• Journal of radiological science and technology
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• 제39권1호
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• pp.51-57
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• 2016

Acoustic noise during magnetic resonance imaging (MRI) is the main source for patient discomfort. we report our preliminary experience with this technique in neuroimaging with regard to subjective and objective noise levels and image quality. 60 patients(29 males, 31 females, average age of 60.1) underwent routine brain MRI with 3.0 Tesla (MAGNETOM Tim Trio; Siemens, Germany) system and 12-channel head coil. Q-$T_2$ and $T_2$ sequence were performed. Measurement of sound pressure levels (SPL) and heart rate on Q-$T_2$ and $T_2$ was performed respectively. Quantitative analysis was carried out by measuring the SNR, CNR, and SIR values of Q-$T_2$, $T_2$ and a statistical analysis was performed using independent sample T-test. Qualitative analysis was evaluated by the eyes for the overall quality image of Q-$T_2$ and $T_2$. A 5-point evaluation scale was used, including excellent(5), good(4), fair(3), poor(2), and unacceptable(1). The average noise and peak noise decreased by $15dB_A$ and $10dB_A$ on $T_2$ and Q-$T_2$ test. Also, the average value of heartbeat rate was lower in Q-$T_2$ for 120 seconds in each test, but there was no statistical significance. The quantitative analysis showed that there was no significant difference between CNR and SIR, and there was a significant difference (p<0.05) as SNR had a lower average value on Q-$T_2$. According to the qualitative analysis, the overall quality image of 59 case $T_2$ and Q-$T_2$ was evaluated as excellent at 5 points, and 1 case was evaluated as good at 4 points due to a motion artifact. Q-$T_2$ is a promising technique for acoustic noise reduction and improved patient comfort.

• Korean Security Journal
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• 제29호
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• pp.139-162
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• 2011

The purpose of this study is to compare with the general and behavioral characteristics between simple and serial arsonists using the data derived from Scientific Crime Analysis System, Criminal Filing Search System, and Crime Information Management System. The analysis and findings reported here are derived from data extracted from 160 arsonists arrested by police officer. The independent variables included such socio-economic characteristic as arsonists' gender, age, occupation, education level, and previous criminal records of arsonists, and finally the general characteristics of the scene of fire settings. The dependent variable is whether or not serial fire setter. To achieve the purpose, the analysis of frequencies and cross-tab were conducted. According to frequence and cross-tab analysis, there are great differences of the general and behavior characteristics between two groups. In the comparison of simple and serial arsonists, serial arsonists are more likely to have previous criminal records, low socio-economic status, unmarried and no cohabitants than simple arsonists. furthermore, serial arsonists are more likely to use garbage papers for fire setting in the scene of the crime, to have mental or psychological problems, and to get involved in fire setting for the psychological pleasure than simple arsonists do. The present research has some obvious limitations. First, the analysis is based only on arsonists arrested by police officers. These may be considerable differences in arsonists arrested by police officers and fire setters not arrested by them. Additional research is needed to assess the extent to which these findings would apply to fire setters not arrested by police officer in Korea. Secondly, the data in this study are cross-sectional and simple cross-tab analysis are used. Potential limitation of cross-sectional data concerns the inability to specify the changes in measures as arsonists behavioral characteristics. Therefore, further studies need to use longitudinal data and more complicate statistical techniques such as correlation analysis, multiple regression analysis, or LISREL models to specify the casual relationships between dependent and independent variables for fire settings. Even if this study has some limitations, it is meaningful in which it first investigated the comparison of simple and serial arsonists focusing on the general and behavioral characteristics between two groups in Korea.

• Korean Journal of Heritage: History & Science
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• 제53권2호
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• pp.270-285
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• 2020

This study examines the state of archeological research on Silla and Unified Silla conducted in North Korea and identifies its characteristics. In South Korea, most research has focused on prehistoric times in North Korea, and little research has been done on Silla and Unified Silla. Noting this, we attempted to examine the history of archaeological research in North Korea to provide foundations upon which to go forward. The research was examined in terms of general archaeological themes including tombs, fortresses, the capital city, earthenware, roof tiles, ornaments, weapons, and horse harnesses, and we identified four characteristics from the examination. First, Juche ideology had a great influence on interpretation of the unification of the three kingdoms. The Juche ideology was first proposed in 1955, and at the time, it was not fully established as an ideology but rather seen as constituting opposition to toadyism. Accordingly, the unification of the three kingdoms led by Silla was seen as amounting to collusion with foreign forces and was not acknowledged. A piece of evidence shows that this change took place around 1962. Second, an inclination to testify to the 'uniqueness' of the cultures of the three kingdoms is observed. The argument is that culture in the Korean peninsula has unique characteristics that set it apart from Chinese culture, and that the cultures of the three kingdoms share much in common. This inclination was not mentioned in research until the 1950s, and it can be seen as an effort to comply with Juche ideology and prove the principle of unity as stated in the national leader's instructions in the 1960s. Third, the influence of Goguryeo on the formation of Silla culture is emphasized. Related research explains that Baekje, Silla, and Gaya adopted the 'superior' culture of Goguryeo, and could establish 'uniqueness' of culture accordingly. It is claimed that an advanced Goguryeo culture was disseminated throughout Balhae and Unified Silla, and then to Goryeo, resulting in a true unification of the ethnic culture. Fourth, researchers in North Korea presume the Silla tombs and other relics to be far older than South Korean researchers' estimate. From a standpoint of highlighting the long history of Korea, they estimate the Silla Dynasty was founded in the early or mid-first century. Accordingly, archeological evidence that demonstrates the establishment of the state is dated as far back. Such an estimate is also indispensable in justifying the explanation that the chamber tombs of Goguryeo had a direct influence on Silla. These research characteristics which arose during the 1960s continue to be basic guidelines for North Korean researchers.

• Korean Journal of Heritage: History & Science
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• 제53권2호
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• pp.64-87
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• 2020

Copper trihydroxychloride (atacamite, botallackite, paratacamite, etc.), the first green pigment used in Mogao Grotto's mural paintings of China, has been known as "copper green", "green salt", and "salt green", etc. and has been used as an important green pigment with malachite. At first, the natural mineral atacamite was employed, but after the Five Dynasties (907~960 CE), synthetic copper trihydroxychloride was primarily used. In Chinese literature, copper green, green salt, and salt green are recorded as being made via reaction with copper powder, Gwangmyeongyeom (natural sodium chloride), and Yosa (natural ammonium chloride), and the prepared material was analyzed to be copper trihydroxychloride. Copper trihydroxychloride pigment was not found in paintings prior to the Joseon Dynasty (1392~1910 CE) in Korea. In analysis of the green pigments used in paintings and the architectural paintworks in the Joseon Dynasty, copper trihydroxychloride was also shown to have been used as an important green pigment with malachite (Seokrok). In particular, the proportion of copper trihydroxychloride use was high in Buddhist paintings, shamanic paintings, and dancheongs (decorative coloring on wooden buildings). Some of these turned out to be synthetic copper trihydroxychloride, but it is unclear whether the rest of them are synthetic or natural pigments due to a lack of analyzed data. From literature and painting analyses, the pigment name of copper trihydroxychloride in the Joseon Dynasty turns out to be Hayeob, a dark green pigment. It is believed to have first been prepared by learning from China in the early Joseon period (early 15^th century) and its use continued until the late 19^th century with imported Chinese pigment. Round or oval particles with a dark core of copper trihydroxychloride which were used in Chinese literature were similar to the synthetic copper trihydroxychloride pigments used in the Joseon Dynasty and Chinese paintings. Therefore, the synthetic copper trihydroxychloride pigments of Korea and China are believed to have been prepared in a similar way.

• Radiation Oncology Journal
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• 제16권1호
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• pp.71-79
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• 1998

Purpose : The objective of this study is to introduce our installation of a non-commercial 3D Planning system, Plunc and confirm it's clinical applicability in various treatment situations. Materials and Methods : We obtained source codes of Plunc, offered by University of North Carolina and installed them on a Pentium Pro 200MHz (128MB RAM, Millenium VGA) with Linux operating system. To examine accuracy of dose distributions calculated by Plunc, we input beam data of 6MV Photon of our linear accelerator(Siemens MXE 6740) including tissue-maximum ratio, scatter-maximum ratio, attenuation coefficients and shapes of wedge filters. After then, we compared values of dose distributions(Percent depth dose; PDD, dose profiles with and without wedge filters, oblique incident beam, and dose distributions under air-gap) calculated by Plunc with measured values. Results : Plunc operated in almost real time except spending about 10 seconds in full volume dose distribution and dose-volume histogram(DVH) on the PC described above. As compared with measurements for irradiations of 90-cm 550 and 10-cm depth isocenter, the PDD curves calculated by Plunc did not exceed $1\%$ of inaccuracies except buildup region. For dose profiles with and without wedge filter, the calculated ones are accurate within $2\%$ except low-dose region outside irradiations where Plunc showed $5\%$ of dose reduction. For the oblique incident beam, it showed a good agreement except low dose region below $30\%$ of isocenter dose. In the case of dose distribution under air-gap, there was $5\%$ errors of the central-axis dose. Conclusion : By comparing photon dose calculations using the Plunc with measurements, we confirmed that Plunc showed acceptable accuracies about $2-5\%$ in typical treatment situations which was comparable to commercial planning systems using correction-based a1gorithms. Plunc does not have a function for electron beam planning up to the present. However, it is possible to implement electron dose calculation modules or more accurate photon dose calculation into the Plunc system. Plunc is shown to be useful to clear many limitations of 2D planning systems in clinics where a commercial 3D planning system is not available.

• Korean Journal of Weed Science
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• 제15권2호
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• pp.105-114
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• 1995

Differences in critical period of weed competition were investigated among five types of rice(Oryza sativa L.) cultivation. Increase in weed-free period resulted in 1-2 days delay of heading date in machine transplanting and direct-seeding as compared with complete weed-free plot. When weedy period increased, there was no difference in heading date in transplanting cultivations. In direct-seeding, however, weedy period of 7-10 weeks after seeding(WAS) resulted in 4-7 days delay of heading date, whereas further increase in the weedy period caused rather 5-6 days advance in heading date. Weed-free period did not significantly affect yield components in conventional hand transplanting. In machine transplanting with 30-day-old seedling decreases in percent ripening and 1,000-grain weight were caused by weeds emerged within 4 weeks after transplanting(WAT). All yield components were decreased due to weedy period in machine transplanting with 10-day-old seedling. In direct-seeding weedy periods caused to decrease in number of panicles, number of spikelets, percent ripening, and 1,000-grain weight were 8-9, 4-5, 3-4, and 8-10 WAS, respectively. The critical periods of weed competition were determined as the following. In conventional hand transplanting weed-free must be maintained for either 4 weeks after transplanting or the rest period after 8 WAT. In machine transplanting with 30-day-old seedling weed-free must keep for either 5 weeks after transplanting or the rest period after 8 WAT. In machine transplanting with 10-day-old seedling weeds must be removed for either 5 weeks after transplanting or the rest period after 7 WAT. Weed-free must be kept between 5 and 7 WAS in flood direct-seeded rice and between 6 and 9 WAS in dry direct-seeded rice.

• Proceedings of the Mineralogical Society of Korea Conference
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• 한국광물학회.한국암석학회 2003년도 공동학술발표회 논문집
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• pp.84-85
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• 2003

소백산육괴의 동부에 분포하는 영양-울진지역의 선캠브리아기 변성암류는 평해층, 기성층, 원남층, 평해화강편마암, 하다우백질화강편마암 등으로 구성되어 있다(김옥준 외, 1963). 그러나, 최근 김남훈 외(2001, 2002)은 야외조사연구와 암석학적 및 지구화학적 연구를 통하여 주로 변성화산암류로 기재되었던 기성층은 변성화산암류가 아니라 평해층과 원남층에서 산출되는 화강암질편마암과 각섬암 기원의 변성암류가 연성전단변형을 받아 형성된 압쇄암 내지 초압쇄암으로 되어 있고, 기존의 기성층은 변성화산암류와 같이 성분상으로 구분되는 별개의 층이 아닌 구조적으로 만들어진 연성전단대의 중심부일 가능성을 시사한 바가 있다. 본 연구는 연성전단대의 연장성 및 연성전단대 형성과 관련된 지구조운동의 특성을 파악하고, 중첩된 변형구조들의 선후관계로부터 영양-울진지역 선캠브리아기 변성암류에 대한 변형작용사를 규명하기 위해 기성층의 분포지를 중심으로 이 지역 선캠브리아기 변성암류에 대한 상세한 야외지질조사를 실시하였다. 그 결과, 예천(북후면-평은면)지역을 통과하여 봉화 부근에서 동북동-서남서 방향이 동-서 방향으로 전환하여 장군봉지역까지 연장되는 것으로 알려져 있는 우수 주향 이동성 예천전단대(KIGAM, 1995; 강지훈 외 1997; 강지훈, 2000; 강지훈과 김형식, 2000)는 영양-울진지역까지 연장됨이 확인된다. 또한, 영양-울진지역의 선캠브리아기 변성암류에는 연성전단변형 이전에 적어도 한 번의 습곡작용과 이후에 적어도 두 번의 습곡작용이 인지된다. 각 변형단계별 특징적인 구조요소를 요약하면 다음과 같다. D1 변형: 편마면 내지 편리(S0)가 습곡되어 형성된 F1 습곡은 동-서 방향의 준 수평적인 습곡축을 갖는 뿌리 없는 등사습곡 형태로 인지된다. 양 날개부의 S0 엽리는 F1 습곡축면(S1)으로 완전히 전위된 하나의 엽리(S0-1)로 나타나고, S0-1 엽리는 이 지역의 광역엽리로 인지된다. S0-1 광역엽리는 구성암류의 대상 분포 방향과 유사한 서북서 주향에 북쪽으로 중각 경사하는 집중된 방향성을 보이며 분산되어 나타난다. D2 변형: 변형구조로는 신장선구조, 압쇄구조면, 비대칭습곡 등으로 인지된다. 신장선구조는 S0-1 엽리면상에서 주로 신장된 석영(집합체)과 장석(집합체)들의 정향배열에 의해 정의되고, S0-1 엽리의 주향 방향으로 저각으로 침강하는 집중된 방향성을 보이며 분산되어 나타난다. 신장선구조에 평행하고 S0-1 엽리에 수직한 단면에서는 상부-동쪽-이동의 우수주향 이동성 연성 전단운동감각을 지시하는 구조요소들이 다량 관찰된다. 연성전단변형에 의해 형성된 압쇄구조면은 전단엽리와 압쇄엽리에 각각 해당하는 C면과 S면 등이 인지된다. 전단엽리 C면은 S0-1 광역엽리와 거의 일치하고, 압쇄엽리 S면은 F2 비대칭습곡의 축면엽리와 거의 일치한다. S0-1 엽리를 습곡시키는 F2 비대칭습곡은 S0-1 엽리를 전단면으로 하여 상부-동쪽-이동 전단운동에 의해 형성된 밀착습곡 형태로 인지된다. F2 습곡축은 북동 방향으로 중각 내지 저각 침강하고 F1 습곡축과는 65$^{\circ}$-75$^{\circ}$ 범위의 사이각을 이룬다. F2 습곡축면은 동북동 주향에 북쪽으로 중각으로 경사하고 F1 습곡축면과는 20$^{\circ}$-40$^{\circ}$ 범위의 사이각을 이룬다. D3 변형. S0-1 엽리와 압쇄구조면 등을 습곡시키는 F3 습곡은 준 수평적인 습곡축과 습곡축면을 갖는 개방 횡와습곡의 형태로 인지된다. D4 변형: F4 습곡은 비대칭 공역성 킹크습곡, 공역성 충상단층에 수반되어 나타나는 드래그습곡, 대칭 개방 직림습곡 등의 다양한 습곡 형태로 인지된다. 이들 F4 습곡의 축면엽리는 일반적으로 동-서 주향에 남쪽과 북쪽으로 경사한다. 그 경사각은 비대칭 공역성 킹크습곡(저각), 드래그습곡(중각), 대칭 개방 직립습곡(고각) 순으로 고각을 이룬다. F4 습곡축은 동쪽과 서쪽으로 저각 침강하는 집중된 방향성을 보인다. 공역성 충상단층은 동-서 주향에 남쪽과 북쪽으로 경사하는 단층면과 상부가 북쪽과 남쪽으로 충상하는 운동상을 보인다. 드래그습곡의 축면엽리는 이러한 공역성 충상단층운동의 전단압축방향에 수직으로 발달한다. 이러한 D4 변형구조는 남-북 방향의 압축 지구조 환경하에서 형성된 것으로 고찰된다.

• Journal of Korean Ophthalmic Optics Society
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• 제13권3호
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• pp.1-6
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• 2008

Purpose: Plastic optical monomer materials having ultra high refractive index have an income of the whole quantity from advanced nations to domestic companies which are related to plastic optical lens. It is necessary to develop novel plastic optical lens materials in order to overcome a FTA provision and revitalize a stagnating optical lens industry in the interior optical lens industries. The new plastic optical lens materials against the substitution effect of income should be gradually demanded. This work will be synthesized novel super high refractive monomer resin materials of urethane lens series and studied the properties of optical lens using it. Methods: ETS-4 (2-(2-mercaptoethylthio)-3-{2-[3-mercapto-2-(2-mercaptoethylthio)propyl thio]ethylthio}propane -1-thiol), which is optical lens monomer resin having super high refractive index, was synthesized and identified its structure and property by elemental analysis, EI-MS, TGA, FT-IR spectroscopy, $^1H$ and $^{13}C$ NMR spectroscopies. After mixing evenly from mixed monomer resin and diisocyanate series, it was casting in glass mold. After thermal curing, the obtained optical lenses were measured and compared with the refractive index and Abbe number for studies of their optical properties. Results: We have synthesized the novel ultra high refractive index monomer resin, ETS-4, and have identified its structure and property by elemental analysis, EI-MS, TGA, FT-IR spectroscopy, $^1H$ and $^{13}C$ NMR spectroscopies. The existence of three isomers for EST-4 was identified by $^{13}C$ NMR spectroscopy. The refractive index ($N_d$ at $25^{\circ}C$) of monomer resin in liquid state obtained from the Abbe refractometer was 1.647. The refractive indexes of raw plastic optical lenses prepared from the mixed ETS-4 monomer and diisocyanate series were in the range of 1.656~1.680. Conclusions: Novel super high refractive index plastic optical lens monomer was synthesized and analysed, the optical lenses prepared using it were colorless transparency and excellent properties. It is of utility for the industrialization.

• The Korean Journal of Nuclear Medicine
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• 제39권3호
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• pp.174-181
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• 2005

Purpose: Reduction of respiratory motion artifacts in PET images was studied using respiratory-gated PET (RGPET) with moving phantom. Especially a method of generating simulated helical CT images from 4D-CT datasets was developed and applied to a respiratory specific RGPET images for more accurate attenuation correction. Materials and Methods: Using a motion phantom with periodicity of 6 seconds and linear motion amplitude of 26 mm, PET/CT (Discovery ST: GEMS) scans with and without respiratory gating were obtained for one syringe and two vials with each volume of 3, 10, and 30 ml respectively. RPM (Real-Time Position Management, Varian) was used for tracking motion during PET/CT scanning. Ten datasets of RGPET and 4D-CT corresponding to every 10% phase intervals were acquired. from the positions, sizes, and uptake values of each subject on the resultant phase specific PET and CT datasets, the correlations between motion artifacts in PET and CT images and the size of motion relative to the size of subject were analyzed. Results: The center positions of three vials in RGPET and 4D-CT agree well with the actual position within the estimated error. However, volumes of subjects in non-gated PET images increase proportional to relative motion size and were overestimated as much as 250% when the motion amplitude was increased two times larger than the size of the subject. On the contrary, the corresponding maximal uptake value was reduced to about 50%. Conclusion: RGPET is demonstrated to remove respiratory motion artifacts in PET imaging, and moreover, more precise image fusion and more accurate attenuation correction is possible by combining with 4D-CT.

• The Korean Journal of Nuclear Medicine
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• 제33권4호
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• pp.388-397
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• 1999

Purpose: Propranolol is known to decrease portal pressure by reducing blood flow of portal vein. Perrectal portal scintigraphy with Tc-99m pertechnetate has been introduced to evaluate the portal circulation and early diagnosis of liver cirrhosis. We evaluated the effects of propranolol on portal circulation by using per-rectal portal scintigraphy. Materials and Methods: We analyzed the portal hemodynamics by per-rectal portal scintigraphy in 51 patients with liver cirrhosis, 10 chronic hepatitis and 10 normal subjects. 38 patients with cirrhosis underwent per-rectal portal scintigraphy before and after propranolol medication. Perrectal portal scintigraphy was performed after per-rectal administration of 370 MBq of Tc-99m pertechnetate. The shunt index was calculated as the ratio, expressed as a percentage of heart radioactivity to the sum of heart and liver radioactivity during the first 30 seconds. Results: The shunt index in 40 patients with cirrhosis ($59.8{\pm}27.2%$) was significantly higher than that of normal control ($5.0{\pm}1.2%$. p<0.01) and chronic hepatitis ($11.4{\pm}3.5%$, p<0.01). Shunt index was significantly different according to Child's classification and the degree of esophageal varix (p<0.01). After propranolol medication, shunt index was significantly decreased from $59.9{\pm}27.3%$ to $51.3{\pm}15.3%$ (p<0.01) in 38 patients with liver cirrhosis. There was no significant difference of the amount of shunt index reduction after propranolol according to Childs' classification and the degree of esophgageal varix. Conclusion : The effect of propranolol on portal circulation was demonstrated as decreasing shunt index on per-rectal portal scintigraphy in patients with liver cirrhosis. Per-rectal portal scintigraphy may be useful to evaluate the portal circulation and to predict the effect of propranolol in patients with liver cirrhosis.