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BACKGROUND AND PURPOSE: The long scan time of MR imaging is a major drawback limiting its clinical use in neuroimaging; therefore, we aimed to investigate the clinical feasibility of a 1-minute full-brain MR imaging using a multicontrast EPI sequence on a different MR imaging scanner than the ones previously reported. MATERIALS AND METHODS: We retrospectively reviewed the records of 146 patients who underwent a multicontrast EPI sequence, including T1-FLAIR, T2-FLAIR, T2WI, DWI, and T2*WI sequences. Two attending neuroradiologists assessed the image quality of each sequence to compare the multicontrast EPI sequence with routine MR imaging protocols. We used the Wilcoxon signed rank test and McNemar test to compare the 2 MR imaging protocols. RESULTS: The multicontrast EPI sequence generally showed sufficient image quality of >2 points using a 4-point assessment scale. Regarding image quality and susceptibility artifacts, there was no significant difference between the multicontrast EPI sequence DWI and routine DWI (P > .05), attesting to noninferiority of the multicontrast EPI, whereas there were significant differences in the other 4 sequences between the 2 MR imaging protocols. CONCLUSIONS: The multicontrast EPI sequence showed sufficient image quality for clinical use with a shorter scan time; however, it was limited by inferior image quality and frequent susceptibility artifacts compared with routine brain MR imaging. Therefore, the multicontrast EPI sequence cannot completely replace the routine MR imaging protocol at present; however, it may be a feasible option in specific clinical situations such as screening, time-critical diseases or for use with patients prone to motion.

BACKGROUND AND PURPOSE: Conventional MR imaging techniques cannot produce optimal images of bone structures because bone has little water and a very short T2 life span. The aim of this study was to investigate the clinical feasibility of skull MR imaging using the zero TE sequence in patients with head trauma by assessing its diagnostic image quality and quantitative measurement compared with CT images. MATERIALS AND METHODS: Thirteen enrolled patients with head trauma were assessed using brain CT and skull MR imaging. Image quality was graded on a 5-point Likert scale to compare the 2 modalities. To evaluate quantitative analyses between the 2 imaging modalities, we measured skull thickness and normalized bone tissue signal. Interobserver reliability was assessed using weighted κ statistics and the intraclass correlation coefficient. RESULTS: Both imaging techniques clearly depicted skull fractures in all 13 patients. The mean scores for skull MR imaging and CT were 4.65 ± 0.56 and 4.73 ± 0.45 (P = .157), respectively, with substantial interobserver agreement (P < .05). The 2 imaging modalities showed no difference in skull thickness (P = .092) and had good correlation (r(2) = 0.997). The mean value of normalized bone tissue signal among the 3 layers of the skull was relatively consistent (P = .401) with high interobserver agreement (P < .001). CONCLUSIONS: Zero TE skull MR imaging has diagnostic image quality comparable with that of CT images. It also provides consistent results on the quantitative measurement of cortical bone with CT images.

The previous two-dimensional non-linear tidal model of the East China Sea (Chung, 1986) has been further refined to resolve the flow over the continental shelf in more detail. The mesh resolution of the present finite-difference grid system used is 4 minutes latitude by 5 minutes longitude over the entire shelf. The developed fine grid two-dimensional model was utilized to reproduce the M{sub 2} tide and M{sub 4} tide for the East China Sea continental shelf. There is general agreement between the model results and the current observation made in the Eastern Yellow Sea, which supports the calculated tidal regime over the shelf. Some preliminary results on maximum bottom stress and tidally-induced residual current were also examined and discussed.

This study identified 59 SNPs significantly (P

Background To investigate the feasibility of virtual monoenergetic images (VMIs) derived from a dual-layer detector spectral CT (SDCT) in patients with breast cancer by assessing tumor conspicuity in comparison with conventional images (CI) and to correlate tumor conspicuity on VMIS with prognostic biomarkers. Methods 64 patients with pathologically proven benign or breast cancers (14 benign lesions and 65 breast cancers) underwent arterial and 90s delayed phase scan on a SDCT for tumor staging between June 2016 and May 2018. CI were reconstructed at 120kVp, and VMI at 40 keV (VMI40). A retrospective spectral data analysis was performed to assess the regions of interest by using CI and VMI40 on arterial and delayed images (CIART, VMI40ART, CIDE, and VMI40DE). Two radiologists independently reviewed the 4 image sets for the conspicuity score of breast lesions. For quantitative analysis, measurement of Hounsfield units (HU) of breast lesions on VMI40ART and VMI40DE was performed. Receiver operating characteristic (ROC) analysis was performed. Estrogen receptor (ER), human epidermal growth factor receptor 2 (HER2), and Ki67 level were evaluated using histopathology. Statistically, conspicuity score and mean HU of malignant lesions were correlated with histological characteristics. Results The mean conspicuity score of malignant lesions was significantly higher compared with that of benign lesions in all image sets (P Conclusions VMI40DE is feasible to diagnose breast cancers with higher conspicuity score and better contrast enhancement compared with VMI40ART. Moreover, VMI40ART may serve as additional predictors of a poor breast cancer prognosis. Legal entity responsible for the study The author. Funding Has not received any funding. Disclosure The author has declared no conflicts of interest.

In this study, springback amounts of an S-rail are quantitatively compared according to the hardening model using a finite element simulation for the stamping process with high strength steels. For comparison of the hardening models, two types of hardening models were investigated. The two models were isotropic hardening and kinematic hardening. For the analysis with kinematic hardening, the Yoshida-Uemori model was selected. Five kinds of springback modes were measured at designated sections and a comparison was made between the experiment and the analyses with two types of hardening models. The analysis results show that the springback in the flange and the wall curl are predicted more accurately with a kinematic hardening model.

Quantitative trait loci (QTL) associated with fat deposition traits in pigs are important gene positions in a chromosome that influence meat quality of pork. For QTL study, a three generation resource population was constructed from a cross between Korean native boars and Landrace sows. A total of 240 F2 animals from intercross of F1 were produced. 80 microsatellite markers covering chromosomes 1 to 10 were selected to genotype the resource population. Intervals between adjacent markers were approximately 19 cM. Linkage analysis was performed using CRIMAP software version 2.4 with a FIXED option to obtain the map distances. For QTL analysis, the public web-based software, QTL express (http://www.qtl.cap.ed.ac.uk) was used. Two significant and two suggestive QTL were identified on SSC 6, 7, and 8 as affecting body fat and IMF traits. For QTL affecting IMF, the most significant association was detected between marker sw71 and sw1881 on SSC 6, and a suggestive QTL was identified between sw268 and sw205 on SSC8. These QTL accounted for 26.58% and 12.31% of the phenotypic variance, respectively. A significant QTL affecting IMF was detected at position 105 cM between markers sw71 and sw1881 on SSC 6.

This study investigates the effect of welding condition according to mechanical properties of pure titanium and presents the optimum welding condition through the evaluation about the weldability of pure titanium by the welding conditions such as the welding pass, the amount of shielded gas and the welding time interval. In order to find out optimum welding condition by the mechanical properties of pure titanium, the annealed pure titanium of the ASTM B265 grade 2 is selected as a specimen and is classified by several welding conditions. And then, the experiments performed the test of tension, impact and hardness under the welding condition, respectively. The experimental result revealed that the specimen of 4-pass has the highest tensile strength in case of the welding pass condition. And, in case of the shielding gas condition, the tensile strength and elongation occurs the highest to the specimen of 25 l/min. The hardness value at the HAZ (heated affected zone) is higher than that for the WMZ (welding metal zone) and reveals almost the constant value more and more distance at the HAZ. Also, the impact absorption energy shows the high tendency by an increase in the number of pass.

This study was conducted to analyze the genetic characteristics of Korean Native Pigs(KNP), and to establish an individual identification system comprising many microsatellite markers located on different pig autosomes. Genotype data from 13 microsatellites typed in 446 animals was used to determine the validation of a method of individual identification in 4 KNP. A total of 112 alleles of the 13 microsatellites were detected and average heterozygosities(polymorphic information content) ranged from 0.286(0.423) to 0.686(0.796) in this study. Comparing the pattern of allele frequency among the KNP, Yorkshire, Landrace and Duroc breeds, there was specific differentiation between populations at multi-allelic loci. The cumulative power of discrimination(CPD) was 99.999% by including 10 microsatellite loci for the individual identification system. The probability that two different individuals incidentally have same genotype was estimated to be . The system employing these 10 markers therefore proved to be applicable to the individual identification of KNP.

This study was carried out to recover phosphorus in animal wastewater using a magnesium source. , as a magnesium source, was shown a SP (soluble phosphorus) recovery rate of 98% in both the aeration and the NaOH tests to adjust pH around 8.5. In case of MgO, the recovery rate of SP were 88% with the aeration and 58% with the NaOH. In case of ammonia nitrogen recovery, was shown the recovery rate of 17% with aeration and 18% with NaOH. MgO was shown the ammonia recovery rate of 18% with aeration and 11% with NaOH. At low temperature of with the animal wastewater from piglet stall, the recovery rate of SP was shown 95% with NaOH and 92% with aeration using . The recovery rate of ammonia nitrogen was shown 9% with NaOH and 12% with aeration, respectively. It was observed that the pH can be raised by aeration. The reaction was completed within 5 minutes and the struvite cristal structure was formed and could be observed with an electronic microscope.

Ion implantations with energies less than 100 keV and current densities of 10 15 –10 18 ions/cm 2 were conducted to polymers, metals, and diamond gemstone. Physical and chemical phenomena and mechanical properties of the implanted materials were investigated. Single or mixed ions of N, He, C were implanted onto polyethylene terephtalate (PET) to see the surface hardening effects. Multiple ion-implantation resulted in more increase in the surface hardness than single ion implantation at the same ion energy and dose. Implantation of C + N ions increased the surface hardness by about three times as compared to implantation of N or C ions alone. XPS analysis showed that C–N compounds were formed when both N and C ions are implanted into PET, implying that hard particle formation by reactions between the implanted ions and/or between the implanted N ions and carbon in PET in addition to the cross linking may be the mechanism of this significant increase in hardness. Ion implantation with 70 keV N ions of >5 × 10 16 /cm 2 into the surface-polished stainless steel reduced the average surface roughness ( R a ) from 0.04 μm to 0.02 μm. The implanted nitrogen was detected up to at least 300 nm from the surface of the stainless steel as measured with Auger electron spectroscopy. X-ray photo-electron spectroscopy analysis showed that the implanted N formed mostly Cr 2 N without post irradiation annealing. Hardness depth profiles obtained with nano-indentation technique showed that the peak hardness of 14 Gpa formed at ≈50 nm depth from the N ion implanted surface was about at least 2 times higher than non-irradiated specimen. N ions were implanted into the diamond in order to change the optical band gap and then to change the emitted color. In spite of the restricted ion penetrated depth, uniform and vividly changed color was observed after heat treatment of the nitrogen-implanted diamond in the vacuum or inert gas atmosphere. The changed color appeared to be black. Chemical states of the implanted nitrogen were N–N and 4N-vacancy as characterized with FTIR. Band structure calculation shows that band gap of the diamond reduced by 25% after N doping.

Molecular genetic markers were used to detect chromosomal regions which contain economically important traits such as growth, carcass, and meat quality traits in pigs. A three generation resource population was constructed from a cross between Korean native boars and Landrace sows. A total of 240 F2 animals from intercross of F1 was produced. Phenotypic data on 17 traits, birth weight, body weights at 3, 5, 12, and 30 weeks of age, teat number, carcass weight, backfat thickness, body fat, backbone number, muscle pH, meat color, drip loss, cooking loss, water holding capacity, shear force, and intramuscular fat content were collected for F2 animals. Animals including grandparents (F0), parents (F1), and offspring (F2) were genotyped for 80 microsatellite markers covering from chromosome 1 to 10. Least squares regression interval mapping was used for quantitative trait loci (QTL) identification. Significance thresholds were determined by permutation tests. A total of 10 QTL were detected at 5% chromosome-wide significance levels for growth traits on SSCs 2, 4, 5, 6, and 8. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 11 : 1524-1528)

ADRP plays an important role in regulating lipid storage in various cells. We investigated the ADRP gene as a candidate gene for intramuscular fat deposition and marbling traits in pigs. A full-length transcript of porcine ADRP was cloned by RT-PCR and RACE. The porcine ADRP cDNA (1848 bp) contains a 1377-bp open reading frame, encoding a deduced protein of 459 amino acids, which has amino acid sequence identities of 89, 89, 82 and 81% with cattle, human, mouse and rat ADRP genes respectively. The genomic structure and sequence of the porcine ADRP were also analysed using a BAC clone of a Korean native pig. Pig ADRP comprises eight exons spanning approximately 13 kb and is located on chromosome 1 q2.3-q2.7 between microsatellite markers SW2185 and SW974. Several sequence variations were detected from nine different pig breeds. The biological role of this gene and the mapping localization indicated that the porcine ADRP is a possible candidate gene for fat deposition and marbling traits.

The action of riluzole, a neuroprotective drug, on cloned delayed rectifier K + channels (Kv1.5 and Kv3.1) was examined using the whole-cell patch-clamp technique. Riluzole reversibly inhibited Kv1.5 currents in a concentration-dependent manner with an IC 50 of 39.69±2.37μM. G-protein inhibitors (pertussis toxin and GDPβS) did not prevent this inhibition of riluzole on Kv1.5. No voltage-dependent inhibition by riluzole was found over the voltage range in which channels are fully activated. Riluzole shifted the steady-state inactivation curves of Kv1.5 in a hyperpolarizing direction in a concentration-dependent manner. It accelerated the deactivation kinetics of Kv1.5 in a concentration dependent-manner, but had no effect on the steady-state activation curve. Riluzole exhibited a use-independent inhibition of Kv1.5. The effects of riluzole on Kv3.1, the Shaw -type K + channel were also examined. Riluzole caused a concentration-dependent inhibition of Kv3.1 currents with an IC 50 of 120.98±9.74μM and also shifted the steady-state inactivation curve of Kv3.1 in the hyperpolarizing direction. Thus, riluzole inhibits both Kv1.5 and Kv3.1 currents in a concentration-dependent manner and interacts directly with Kv1.5 by preferentially binding to the inactivated and to the closed states of the channel.

As an experimental reference population, crosses between Korean native pig and Landraces were established and information on growth traits was recorded. Animals were genotyped for 24 microsatellite markers covering chromosomes 2, 6, and 7 for partial-genome scan to identify chromosomal regions that have effects on growth traits. quantitative trait loci (QTL) effects were estimated using interval mapping by the regression method under the line cross models with a test for imprinting effects. For test of presence of QTL, chromosome-wide and single position significance thresholds were estimated by permutation test and normal significance threshold for the imprinting test were derived. For tests against the Mendelian model, additive and dominance coefficients were permuted within individuals. Thresholds (5% chromosome-wide) against the no-QTL model for the analyzed traits ranged from 4.57 to 4.99 for the Mendelian model and from 4.14 to 4.67 for the imprinting model, respectively. Partial-genome scan revealed significant evidence for 4 QTL affecting growth traits, and 2 out of the 4 QTLs were imprinted. This study demonstrated that testing for imprinting should become a standard procedure to unravel the genetic control of multi-factorial traits. The models and tests developed in this study allowed the detection and evaluation of imprinted QTL. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 8 : 1087-1092)

The p -type Te doped Bi 0.5 Sb 1.5 Te 3 compounds were fabricated by powder extrusion in the temperature range 340–460 °C. The Seebeck coefficient, electrical resistivity and thermal conductivity were measured as a function of extrusion temperature to calculate the figure of merit. The highest bending strength (61.2 MPa) and the highest figure of merit (2.78×10 −3 K −1 ) were obtained at 420 °C because of a low porosity and fine grain size. It is proposed that a noble, new powder extrusion process, for the fabrication of high-performance Bi 2 Te 3 -based thermoelectric materials, be a useful technique.

Complete design specifications for 260 MeV H − beam extractors are presented. The extractor employs a novel design of a stripper magnet which separately handles both the stripping of the H− beam and the bending of the unextracted H− beam. The design objective of the extractor is to partially extract a negative hydrogen ion (H−) beam at 260 MeV from the main linac where both protons (H+) and negative hydrogen ions are accelerated up to 1 GeV . Since the extractor adopts the magnetic stripping method, emittance growth is unavoidable for the extracted beam. However, the unextracted H− beam returns to the main linac with no change in the beam profile. The main features of this extractor are: (1) its ability to regulate the intensity of the extracted beam and (2) the nondestructive effect on the profile of the H− downstream beam. These extractors will be utilized for the Korea Multi-purpose Accelerator Complex (KOMAC) linear accelerator of 1 GeV cw proton (H+)/negative hydrogen (H−) beams with an intensity of 20 mA .

The extensive design effort for KSTAR has been focused on two major aspects of the KSTAR project mission - steady-state-operation capability and advanced tokamak physics. The steady state aspect of the mission is reflected in the choice of superconducting magnets, provision of actively cooled in-vessel components, and long pulse current drive and heating systems. The advanced tokamak aspect of the mission is incorporated in the design features associated with flexible plasma shaping, double null divertor and passive stabilizers, internal control coils and a comprehensive set of diagnostics. Substantial progress in engineering has been made on superconducting magnets, the vacuum vessel, plasma facing components and power supplies. The new KSTAR experimental facility with cryogenic system and deionized water cooling and main power systems has been designed, and the construction work is under way for completion in 2004.

The Korea Superconducting Tokamak Advanced Research (KSTAR) project is the major effort of the national fusion programme of the Republic of Korea. Its aim is to develop a steady state capable advanced superconducting tokamak to establish a scientific and technological basis for an attractive fusion reactor. The major parameters of the tokamak are: major radius 1.8 m, minor radius 0.5 m, toroidal field 3.5 T and plasma current 2 MA, with a strongly shaped plasma cross-section and double null divertor. The initial pulse length provided by the poloidal magnet system is 20 s, but the pulse length can be increased to 300 s through non-inductive current drive. The plasma heating and current drive system consists of neutral beams, ion cyclotron waves, lower hybrid waves and electron cyclotron waves for flexible profile control in advanced tokamak operating modes. A comprehensive set of diagnostics is planned for plasma control, performance evaluation and physics understanding. The project has completed its conceptual design and moved to the engineering design and construction phase. The target date for the first plasma is 2002.

Requirements and design characteristics of the heating and current drive systems for KSTAR (Korean Super conducting Tokamak Advanced Research)1,2 tokamak are described. The neutral beam (NB), the i...

A new neutron reflectometer has been installed at the HANARO, research reactor in Korea. The scattering geometry is horizontal and, as a result, the sample is placed vertically. The wavelength of the incident neutron beam is 2.45 A, and monochromated by a pyrolytic graphite crystal with a mosaicity of 0.4°. A detection of the incident and reflected neutron beams is via a helium-3 neutron detector. The neutron reflectivities of deuterated polystyrene and SiO 2 thin films were measured using this instrument. A neutron reflectivity as low as 10 −6 was determined. The maximum neutron momentum transfer, Q , reached 0.4 A −1 for the solid thin films.

This work is concerned with the development and application of ion implantation techniques for improving the corrosion resistance of zircaloy-4. The corrosion resistance in nitrogen implanted zircaloy-4 under a 120 keV nitrogen ion beam at an ion dose of 3 × 1017 cm−2 depends on the implantation temperature. The characteristics of surface oxidation and corrosion resistance were analyzed with the change of implantation temperature. It is shown that as implantation temperature rises from 100 to 724°C, the colour of specimen surface changes from its original colour to light yellow at 100°C, golden at 175°C, pink at 300°C, blue at 440°C and dark blue at 550°C. As the implantation temperature goes above 640°C, the colour of surface changes to light black, and the surface becomes a little rough. The corrosion resistance of ziracaloy-4 implanted with nitrogen is sensitive to the implantation temperature. The pitting potential of specimens increases from 176 to 900 mV (SCE) as the implantation temperature increases from 100 to 300°C, and decreases from 900 to 90 mV(SCE) as the implantation temperature increases from 300 to 640°C. The microstructure, the distribution of oxygen, nitrogen and carbon elements, the oxide grain size and the feature of the precipitation in the implanted surface were investigated by optical microscope, TEM, EDS, XRD and AES. The experimental results reveal that the ZrO2 is distributed mainly on the outer surface. The ZrN is distributed under the ZrO2 layer. The characteristics of the distribution of ZrO2 and ZrN in the nitrogen-implanted zircaloy-4 is influenced by the implantation temperature of the sample, and in turn the corrosion resistance is influenced.

The purpose of this investigation is to develop the relationship between implantation conditions and material properties for nitrogen implanted Zircaloy-4. The distribution of precipitation in annealed Zircaloy-4 is homogeneous. The size of most precipitate particles is in the range 10–200 nm and the dislocation density is very low. Microanalysis of the precipitation of the substrate shows that these particles are Zr(Fe,Cr) 2 ternary intermetallics, which have both hexagonal Laves-phase Zr(Fe,Cr) 2 structure and cubic Zr(Fe,Cr) 2 structure with a higher Fe:Cr ratio (from 1.53 to 2.47). The average value of microhardness of the substrate was measured to be Hv 221. After implanting nitrogen in Zircaloy-4, the dislocation density was significantly increased and a dislocation substructure was formed in the implanted layer. The original precipitate did not change obviously. The ZrN phase was discovered in the implanted layer. The dislocation substructure and the amount of ZrN were varied with increasing implantation temperature and dose. As the implantation temperature varied from 310 °C to 640 °C, the average value of microhardness was increased to Hv 580 and Hv 740 respectively. The effect of implantation temperature and dose on the microstructure, phase structure and composition, and surface hardness is presented in this paper.

The objective of this study was to identify genetic variants in the bovine fatty acid synthase (FASN) gene and to evaluate associations with fatty acid composition from longissimus lumborum muscle using 90 purebred Hanwoo steers. Sequence alignments observed 6 genetic variants located in exons 20, 24, 32, 34, and 39, and PCR–RFLP analysis confirmed these variations. Genotypes of the g.15532A>C locus were significantly associated with Linolenic acid (C18:3), and genotypes of the g.17924G>A locus were significantly associated with Palmitic (C16:0), Palmitoleic (C16:1), Oleic (C18:1), saturated fatty acids, and unsaturated fatty acids. The analysis revealed that SFA and UFA showed significant correlations with fatty acid composition (Myristic (C14:0), Palmitic (C16:0), Stearic (C18:0), Oleic (C18:1), and Eicosenoic (C20:1) acids). Oleic acid (C18:1) was negatively correlated with Myristic (C14:0), Palmitic (C16:0), and Palmitoleic (C16:1) acids (P

By investigating the differential reflection coefficient for one-phonon transition, various properties of the scattering of the He-Ag(111) system are studied. The formulation employed here is based on the distorted-wave Born approximation of an ab initio time-independent scattering theory. In the formulation, an arbitrary pair potential between the projectile and the crystal atoms together with the dispersion relation and the polarization vectors can be input. A model of a 69-layer slab is chosen for the computation of the vibrational modes. The plate modes are then mapped onto the Rayleigh modes. Using a pair potential proposed by others we calculated the differential reflection coefficient for one-phonon transitions corresponding to the Rayleigh modes. The phonon wave vectors are chosen along the (112) direction with magnitude ranging from 0.10 to 0.90 A −1 . The shape of the differential reflection coefficient is in agreement with experiment by other workers if we choose the amplitude of the Rayleigh modes to be proportional to the square root of the phonon wave vectors. We find that the projectile mainly interacts with the vibrational motion of the atoms in the first layer of the crystal, and the interaction reaches the third layer for small parallel momentum transfer and no deeper than the surface for phonon wave vectors greater than 0.6 A −1 . We also find that the effect of the Debye-Waller factor is small as temperature increases from 60 to 300 K. The differential reflection coefficient increases with temperature due to the Bose-Einstein distribution of the phonons and is larger for phonon annihilation than for phonon emission as determined by the density of the final states of the projectile, the incident flux and the kinematic conditions of the scattering.

The creep of a metal matrix composite is discussed by emphasizing the role of an internal stress and its relaxation by diffusion. The internal stress is produced by a difference in strains of plastic character (eigenstrains) between the matrix and dispersoids of the composite. The matrix plastic strain which is caused by slip dislocation activity accumulates the internal stress. The eigenstrain of the dispersoids is brought about by diffusion which occurs to relax the stress. The balance between the accumulation and relaxation of the stress results in a stationary state of creep. When the matrix has a constant flow stress, the stationary creep rate is proportional to the applied stress over a threshold value which is the matrix flow stress multiplied by the volume fraction of the matrix. Transient creep deformation is also examined and, finally, the relation of the present analysis to the Nabarro-Herring and Coble creep is discussed.

A new type of coaxial higher-order mode (HOM) coupler with one hook and two stubs has been designed for PEFP SRF cavities to satisfy the HOM damping requirements of the superconducting RF (SRF) linac of the Proton Engineering Frontier Project (PEFP), and to overcome the notch frequency shift and feed-through tip melting issues. This paper presents details on the PEFP HOM coupler's structure, structure optimization, filter characteristics, electro-magnetic field distribution and a coupler installation tool.

An elliptical superconducting RF cavity of 700 MHz with betag=0.42 has been designed for the linac of the Proton Engineering Frontier Project (PEFP). A double-ring stiffening structure is used for a low-beta cavity for Lorentz force detuning. The results of the electron multipacting analysis of the cavity are presented. A HOM analysis shows that the HOM coupler's Qext is lower than 3times105, thus reducing the influence of dangerous modes on the beam instabilities and the HOM-induced power.

A new irradiation facility has been developed using not only electric magnets but also a rotatable stage. Generally, the scanning method using magnets has been widely used in most of facilities. However, in this study another new methods have been developed: Two scanning method using a rotatable stage have been proved to make uniform irradiation-as large as 20 cm in diameter with more than 90% uniformity. The mechanical wobbler system makes the same effect as the wobbler system. And the beam is swept along the spiral path with a fixed and variable angular frequency during the scanning in the spiral scanning system.

Building proton beam user facilities, especially deciding beam energy level, depends on the attached proton accelerator and users' needs. To adjust beam energy level, two methods are generally used. One is to directly adjust the beam in the accelerator. The other is to adjust beam energy after extracting from the accelerator. Degrader/Scatterer System has been installed in the MC-50 Cyclotron to adjust energy level of the beam used for various application fields. Its degrader and scatterer are made of Al foils and Au foils, respectively. Al thickness are 2, 1, 0.5, 0.3, 0.2, 0.1, 0.05, 0.03, 0.02, 0.01mm and Au thickness are 0.2, 0.1, 0.05, 0.03, 0.02, 0.01mm, respectively. In this study, suitable beam condition was adjusted through overlapping Al/Au foils of various thickness through simulation results. After that, LET(Linear Energy Transfer) value was indirectly acquired by measuring the bragg peak of the external beam through PMMA plastic Phantom and profile was measured by film dosimetry.

The development of a low-energy proton accelerator has started as the first phase of the Proton Engineering Frontier Project (PEFP). The low-energy proton accelerator system consists of a 50 keV proton injector, low-energy beam transport (LEBT), 350 MHz, 3 MeV radiofrequency quadrupole (RFQ), 350 MHz, 20 MeV drift-tube linac (DTL), and RF system. The proton injector is under operation, RFQ is testing RF power, and a design of DTL has finished.

The PEFP (Proton Engineering Frontier Project) was started at September 2002 whose main goals are to construct 100 MeV proton accelerator and develop beam utilization areas. In this project, 20 MeV DTL is scheduled to be constructed and tested within three fiscal years. The RF power delivery system for 20 MeV DTL was designed and its components were characterized at PEFP, KAERI. The RF power from a 350 MHz, 1 MW klystron is split into four legs to drive four tanks of the 20 MeV DTL. Each leg has a phase shifter to adjust the phase of the RF field in each tank. The design of the RF power delivery system of the 100 MeV accelerator will be based on experiences of the 20 MeV DTL RF system development.

The PEFP (Proton Engineering Frontier Project) was approved by the Korean government under its 21C Frontier R&D Program last year. Final goals of this project are construction of 100 MeV proton linear accelerator, development of beam utilization technologies, and promotion of related industrial technologies. Its major beam utilization areas are new genetic resource development, simulating space radiation environment, SOI(Silicon On Insulator) wafer development using ion-cut technology, and fast switching power semiconductor development. In addition, there are several small research projects concerned with basic science and nuclear physics. In the PEFP, 20 MeV proton beam will be supplied to the users for their experiments from the middle of 2007. This paper contains the conceptual design of user facilities and the construction results of 6 MeV proton beam test facility for pilot studies of the proton beam utilization experiments in the PEFP.

A 100-MeV high-intensity (20 mA CW) proton linac is being built in the KAERI (Korea Atomic Energy Research Institute), Korea. Beam diagnostic system for the machine require to include BCMs (Beam Current Monitors), BPPMs (Beam Position and Phase Monitors), and other devices. BCMs are of special importance for high-intensity proton linacs, since the control of beam loss is critical. They should have high stability and resolution better than 5E-4. BPPMs are for measuring beam position and phase (w.r.t RF) simultaneously, that are crucial for the successful commissioning and operation of the accelerator. All diagnostic devices are required to operate both in CW and pulsed (several ms) modes. Pulsed mode operation is useful when machine tuning and commissioning. In this article, we report the developmental status of beam diagnostic devices for the KOMAC accelerator, with detailed description on the BPPM PU design.

We have designed a conventional 20 MeV drift tube linac (DTL) for the Proton Engineering Frontier Project (PEFP) as a low energy section of 100 MeV accelerator. The machine consists of four tanks with 152 cells supplied with 900 kW RF from 350 MHz klystron. We have also studied beam dynamics in this structure and designed focusing quadrupole magnets. The details of the DTL design are reported.

A RFQ linac (3 MeV, 350 MHz, 20 mA, CW and 324 cm in length) is being built for the Korea Multipurpose Accelerator Complex (KOMAC). The physical and engineering design of the H/sup +//H/sup -/ RFQ linac are described. The fabrication process for the cold model and structure support is described. The current status of the RFQ is reported.

The design of electron induction accelerator for industrial applications, for example sterilization, is presented. The injector, the accelerating column, the Blumlein circuit pulse power supply and the beam extraction system of movable (compact and light) electron induction accelerator with 5 MeV electron energy and 100 kW electron beam power are described. >

In an attempt to get a high current metal ion beam of various solid elements including refractory metals, a gaseous duoPIGatron ion source was modified by placing a grid type cathode and a sputter target in the PIG chamber. Tungsten mesh was adopted as the cathode grid, and Ar gas was used for a support gas for sputter induction. For Cu, Fe, and Al, the ion current and ratio of the metal ion were obtained for various conditions of sputtering voltage, support gas pressure, arc current, magnet current, and beam extraction voltage. Results showed that the metal current density linearly changes with the sputtering voltage and magnet current. The ratio of the metal ions in the total current is larger at lower support gas pressure. Current densities for Al, Cu, and Fe were 4 mA/cm/sup 2/, 5.5 mA/cm/sup 2/, and 2 mA/cm/sup 2/, respectively, at an arc current of 3 A, an extraction voltage of 20 kV, and a sputtering voltage of 1 kV. The ratios of the metals in the extracted ion currents were 9%, 8%, and 5% for Al, Cu, and Fe, respectively. >

This paper describes a method of haptic display in the virtual world shared by multiple remote users connected via network. Up to now, most investigations of haptic display are devoted to those related to single user or if multiple users exist even share the resources including computers which has no difference from the case of single user. In this paper, we are interested in the display of force feel in collaborative virtual workspace where multiple users participate via communication network. Excluding the possibility of large time delay among the users, the way of configuring individual haptic display systems is presented including the computation of interaction forces, joint driving forces of haptic devices and simulation of the virtual objects. A haptic display system is developed consisting of two haptic display devices operated by two remote users, and experimental results showing the validity of the proposed method are also presented.

The KSTAR (Korea Superconducting Tokamak Advanced Research) project is the major effort of the Korean National Fusion Program to design, construct, and operate a steady-state-capable superconducting tokamak. The project is led by Korea Basic Science Institute and shared by national laboratories, universities, and industry along with international collaboration. It is in the conceptual design phase and aims for the first plasma by mid 2002. The key design features of KSTAR are: major radius 1.8 m, minor radius 0.5 m, toroidal field 3.5 T, plasma current 2 MA, and flexible plasma shaping (elongation 2.0; triangularity 0.8; double-null poloidal divertor). Both the toroidal and the poloidal field magnets are superconducting coils. The device is configured to be initially capable of 20 s pulse operation and then to be upgraded for operation up to 300 s with non-inductive current drive. The auxiliary heating and current drive system consists of neutral beam, ICRF, lower hybrid, and ECRF. Deuterium operation is planned with a full radiation shielding.

The KOMAC Test Facility (KTF) Radio-Frequency Quadrupole (RFQ) linac has been fabricated to accelerate a 20 mA proton beam from 50 keV to 3 MeV. Two types of a input RF coupler is designed to feed the RF power generated by klystron into the RFQ accelerating cavity.