• Economic and Environmental Geology
• /
• v.7 no.3
• /
• pp.87-100
• /
• 1974

This paper deals with grain size analysis, heavy mineral analysis and trace element analysis of the recent sediments of Han River basin between Cheongpyong, Gyeonggi province and Seoul. For each location the samples are taken at river shoreline, river berm and river dune. The size analysis discloses that the mean values range from $-1.37{\phi}$ to $-1.60{\phi}$, sorting values range from 0.25 to 1.84, skewness values range from -0.44 to 0.51 and kurtosis values range from -0.1 to 1.75. Based on the textural parameters, the dune sand can be distinguished from the shoreline-berm sand. The content of heavy minerals of each sample ranges from 0.04 to 4.7%. The principal heavy minerals are ilmenite, magnetite, leucoxene, garnet, amphibole, pyroxene, kyanite, zircon, monazite, tourmaline, epidote, limonite, and minor minerals are apatite, sillimanite, andalusite and olivine. In general, dune sand samples contain more heavy minerals than the samples of shoreline or berm sand. This suggests that the heavy mineral concentration is affected by wind action more than by any other causes. The content of ilmenite and leucoxene decreases, whereas the content of zircon and epidote increases as it approaches the downstream region. The differences result from the variance of geological occurrences. The emission spectrochemical analysis and colorimetry analysis revealed that the content of Ni and V in the heavy minerals of the study area are higher than those of other stream sediments in Korea. On the other hand the content of Cu, Ph, Zn, Mo, W, P, Mn, Cr, Ag and Sn are lower in the study area. It has been observed also that the contents of all the elements except for Bi are higher in this area than the samples of marine sediments of Yellow Sea.

• Design & Manufacturing
• /
• v.10 no.1
• /
• pp.51-54
• /
• 2016

Metal sheet forming has been commonly used as the core technology in manufacturing parts of automobiles. It guarantees the highest production rate due to the process of mass production employing the press die. For precision of the product, the accuracy of the molds and its mechanic structures are considered as essential factors. One of these is fine blanking, which is utilized for the production of the metal sheet spring, with which clear sheer surfaces can be achieved in one operation from the materials. However, the current designs of press dies perform the forming analysis with the molds of rigid body, so they are focused on weight lightening by a rule of thumb. Therefore, this paper practice structural analysis about developing the semi fine-fine blanking technology. The semi fine-blanking can be run through the combination of the hydraulic cylinders and normal presses, so this paper analyze the amount of deformation according to the oil pressure. In addition, based on the plasticity of 50CrV4, the materials of the mold parts, the structural analysis and life analysis are proceeded, so they are expected to be useful as data for manufacturing the mold.

• Journal of Sensor Science and Technology
• /
• v.16 no.6
• /
• pp.419-427
• /
• 2007

Single crystal $ZnIn_{2}S_{4}$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $450^{\circ}C$ with the hot wall epitaxy (HWE) system by evaporating the polycrystal source of $ZnIn_{2}S_{4}$ at $610^{\circ}C$ prepared from horizontal electric furnace. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $ZnIn_{2}S_{4}$ thin films measured with Hall effect by van der Pauw method are $8.51{\times}10^{17}\;electron/cm^{-3}$, $291{\;}cm^{2}/v-s$ at 293 K, respectively. The photocurrent and the absorption spectra of $ZnIn_{2}S_{4}$/SI(Semi-Insulated) GaAs(100) are measured ranging from 293 K to 10 K. The temperature dependence of the energy band gap of the $ZnIn_{2}S_{4}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)$=2.9514 eV. ($7.24{\times}10^{-4}\;eV/K$)$T^{2}$/(T+489 K). Using the photocurrent spectra and the Hopfield quasicubic model, the crystal field energy(${\Delta}cr$) and the spin-orbit splitting energy(${\Delta}so$) for the valence band of the $ZnIn_{2}S_{4}$ have been estimated to be 167.8 meV and 14.8 meV at 10 K, respectively. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}$-, $B_{1}$-, and $C_{41}$-exciton peaks.

• Transactions of Materials Processing
• /
• v.24 no.1
• /
• pp.44-51
• /
• 2015

The current study seeks to examine the effects of V and C additions on the mechanical and low thermal expansion properties of a high strength invar base alloy. The base alloy (Fe-36%Ni-0.9%Co-2.75%Mo-0.7Cr-0.23Mn-0.17Si-0.3%C, wt.%) contains $Mo_2C$ carbides, which form as the main precipitate. In contrast, alloys with additions of 0.4%V+0.3%C (alloy A) or 0.4%V+0.45%C (alloy B) contain $Mo_2C$+[V, Mo]C carbides. The average thermal expansion coefficients of these high strength invar based alloys were measured in the range of $5.16{\sim}5.43{\mu}m/m{\cdot}^{\circ}C$ for temperatures of $15{\sim}230^{\circ}C$. Moreover, alloy B showed lower thermal expansion coefficient than the other alloys in this temperature range. For the mechanical properties, the [V, Mo]C improved hardness and strengths(Y.S. and T.S.) of the high strength invar base alloy. T.S.(tensile strength) and Y.S.(yield strength) of hot forged alloy B specimen were measured at 844.6MPa and 518.0MPa, respectively. The tensile fractography of alloy B exhibited a ductile transgranular fracture mode and voids were initiated between the [V, Mo]C particles and the matrix. Superior properties of high strength and low thermal expansion coefficient can be obtained by [V, Mo]C precipitation in alloy B with the addition of 0.4%V and 0.45%C.

• Journal of Microbiology
• /
• v.43 no.6
• /
• pp.537-545
• /
• 2005

Even though neutralizing antibodies against the Hantaan virus (HTNV) has been proven to be critical against viral infections, the cellular immune responses to HTNV are also assumed to be important for viral clearance. In this report, we have examined the cellular and humoral immune responses against the HTNV nucleocapsid protein (NP) elicited by virus infection or DNA vaccination. To examine the cellular immune response against HTNV NP, we used $H-2K^b$ restricted T-cell epitopes of NP. The NP-specific $CD8^+$ T cell response was analyzed using a $^{51}Cr-release$ assay, intracellular cytokine staining assay, enzyme-linked immunospot assay and tetramer binding assay in C57BL/6 mice infected with HTNV. Using these methods, we found that HTNV infection elicited a strong NP-specific $CD8^+$ T cell response at eight days after infection. We also found that several different methods to check the NP-specific $CD8^+$ T cell response showed a very high correlation among analysis. In the case of DNA vaccination by plasmid encoding nucleocapsid gene, the NP-specific antibody response was elicited $2\~4$ weeks after immunization and maximized at $6\~8$ weeks. NP-specific $CD8^+$ T cell response reached its peak 3 weeks after immunization. In a challenge test with the recombinant vaccinia virus expressing NP (rVV-HTNV-N), the rVV-HTNV-N titers in DNA vaccinated mice were decreased about 100-fold compared to the negative control mice.

• Journal of Korean Public Health Nursing
• /
• v.16 no.1
• /
• pp.190-200
• /
• 2002

This study was carried out to investigate and analyze TSP of the PC rooms. The concentration of the total suspended particulate and heavy metals contained in the total suspended particulate of the 15 PC rooms located in one local city were measured. The statistical correlation coefficients between the total suspended particulate and factors of the indoor condition (number of fan or size of pc room, illumination), between the heavy metals and factors of the indoor condition were studied. The results are as follows: 1. The factors of the indoor condition of the 15 PC rooms are as follows. Average illumination was 24 luxes. Average number of computers installed were 37. Average number of the fans was 7. and the size of investigated PC rooms was $139.94m^2$. 2. The mean age of the subjects was 21.8 years old. they $(51.5\%)$ used the 15 pc rooms for fewer than 2 hours per one day. 3. The mean concentration of total suspended particulate (TSP) is lower in the evening ${139.085\;(2.462)\;{\mu}g/m^3}$ than the night ${166.216(2.609){\mu}g/m^3}$. 4. The mean concentration of total suspended particulate was industrial work area) residential area) commercial area. 5. The distribution of heavy metals were indicated as Zn>Cr>Pb>Cd in the indoor air at PC rooms. and the concentration rate of Zn was the highest among heavy metals. but this increase didn't show any relationship with many factors of indoor condition (number of fan or size of pc room, lighting) 6. The concentration of TSP & heavy metals didn't have any relationship between the factors of indoor environment (number of fans, size of pc room, lighting).

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2018.04a
• /
• pp.48-48
• /
• 2018

본 연구는 우리나라 산림습원의 식물종 다양성을 보존하기 위한 일환으로 충북지역 산림습원 34개소에 분포하는 관속식물 현황을 파악하고자 수행하였다. 현지조사는 2017년 4월부터 10월까지 7개월 동안 수행하였다. 조사 결과 충북지역 산림습원에 분포하는 관속식물은 총 98과 312속 502종 5아종 71변종 587분류군으로 충북지역 전체 식물상 약 1,241분류군의(국립수목원 한국관속식물분포도, 2016) 47.3%로 나타났다. 습지에 출현하는 빈도에(수생태사업단 우리나라습지생태계 관속식물의 유형분류, 2012) 따라 구분한 결과 절대습지식물은 물꽈리아재비, 큰고양이수염, 통발, 벗풀, 올챙이고랭이, 택사 등 27분류군, 임의습지식물은 버드나무, 쉽싸리, 물억새, 이삭사초, 부처꽃, 비녀골풀, 솔발울고랭이, 양뿔사초, 진퍼리새 등 51분류군이다. 또한 습원과 육지에서 동시 출현하는 양생식물은 모시물통이, 왕미꾸리광이, 물양지꽃, 좀고추나물, 감자개발나물, 참삿갓사초 등 29분류군, 임의육상식물은 쇠뜨기, 고비, 고추나물, 방동사니, 강계큰물통이, 오리새, 처녀바디 등 25분류군, 절대육상식물은 애기탑꽃, 좀진고사리, 옥잠난초, 물들메나무, 뻐국나리, 진범, 범꼬리 등 88분류군으로 확인되었다. 특히 절대습지식물 중 애기물꽈리아재비, 큰고양이수염, 개쉽싸리, 통발, 송이고랭이, 올방개아재비, 흰고양이수염 등 11분류군은 충북내에서 새롭게 분포가 확인되었다. 산림청 지정 희귀식물은 양뿔사초(CR), 애기물꽈리아재비(VU), 통발(VU) 등 16분류군, 한국특산식물은 키버들, 강계큰물통이, 물들메나무, 넓은잎각시붓꽃 등 19분류군이다. 식물구계학적 특정식물로는 V등급 통발 등 3분류군, IV등급 왜방풍 등 9분류군, III등급 음양고비 등 18분류군, II등급 12분류군, I등급 30분류군이 확인되었다. 외래식물은 큰닭의덩굴, 미국자리공, 붉은서나물 등 27분류군으로 나타났다.

• Imaging Science in Dentistry
• /
• v.40 no.4
• /
• pp.165-169
• /
• 2010

Purpose : To survey the radiographic examination protocol for lateral cephalometric radiographic examinations and to measure their patient doses in Korea and to compare the dose according to the size of hospital, the type of image receptor system, and the installation duration. Materials and Methods : The radiographic examination protocols (kVp, mA, and exposure time) for lateral cephalometric radiography were surveyed with 61 cephalometric radiographic equipments and their patient dose-area product (DAP) measured with a DAP meter (DIAMENTOR M4-KDK, PTW, Freiburg, Germany) for 51 cephalometric radiographic equipments. The radiographic examination protocols and patient doses were compared according to the size of hospital (university dental hospital, dental hospital, and dental clinic), the type of image receptor system (film-based, DR and CR type) and the installation duration, respectively. SPSS 12.0.1 for Windows (SPSS Inc., Chicago, USA) was used for independent t-test and ANOVA test. Results : The average protocols were 77.0 kVp, 12.7 mA, 6.2 second for cephalometric radiography. The average patient dose (DAP) was $128.0mGy\;cm^2$ and 3rd quartile dose (DAP) $161.1mGy\;cm^2$ for cephalometric radiography for adult male. There was no statistically significant difference at average patient DAP according to the size of hospital, the type of image receptor system, and the installation duration, repectively. Conclusion : The average patient dose was $128.0mGy\;cm^2$ and the third quartile patient dose $161.1mGy\;cm^2$ for lateral cephalometric radiography for adult male in Korea.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.15 no.1
• /
• pp.75-83
• /
• 1985

Bitewing and periapical radiographic techniques are used in clinical and epidemiological studies to assess crestal alveolar bone levels. The purpose of the present study investigated relationships between these techniques by assessing alveolar crest location at the same site. Bitewing and periapical radiographs were available from posterior quadrants of 120 subjects. The distance from cemento-enamel junction to the alveolar crest (CEJ -CR) was measured for each proximal surface from the distal of the cuspid to the distal of the second molar. Data were arranged according to the proximal surface examined, and bitewing and periapical measurements were compared using paired tests. The obtained results were as follows; 1. In maxilla, a significant t ratio with a P value of 0.05 or less was reached for 78% and in mandible reached for 39%. 2. Pearson correlations were calculated 32 surfaces (89%) had values below 0.70 and so, data obtained by these techniques can not be used interchangeably on an individual or group basis. 3. In situations where the periapical measure was greater than the bitewing, it ranged up to 20.7% greater with a mean 9.8%. Where the bitewing was greater than periapical, it ranged up to 51. 9% greater, with a mean 18.2%. 4. The percentage difference was greater in maxillary posterior areas than in mandibular molar, premolar areas. A lower prevalence of significant differences was attributed to relatively more simple root and favorable radiographic conditions in mandibular molar and premolar areas. 5. The anatomical limitations imposed on periapical radiographic technique, most often result in somewhat foreshortened radiographic images. This situation would tend to be accentuated by the anatomical restrictions of the hard palate. 6. Consequently, since the significant differences frequently exist between measurements obtained from bitewing and periapical techniques, it is important to define which technique is used.

• Journal of Embryo Transfer
• /
• v.29 no.3
• /
• pp.229-234
• /
• 2014

The aim of the present study was to compare two different serum-free media, modified synthetic oviduct fluid (mSOF) and modified potassium simplex optimization medium (mKSOM) containing 20% RD (RPMI1640 + DMEM, 1:1 v/v) (RD-mKSOM), for in vitro culture (IVC) of bovine embryos. After in vitro maturation and fertilization, the presumptive zygotes were cultured in two different serum-free conditions for 7 days and 9 days to evaluate blastocyst formation and hatching, respectively. Serum supplemented conventional CR2 medium was used as control. After 7 day of culture, there was no significant difference in cleavage and blastocyst formation rates among three groups (mSOF, 59.3 and 30.1%; RD-mKSOM, 65.0 and 41.5%; control, 51.6 and 38.0%, respectively). Hatching rate was significantly higher in control (69.0%) than other experimental groups (mSOF, 22.0%; RD-mKSOM, 39.5%) (P<0.0001 and P<0.001, respectively). Although both serum-free conditions showed lower hatching rates than serum-added control, in serum-free groups, RD-mKSOM showed significantly higher hatching rate than mSOF (P<0.001). In addition, one-step using RD-mKSOM may facilitate IVC procedure than two-step culture system. In conclusion, the results indicate that one-step RD-mKSOM is more suitable defined culture system for IVC of bovine embryos than two-step mSOF.