른 자기감수성 인공물의 왜곡도 및 영상 변화를 확인하기 위해 SENSE factor 1, 2, 3, 4 값에 Shot 수를 각각 2, 4, 6으로 변화시켜 실험을 진행하였고 두 가지 Parameter를 제외한 모든 Parameter는 동일하게 적용하여 영상을 획득하였다. 사용된 장비는 Philips medical system의 Ingenia 3.0T를 사용하였고, 신호수집 코일은 32 channel SENSE head coil을 사용하였고 모든 평가항목은 Infinitt healthcare사의 INFINITT PACS를 이용하여 측정하였다. 자기감수성 인공물의 왜곡도 평가는 각 평가 영상에서 인공물의 가장 긴 종축 길이를 5회씩 측정한 후 평균 값으로 산출하였고 정성적 평가는 5년 이상의 MRI 경력을 가진 전문방사선사 5인이 항목 당 1회씩 측정한 후 평균값으로 산출하였다. 결 과：같은 SENSE factor 일 때 Shot 수의 증가로 자기감수성 인공물의 왜곡도는 감소하였다. 또한 같은 shot수 일 때 SENSE factor의 증가 시에도 자기감수성 인공물의 왜곡도는 감소하였다. 자화감수성인공물 역시 SENSE factor와 Shot 수가 증가함에 따라 왜곡도의 정도가 감소하였으나 일정 Factor이상 후에는 같은 값을 나타내었다. 전체적인 Image quality 평가에서는 Shot수의 변화 보다는 SENSE factor의 변화시에 많은 영향을 주는 것을 알 수 있었고 과도한 SENSE factor 사용은 오히려 Image quality가 저하 된다는 것을 알 수 있었다. Ghost artifact의 발생은 SENSE factor 4 이상이 되었을 때 발생하였으며 이처럼 많은 SENSE factor의 사용은 Ghost artifact 발생시킬 수 있으므로 적절한 SENSE factor 사용이 필요할 것으로 생각된다. 결 론：본 연구에서는 IRIS MS DWI 기법의 SENSE factor와 Shot 수를 변화시켜 여러 가지 Artifact를 감소시키고 Scan time을 단축시킬 수 있는 방안을 찾을 수 있었다. 더욱이 IRIS MS DWI 기법의 사용은 기존의 Single shot DWI 기법에서의 문제점들을 보완할 수 있었고 다양한 검사부위를 더 좋은 Image quality로 획득 할 수 있는 의미 있는 실험이었다. 앞으로 실제 임상에서 환자의 상태나 의뢰된 검사 목적에 따라 본 논문의 결과를 활용한다면 보다 진단적 가치가 높은 영상을 획득할 수 있을 것으로 사료된다.

This study was conducted to investigate the feed value and silage quality according to storage period and film layers in whole crop oat silage. The crude protein content was increased in all silage during the storage periods compared to those before silage, under prolonged storage period slightly and the number of film layers of silage, six layer were higher than four layers, but no significant. NDF and ADF contents were also increased in all silage of storage duration compared to those before silage, but they was similar level between storage duration and number of film layers. TDN content was decreased of the storage duration. However, it was similar under the storage duration and the number of film layers. The pH value was decreased during prolonged storage period and six layers was lower than four layers depending on the film layers. In the organic acid contents, lactic acid and acetic acid were increased under the prolonged storage duration, and butyric acid was higher significantly(p<0.05), six layers of the film were showed higher lactic acid and lower butyric acid(p<0.05). Therefore, oat silage should be used within 6 months it was when treated with 4 layers, if considering the long-term storage, it is desirable to treat it with 6 layers or more.

본 연구는 구운 횟수에 따른 죽염의 미네랄 농도변화와 항우식 효과를 확인하기 위하여 수행하였다. 미네랄 변화는 9회 죽염에서 Na, K, Mn 그리고 Fe이 높게 나타났으며, Mg, Ca 및 SO4는 1회 죽염에 서 가장 높았다. 구강 병원균 2종에 대한 최소억제농도 측정 결과 S. mutans에 대한 죽염의 MIC는 25mg/mL으로 나타났으나 S. sanguinis에 대한 죽염의 MIC는 50mg/mL로 S. mutans에 대한 항균효 과가 S. sanguinis보다 높은 것으로 나타났으며, 2종의 균주 모두에 대해 천일염보다는 죽염의 항균효 과가 더 높은 것으로 나타났다. 더욱이, 3%의 죽염에서 구강 내 pH 환경이 pH≥5.5로 오래 지속되는 것으로 나타났다. 따라서, 본 연구 결과는 죽염이 치아우식과 치주질환을 감소시키는데 유용할 것이라 생각될 수 있겠으나 보다 세밀한 추가 연구가 진행되어야 할 것으로 판단된다.

A diverse of recommendation has been made for the structure and management of dairy cows, despite demanding research, the relationship between lactation number and various factors is yet to be established. The present study was aimed to investigate the covariance among lactation number, growth performance, calving interval, and milk production was considered to increase an efficiency of selection schemes and to manage more efficiently Holstein dairy cows that have been raised on small-scale family farms in Republic of Korea. For that purpose, the data were observed from 850 Holstein dairy cows, which a total of 3929 milking, since April 2016 - January 2017. We measured the body weight, height, age, calving interval, and milk production of the each dairy cow. Also, information about the date of lactation, calving interval, and milk production was recorded using an automatic milking system(AMS) with identification numbers. Milk production was calculated per udder quarter in the AMS. Our study results showed the increased average body weight(p>0.05) in 1, 2, 3, and 4th lactating dairy cows and afterwards, we noticed the tendency on the average body weight(p<0.05) per lactation progressed. There was no significant difference noticed on height measurement of dairy cows. From the processing data of 850 Holstein dairy cows, the lactation number 1 and 7 had a greater calving interval with significantly lowered milk production, and the lactation number 2, 3, 4, 5, and 6 had significantly lowered the calving interval(p<0.05) with a greater milk production. From our study results, we evidenced that there is a significant relationship between the lactation number, growth performance, calving interval, and milk yield, and the maximum production of milk occurring in the 3rd and 4th lactation dairy cows. The achieved results from this study can be used by the small-scale farmers to encourage the structure and management of growth performance, calving interval, and milk yield in Holstein dairy cows in Korea.

The electronic and optical characteristics of molybdenum disulphide (MoS2) film significantly vary with its thickness, and thus a rapid and accurate estimation of the number of MoS2 layers is critical in practical applications as well as in basic researches. Various existing methods are currently available for the thickness measurement, but each has drawbacks. Transmission electron microscopy allows actual counting of the MoS2 layers, but is very complicated and requires destructive processing of the sample to the point where it will no longer be useable after characterization. Atomic force microscopy, particularly when operated in the tapping mode, is likewise time-consuming and suffers from certain anomalies caused by an improperly chosen set point, that is, free amplitude in air for the cantilever. Raman spectroscopy is a quick characterization method for identifying one to a few layers, but the laser irradiation causes structural degradation of the MoS2. Optical microscopy works only when MoS2 is on a silicon substrate covered with SiO2 of 100~300 nm thickness. The last two optical methods are commonly limited in resolution to the micrometer range due to the diffraction limits of light. We report here a method of measuring the distribution of the number of MoS2 layers using a low voltage field emission electron microscope with acceleration voltages no greater than 1 kV. We found a linear relationship between the FESEM contrast and the number of MoS2 layers. This method can be used to characterize MoS2 samples at nanometer-level spatial resolution, which is below the limits of other methods.

목적 : 병원에 내원하는 근시 환자수를 통하여 유병률을 분석하고 의료비용을 통하여 근시 환자의 1인당 진료비의 변화추이를 분석하고자 하였다. 방법 : 건강보험심사평가원에서 제공하는 환자표본자료를 이용하여 근시로 병원에 내원한 외래 및 입원 환자를 대상으로 하였다. 유병률은 2015년도 인구총조사 데이터를 활용하였다. 결과 : 3년간 근시로 병원에 내원한 환자 수는 2015년도에 가장 많았으며, 외래진료가 대부분이었다. 남 성보다 여성의 환자수가 많았으며, 남성은 2016년도에 가장 많았고 여성은 2015년도에 가장 많았다. 의료기 관별 환자 수는 의원급이 가장 많았으며 보건기관 등이 가장 적었다. 지역별 환자 수는 서울과 경기지역이 많았으며 세종시가 가장 적었다. 근시 유병률은 인구 천 명당 남성은 25.15명, 여성은 30.17명으로 나타났 다. 의원급 요양기관의 유병률은 인구 천 명당 25.90명으로 가장 높게 나타났다. 광주지역의 유병률이 인구 천 명당 39.15명으로 가장 높게 나타났다. 근시로 내원하여 진료 받은 3년간 전체 평균 진료비는 서울이 가 장 많았으며, 대부분의 지역에서 2014년부터 2016년까지의 3년 동안 1인당 진료비가 증가하였다. 결론 : 근시로 병원을 내원하는 전체 환자수와 의료비용은 3년 동안 점차 증가하고 있는 추세이다. 이에 본 논문이 근시 환자의 안경원을 포함한 의료 서비스 이용 양상에 관한 기초자료로 도움이 될 것이라 생각한다.

The object of this study is to improve the straightness in tubular shaft production. Die bearings of 1, 2 and 3 were inserted onto the lower die, respectively. In this study, the tubular shafts at the stage 5 were modelled as the standard and error cases. The error case assumes the production error of raw material. The coefficient of friction was set to the Oil_Cold conditions as referring to the analysis library. In the results, the effective stress was observed homogeneously on the distribution at yoke top in standard case. However, the effective stress was observed on the distribution at long section of yoke in case of the raw material with error. The metal flow line was stretched straight in standard case. On the other hand, the metal flow line was bent in all of error cases. The biggest displacement occurred when only one die bearing was applied. The smallest displacement occurred when two die bearings were applied in lower die.

This study aimed to identify milling characteristics depending on the number of a cutting roller’s air vent and blowing velocity to remove rice bran by the cutting type milling machine which can minimize the conventional milling process. The level of whiteness was found to be 38±0.5 in all the conditions, showing consistent whiteness levels during milling. The rice temperatures turned out to be 15.4 and 14.6oC which were rather low-level under the conditions of the cutting roller with 3 vents and blowing velocities of 35 and 40 m/s respectively. Cracked rice ratio was 2.13% under the conditions of the cutting roller with 3 vents and a blowing velocity of 35 m/s. Broken rice ratio showed the range of 0.762-0.869%, reflecting a low level. Turbidity after milling was decreased, as blowing velocity became faster. Energy consumption for milled rice production was decreased, as blowing velocity became faster. The optimum milling condition for cutting type milling machine depending on air vent number of cutting roller and blowing velocity was found to be 3 vents and 35 m/s.

This study aimed to identify milling characteristics depending on the number of a cutting roller’s air vent and blowing velocity to remove rice bran by the cutting type milling machine which can minimize the conventional milling process. The level of whiteness was found to be 38±0.5 in all the conditions, showing consistent whiteness levels during milling. The rice temperatures turned out to be 15.4 and 14.6oC which were rather low-level under the conditions of the cutting roller with 3 vents and blowing velocities of 35 and 40 m/s respectively. Cracked rice ratio was 2.13% under the conditions of the cutting roller with 3 vents and a blowing velocity of 35 m/s. Broken rice ratio showed the range of 0.762-0.869%, reflecting a low level. Turbidity after milling was decreased, as blowing velocity became faster. Energy consumption for milled rice production was decreased, as blowing velocity became faster. The optimum milling condition for cutting type milling machine depending on air vent number of cutting roller and blowing velocity was found to be 3 vents and 35 m/s.

Previously, we reported a quantitative trait locus (QTL) that affect total teat number (TTN) on pig chromosome 7 (SSC7) in a large F2 intercross population between Landrace and Korean native pigs. The aim of this study was to refine the QTL associated with TTN and to identify positional candidate gene(s) within the refined genomic region. TTN was recorded in 1,105 F2 progeny. All experimental animals were genotyped using 998 informative single nucleotide polymorphism (SNP) markers located on SSC7. A haplotype-based linkage and association analysis using the PHASEBOOK programme was applied to perform high-resolution QTL analysis. Additionally, linear mixed-effect models were used to assess the effect of a positional candidate gene on TTN and other economically important traits [i.e., thoracic vertebrae number (THO), carcass body length (CBL) and weight (CW), back fat thickness (BFT) and intramuscular fat content (IMF) in loin muscles]. Joint linkage and association analysis refined the critical region to a 1.07 Mb region that included a novel positional candidate gene, BRMS1L, that encodes the breast cancer metastasis-suppressor 1-like protein, which could possibly be implicated in normal mammary gland development. Significant association of an SNP marker (g.-1087 G>A) in the 5’-flanking region of BRMS1L with TTN (P=1.10x10-8), THO (P=5.80x10-4), and CBL (P=0.038) was observed. Based on these data, we propose BRMS1L as a positional candidate gene for TTN in pigs. After validation of the association in other independent populations and further functional studies, these results could be useful in optimizing breeding programmes that improve TTN and other economically important traits in swine

The autoregressive method provides a univariate procedure to predict the future sunspot number (SSN) based on past record. The strength of this method lies in the possibility that from past data it yields the SSN in the future as a function of time. On the other hand, its major limitation comes from the intrinsic complexity of solar magnetic activity that may deviate from the linear stationary process assumption that is the basis of the autoregressive model. By analyzing the residual errors produced by the method, we have obtained the following conclusions: (1) the optimal duration of the past time for the forecast is found to be 8.5 years; (2) the standard error increases with prediction horizon and the errors are mostly systematic ones resulting from the incompleteness of the autoregressive model; (3) there is a tendency that the predicted value is underestimated in the activity rising phase, while it is overestimated in the declining phase; (5) the model prediction of a new Solar Cycle is fairly good when it is similar to the previous one, but is bad when the new cycle is much different from the previous one; (6) a reasonably good prediction of a new cycle can be made using the AR model 1.5 years after the start of the cycle. In addition, we predict the next cycle (Solar Cycle 25) will reach the peak in 2024 at the activity level similar to the current cycle.

The unique characteristics of graphene make it an optimal material for crucial studies; likewise, its potential applications are numerous. Graphene’s characteristics change with the number of total layers, and thus the rapid and accurate estimation of the number of graphene layers is essential. In this work, we review the methods till date used to identify the number of layers but they incorporate certain drawbacks and limitations. To overcome the limitations, a combination of these methods will provide a direct approach to identify the number of layers. Here we correlate the data obtained from Raman spectroscopy, optical microscopy images, and atomic force microscopy to identify the number of graphene layers. Among these methods, correlation of optical microscopy images with Raman spectroscopy data is proposed as a more direct approach to reliably determine the number of graphene layers.

The aim of this study was to identify quantitative trait loci (QTLs) influencing teat number traits in an F2 intercross between Landrace and Korean native pigs (KNP). Three teat number traits (left, right, and total) were measured in 1105 F2 progeny. All experimental animals were genotyped with 173 informative microsatellite markers located throughout the pig genome. We detect that seven chromosomes harbored QTLs for teat number traits: genome regions on SSC1, 3, 7, 8, 10, 11, and 13. Six of fourteen identified QTL reached genome-wide significance. In SSC7, we identified a major QTL affecting total teat number that accounted for 5.6% of the phenotypic variance, which was the highest test statistic (F-ratio = 61.1 under the additive model, nominal P = 1.3×10-14) observed in this study. In this region, QTL for left and right teat number were also detected with genome-wide significance. With exception of the QTL in SSC10, the allele from KNP in all 6 identified QTLs was associated with decreased phenotypic values. In conclusion, our study identified both previously reported and novel QTL affecting teat number traits. These results can play an important role in determining the genetic structure underlying the variation of teat number in pigs.

멸종위기종 개체군의 연령구조를 파악하는 것은 개체군의 변동에 관한 정보를 제공할 수 있기 때문에 중요하다. 본 연구에서는 환경부 멸종위기종 Ⅱ급과 문화재청 천연기념물로 지정되어 있는 남생이 (Mauremys reevesii)의 등갑에 나타나는 성장선으로 실제 연령을 신뢰성 있게 예측할 수 있는지를 평가하였다. 실험개체는 실 연령이 1-9살인 서울동 물원에서 사육하는 100개체였다. 성장선은 중앙 추갑판 네 개와 좌우측 첫 번째 늑갑판에서 측정하였다. 연구결과 실 연령 1-5살까지는 성장선의 수가 실 연령보다 많았으나, 6-9살에는 성장선의 수가 실 연령보다 적었다. 실 연령과 성장선 연령을 비교 평가한 결과 성장선으로 실 연령을 예측하는 것은 6살 이하에서 제한적으로 가능한 것으로 나타났 다. 본 연구에서 또한 어린 개체와 암컷 남생이들의 등갑의 길이와 너비를 이용하여 나이를 예측하는 수식을 제공하였으 나 연구에 사용한 남생이들의 나이가 실 연령이 어린개체들이 대부분이어서 신뢰성 있는 연령예측은 가능하지 않았다. 종합하면, 등갑에 나타난 성장선을 이용하여 남생이의 실 연령의 예측하는 경우, 성장선 6개 이하는 성장선 수의 최소값을 7개부터는 최대값을 이용하는 것이 가능한 실 연령과의 편차를 줄 일 수 있음을 보여준다. 우리의 연구결과가 비록 제한적이기는 하지만, 국내에서 거북류의 성장선의 수를 이용하여 실 연령을 예측한 첫 번째 연구로, 야외에서 멸종위기종인 남생이의 연령을 평가할 때 유용하게 사용될 것으로 판단된다.

The survival rate and number of parasitized host of Encarsia formosa Gahan and Eretmocerus eremicus Rose were observed at low temperature conditions (6, 8, 10 and 12 ± 1oC, RH 70 ± 10%, in dark condition. Mummy of Encarsia formosa was stored at 12oC, for 70% of the mummies survived for 10 days. After 6-days storage at 12oC, number of parasitized host of the parasitoids was decreased to 35.9 (67.6%, compared to control). Mummy of Eretmocerus eremicus was stored at 12oC, and 70% of the mummies survived for 14 days. After 6-days storage at 12oC, number of parasitized host was decreased to 31.6 (83.6%, compared to control). Our results suggest that 12oC was most suitable temperature for storage of Encarsia formosa and Eretmocerus eremicus.

Chinese Character studies have mainly been focused on four areas: orthography, phonology, meaning, and character frequency. To add a new dimension to the existing approaches, this paper will provide and examine a quantitative data about the range of the vocabulary in Chinese character dictionaries. As a promising new method, the new approach, both diachronic and dynamic, will be very useful in exploring changing aspects of Chinese Characters usage, compared with the existing synchronic and static approaches. This paper aims to provide analysis of all Chinese Characters included in Chŏnun-okp'yŏn, the most authoritative dictionary of Joseon dynasty published in 1805 meaning ‘Chinese Rhyme Dictionary’, and in Sinjajeon, meaning ‘New Dictionary of Chinese Characters’ published in 1915, to explain their changing aspects in the entries of two dictionaries, and then to show how social change affected the use of Chinese Characters in early twentieth-century Korea. To that end, I construct the database of the two dictionaries on the basis of a detailed analysis of all the characters with respect to the radicals, strokes, components, and structures of these characters, which shows that Chŏnun-okp'yŏn includes 10,997 Chinese characters and Sinjajeon contains 13,348 characters with 13,084 in the body text and 264 in three appendices. 2,114 characters were newly inserted and 7 characters were removed in the body text of Sinjaeon. In particular, the number of the radical headings containing more than 20 newly inserted characters are 35, with 1,624 new characters in total, accounting for 77.1% of the total. The total number of radical headings including more than 30% newly inserted characters are 26. In addition, the number of radical headings containing more than 10 newly inserted characters with a growth rate of more than 20% is 903, accounting for 43% of the total number of characters. Based on these data, modern Koreans appears to have a wider vocabulary consisted of Chinese characters. The number of characters under the radicals meaning animal and plant ( 犬 (dog), 牛 (cow), 肉 (meat), 木 (tree), 米 (rice), 禾 (pine), 田 (farmland), 虫 (insect) etc.), those meaning mineral (石 (stone), 玉 (jade), etc), those meaning industrial products (皮 (leather), 巾 (towel) ect.), those meaning pathology (疒 (illness), 歹 (broken bones), etc.), increased quite a bit, the words reflecting newly emerged phenomena of industrialization or modernization in the early 20th century. In addition, it can be pointed out that the words used for spoken Chinese newly appears in Sinjaeon.