• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.169-169
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• 2008

To keep pace with scaling trends of CMOS technologies, high-k metal oxides are to be introduced. Due to their high permittivity, high-k materials can achieve the required capacitance with stacks of higher physical thickness to reduce the leakage current through the scaled gate oxide, which make it become much more promising materials to instead of $SiO_2$. As further studying on high-k, an understanding of the relation between the etch characteristics of high-k dielectric materials and plasma properties is required for the low damaged removal process to match standard processing procedure. There are some reports on the dry etching of different high-k materials in ICP and ECR plasma with various plasma parameters, such as different gas combinations ($Cl_2$, $Cl_2/BCl_3$, $Cl_2$/Ar, $SF_6$/Ar, and $CH_4/H_2$/Ar etc). Understanding of the complex behavior of particles at surfaces requires detailed knowledge of both macroscopic and microscopic processes that take place; also certain processes depend critically on temperature and gas pressure. The choice of $BCl_3$ as the chemically active gas results from the fact that it is widely used for the etching o the materials covered by the native oxides due to the effective extraction of oxygen in the form of $BCl_xO_y$ compounds. In this study, the surface reactions and the etch rate of $Al_2O_3$ films in $BCl_3/Cl_2$/Ar plasma were investigated in an inductively coupled plasma(ICP) reactor in terms of the gas mixing ratio, RF power, DC bias and chamber pressure. The variations of relative volume densities for the particles were measured with optical emission spectroscopy (OES). The surface imagination was measured by AFM and SEM. The chemical states of film was investigated using X-ray photoelectron spectroscopy (XPS), which confirmed the existence of nonvolatile etch byproducts.

• Journal of the Korean Magnetics Society
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• v.18 no.1
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• pp.39-42
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• 2008

[ $AB_2X_4$ ](A, B=Transition Metal, X=O, S, Se) are cubic spinel normal ferrimagnets, in which M ions occupy the tetrahedral sites and Cr ions occupy the octahedral sites. Recently, they have been investigated for behaviour of B site ions and A-B interaction. Polycrystalline $[Co_{0.9}Zn_{0.1}]_A[Cr_{1.98}{^{57}Fe_{0.02}}]_BO_4$ compound was prepared by wet-chemical process. The ferrimagnetic transition was observed around 90K. $M\"{o}ssbauer$ absorption spectra at 4.2K show that the well-developed two sextets are superposed with small difference in hyperfine fields($H_{hf}$). The hyperfine fields of $CoCr_{1.98}{^{57}Fe_{0.02}}O_4$ and $Co_{0.9}Zn_{0.1}Cr_{1.98}{^{57}Fe_{0.02}}O_4$ were determined to be 488, 478 kOe and 486, 468 kOe, respectively. We notice that the one of the magnetic hyperfine field values changes with Zn ion substitution. These results suggest the incommensurate states and spin-reorientation temperature($T_S=18K$) changes with Zn ions substitution below spin-reorientation temperature($T_S=28K$) of $CoCr_{1.98}{^{57}Fe_{0.02}}O_4$

• Journal of The Korean Society of Clinical Toxicology
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• v.2 no.1
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• pp.41-44
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• 2004

With a recent well-being boom, our interest in chemical-free vegetables is also increasing. So, some people are trying to take in wild plants chosen by themselves. However, others often come to their rescue in an emergency department after eating them, caused by their misunderstanding poisonous herbs as edible vegetables. We have ever seen two persons carried into the emergency department with bradycardia and shock incurred by his intake by confusion between Caltha palustris and Ligularia fischeri lately. There were symptoms such as epigastric pain, nausea, vomiting and so on in their cases, and the symptoms of bradycardia and hypotension continued. Owing to sustained bradycardia and hypotension states, we applied a dopamine to a patient, and then the in-patient left the hospital two days later. We presumed the cause of the two symptoms appeared in two cases to be a saponin in Caltha palustris. For that reason, if someone has the bradycardia and hypotension symptoms from an unknown cause after taking in wild plants, they have to consider a toxication by the Caltha palustris. Therefore, this paper focused on the issue that unexpected poisoning would have to be prevented by studying about wild plants much more and informing the toxic risk from the plants.

• Journal of Science and Technology Studies
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• v.12 no.1
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• pp.1-43
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• 2012

This paper examines the American Civil Liberties Union(ACLU)'s recent legal challenge on patents held by Myriad Genetics on two genes (BRCA1 and BRCA2) associated with a high risk of breast and ovarian cancer. Instead of analyzing the ACLU's objections to the BRCA patents in terms of its legal technicalities and normative ethical principles, this paper seeks to situate this legal case in the broader historical context of the shifting understanding of the relationship between private ownership, economic development, and the public interest in academic sciences. This paper first briefly chronicles a series of scientific developments and key legal decisions involving patenting of life forms, including genetically engineered micro-organisms animals and biological materials of human origins like cell cultures and genes, that led to the US Patent and Trademark Office(USPTO)'s official guidelines on human gene patenting in 2001. At another level, this paper analyzes the expansion of the scope of intellectual property rights in the life sciences in terms of shifting economic and legal assumptions about public knowledge and its role for economic development in the 1970s. I then show how these economic, legal, and ethical ideas that linked private ownership and the public interest have been challenged from the 1990s, calling for revisions in intellectual property laws regarding a wide array of life forms. The tragedy of the anticommons in human gene patenting, according to ACLU, has severely undermined creative scientific activities, medical innovations, access to health care and rights to life among cancer patient groups. ACLU's objection to human gene patenting on several US-constitutional grounds in turn suggests issues regarding intellectual property are critically linked to vital issues pertinent to the creative communities in arts and sciences, such as free exchange of ideas, censorship and monopoly, and free expression and piracy etc.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.559-563
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• 2015

Monitor of All-sky X-ray Image (MAXI) is a Japanese X-ray all-sky surveyer mounted on the International Space Station (ISS). It has been scanning the whole sky since 2009 during every 92-minute ISS rotation. X-ray transients are quickly found by the real-time nova-search program. As a result, MAXI has issued 133 Astronomer's Telegrams and 44 Gamma-ray burst Coordinated Networks so far. MAXI has discovered six new black holes (BH) in 4.5 years. Long-term behaviors of the MAXI BHs can be classified into two types by their outbursts; a fast-rise exponential-decay type and a fast-rise flat-top one. The slit camera is suitable for accumulating data over a long time. MAXI issued a 37-month catalog containing 500 sources above a ~0.6 mCrab detection limit at 4-10 keV in the region ${\mid}{b}{\mid}$ > $10^{\circ}$. The SSC instrument utilizing an X-ray CCD has detected diffuse soft X-rays extending over a large solid angle, such as the Cygnus super bubble. MAXI/SSC has also detcted a Ne emission line from the rapid soft X-ray nova MAXI J0158-744. The overall shapes of outbursts in Be X-ray binaries (BeXRB) are precisely observed with MAXI/GSC. BeXRB have two kinds of outbursts, a normal outburst and a giant one. The peak dates of the subsequent giant outbursts of A0535+26 repeated with a different period than the orbital one. The Be stellar disk is considered to either have a precession motion or a distorted shape. The long-term behaviors of low-mass X-ray binaries (LMXB) containing weakly magnetized neutron stars are investigated. Transient LMXBs (Aql X-1 and 4U 1608-52) repeated outbursts every 200-1000 days, which is understood by the limit-cycle of hydrogen ionization states in the outer accretion disk. A third state (very dim state) in Aql X-1 and 4U 1608-52 was interpreted as the propeller effect in the unified picture of LMXB. Cir X-1 is a peculiar source in the sense that its long-term behavior is not like typical LMXBs. The luminosity sometimes decreases suddenly at periastron. It might be explained by the stripping of the outer accretion disk by a clumpy stellar wind. MAXI observed 64 large flares from 22 active stars (RS CVns, dMe stars, Argol types, young stellar objects) over 4 years. The total energies are $10^{34}-10^{36}$ erg $s^{-1}$. Since MAXI can measure the spectrum (temperature and emission measure), we can estimate the size of the plasma and the magnetic fields. The size sometimes exceeds the size of the star. The magnetic field is in the range of 10-100 gauss, which is a typical value for solar flares.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.141-146
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• 1988

Dwarf ginseng (Panax trifolius L.) is a member of the ginseng family (Araliaceae). which is indigenous to North America and is distributed from Southern Canada to the Northern United States. In total. nine compounds were isolated from the leaves of Dwarf gineng. Of these. four were identified as flavonoids and five were found to be ginsenosides. Two of the flavonoids were identified to be kaempferol-3. 7-dirhamnoside and kaempferol-3-gluco-7-rhamnoside. Four of the ginsenosides were identified as notoginsenoside-Fe. ginsenoside-Rd. ginsenoside-Rc and $ginsenoside-Rb_1$ The common aglycone of these ginsenosides was shown to be (20S)-protopanaxadiol. The identification of flavonoids and ginsenosides from the root. stem. leaf. flower and fruit of Dwarf ginseng was detected by Two-Dimensional Thin-Layer Chromatography (2D-TLC) and High Performance Liquid Chromatography (HPLC). The quantitation of flavonoids and ginsenosides from the root. stem. leaf. flower and fruit of Dwarf ginseng and related species such as Korean gineng (Panax ginseng C.A. Meyer) and American ginseng (Panax quinquefolium L.) was analyzed by HPLC only. Three flavonoids (Kaempferol derivatives) labelled compound 1 $(10.8\%)$, compound 3 ($2.8\%$), and compound 4 ($8.4\%)$ were found in the root of Dwarf ginseng but not found in the roots of Korean ginseng and American ginseng. This is the first time that flavonoids have been found and identified in roots of the ginseng family (Araliaceae).

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.411-418
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• 2004

Mercury, one of the most diffused and hazardous organ-specific environmental contaminants, exists in a wide variety of physical and chemical states. The murcury with the nature which evaporates easily can cause an acute or chronic mercury poisoning to workers at mercury-handling workplaces. Although many studies indicate that mercury induces a deleterious damage, little has been reported from the investigations of mercury effects at surrounding levels in living things. The purpose of this study was to evaluate the biological effects of mercury chloride and ionizing radiation. Prepubertal male F344 rats were administered mercury chloride in drinking water throughout the experimental period or were given wholebody irradiation with a dose of 6.5 Gy. The amount changed of body weight during the experimental period showed a 4.9% rise in the mercury-treated group and 14.4% decline in the irradiated group compared with the level of the control group. The results of hematological analysis (red blood cells, white blood cells, hemoglobin, and hematocrit) indicated the differential effects of mercury chloride and ionizing radiation. However the concentration of cortisol as assessed by radioimmunoassay increased in both of the groups. Relative expressions of mRNA related to mitochondrion-mediated apoptosis were investigated using semiquantitative reverse transcription polymerase chain reaction on gonad and urinary organs of the experimental groups. While the expression of Bcl-2 mRNA exhibited different patterns depending on the organs or the experimental groups, both of the experimental groups showed a conspicuous expressions of Bax mRNA. In conclusion, the target organ of mercury chloride seems to be a urinary organ and the pattern of damage induced by mercury chloride differs from that by ionizing radiation.

• Analytical Science and Technology
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• v.16 no.3
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• pp.249-260
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• 2003

The disinfection of drinking water to control microbial contaminants results in the formation of secondary chemical contaminants, DBPs (disinfection by-products). It was studied the formation pattern of DBPs in drinking raw water after hypochlorite, chlorine disinfectant, was added in this study. It was determined TOC (total organic carbon), residual chlorine, turbidity and DBPs in raw water from Han-river during 1~14 days. Total DBPs was $101.3ng/m{\ell}$ (789.6 nM) after 7days and THMs (trihalomethanes) are the dominant portion of 69%. HAAs (haloacetic acids) and chloral hydrate were determined 19% and 10% respectively, and HANs (haloacetonitriles), HKs (haloketones) and chloropicrin were analyzed in trace level. Chloroform occupied about 89% in total THMs in concentration of $61.5ng/m{\ell}$, 95% of HANs was DCAN (dichloroacetonitrile) in $0.72ng/m{\ell}$, 50% of HAAs was TCAA (trichloroacetic acid). On the study of relationship in formation among the DBPs, HANs forms with THMs competitively to the point of the concentration of $40ng/m{\ell}$ of THMs. For HAAs, it did not show the prominent tendency. But it was observed that the compounds of large oxidation state are formed at first, and becomes to the compounds of low oxidation states.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.186-186
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• 2000

After LeComber et al. reported the first amorphous hydrogenated silicon (a-Si: H) TFT, many laboratories started the development of an active matrix LCDs using a-Si:H TFTs formed on glass substrate. With increasing the display area and pixel density of TFT-LCD, however, high mobility TFTs are required for pixel driver of TF-LCD in order to shorten the charging time of the pixel electrodes. The most important of these drawbacks is a-Si's electron mobiliy, which is the speed at which electrons can move through each transistor. The problem of low carier mobility for the a-Si:H TFTs can be overcome by introducing polycrystalline silicon (poly-Si) thin film instead of a-Si:H as a semiconductor layer of TFTs. Therefore, poly-Si has gained increasing interest and has been investigated by many researchers. Recnetly, fabrication of such poly-Si TFT-LCD panels with VGA pixel size and monolithic drivers has been reported, . Especially, fabricating poly-Si TFTs at a temperature mach lower than the strain point of glass is needed in order to have high mobility TFTs on large-size glass substrate, and the monolithic drivers will reduce the cost of TFT-LCDs. The conventional methods to fabricate poly-Si films are low pressure chemical vapor deposition (LPCVD0 as well as solid phase crystallization (SPC), pulsed rapid thermal annealing(PRTA), and eximer laser annealing (ELA). However, these methods have some disadvantages such as high deposition temperature over $600^{\circ}C$, small grain size (<50nm), poor crystallinity, and high grain boundary states. Therefore the low temperature and large area processes using a cheap glass substrate are impossible because of high temperature process. In this study, therefore, we have deposited poly-Si thin films on si(100) and glass substrates at growth temperature of below 40$0^{\circ}C$ using newly developed high rate magnetron sputtering method. To improve the sputtering yield and the growth rate, a high power (10~30 W/cm2) sputtering source with unbalanced magnetron and Si ion extraction grid was designed and constructed based on the results of computer simulation. The maximum deposition rate could be reached to be 0.35$\mu$m/min due to a high ion bombardment. This is 5 times higher than that of conventional sputtering method, and the sputtering yield was also increased up to 80%. The best film was obtained on Si(100) using Si ion extraction grid under 9.0$\times$10-3Torr of working pressure and 11 W/cm2 of the target power density. The electron mobility of the poly-si film grown on Si(100) at 40$0^{\circ}C$ with ion extraction grid shows 96 cm2/V sec. During sputtering, moreover, the characteristics of si source were also analyzed with in situ Langmuir probe method and optical emission spectroscopy.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.7-8
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• 2010

The surface conductive layer (SCL) of chemical vapor deposition (CVD) diamonds has attracting much interest. However, neither photoemission electron microscopic (PEEM) nor micro-spectroscopic (PEEMS) information is available so far. Since SCL retains in an ultra-high vacuum (UHV) condition, PEEM or PEEMS study will give an insight of SCL, which is the subject of the present study. The sample was made on a Ib-type HTHP diamond (001) substrate by non-doping CVD growthin a DC-plasma deposition chamber. The SCL properties of the sample in air were; a few tens K/Sq. in sheet resistance, ${\sim}180\;cm^2/vs$ in Hall mobility, ${\sim}2{\times}10^{12}/cm^2$ in carrier concentration. The root-square-mean surface roughness (Rq) of the sample was ~0.2nm as checked by AFM. A $2{\times}1$ LEED pattern and a sheet resistance of several hundreds K/Sq. in UHV were checked in a UHV chamber with an in-situ resist-meter [1]. The sample was then installed in a commercial PEEM/S apparatus (Omicron FOCUS IS-PEEM) which was composed of electro-static-lens optics together with an electron energy-analyzer. The presence of SCL was regularly monitored by measuring resistance between two electrodes (colloidal graphite) pasted on the two ends of sample surface. Figure 1 shows two PEEM images of a same area of the sample; a) is excited with a Hg-lamp and b) with a Xe-lamp. The maximum photon energy of the Hg-lamp is ~4.9 eV which is smaller that the band gap energy ($E_G=5.5\;eV$) of diamond and the maximum photon energy of the Xe-lamp is ~6.2 eV which is larger than $E_G$. The image that appear with the Hg-lamp can be due to photo-excitation to unoccupied states of the hydrogen-terminated negative electron affinity (NEA) diamond surface [2]. Secondary electron energy distribution of the white background of Figs.1a) and b) indeed shows that the whole surface is NEA except a large black dot on the upper center. However, Figs.1a) and 1b) show several features that are qualitatively different from each other. Some of the differences are the followings: the two main dark lines A and B in Fig.1b) are not at all obvious and the white lines B and C in Fig.1b) appear to be dark lines in Fig.1a). A PEEMS analysis of secondary electron energy distribution showed that all of the features A-D have negative electron affinity with marginal differences among them. These differences can be attributed to differences in the details of energy band bending underneath the surface present in SCL [3].