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This paper describes solutions to calibrate the photon beam from the gradient bending magnet and to minimize the cross-talk between blades in the photon-beam position monitors in beamlines at Pohang Light Source II. The cross-talk was reduced by 99% applying the sensitivity normalization for each electrodes. The precise calibration was also achieved by considering additional kicks in the gradient bending magnet. The focusing force by quadrupole component in the bending magnet gives rise to an effect that simultaneously changes the vertical displacement of the source point and the emission angle. Experimental results agreed well with the transfer matrix calculations.

The present study investigates the effects of eudaimonia and hedonism on genre preferences by connecting eudaimonia and hedonism survey measures to individuals’ self-reported TV-show viewing data o...

Established media preference theories implicitly presume that audiences know a media product’s content or effects. Brands can fill this logical gap, with brands that media creators craft around the...

With novel schemes using reverse bends and longitudinal gradient bends, the 4th generation low-emittance storage ring was designed for the Pohange Light Source-III: the upgrade of PLSII. A unit cell with one homogeneous bending magnet, designed by using a genetic algorithm, is commonly used in the design of multi-bend achromatic lattices to realize an extremely low natural emittance (100 pm) for a 3-GeV and 280-m ring. In order to obtain enough dynamic aperture for accumulating off-axis injected beam from the existing PLS-II linear accelerator, we optimized the nonlinear dynamics with a genetic algorithm after a tune scan along the dynamic aperture. As a result, enough dynamic aperture for off-axis injection and long lifetime for stable top-up operation were achieved.

BACKGROUND AND PURPOSE The rate at which the chance of a good outcome of endovascular stroke therapy (EVT) decays with time when eligible patients are selected by baseline diffusion-weighted magnetic resonance imaging (DWI-MRI) and whether ischaemic core size affects this rate remain to be investigated. METHODS This study analyses a prospective multicentre registry of stroke patients treated with EVT based on pretreatment DWI-MRI that was categorized into three groups: small [Diffusion-Weighted Imaging Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS)] (8-10), moderate (5-7) and large (

The Korea fourth-generation storage ring (Korea-4GSR), with 4-GeV beam energy and 58-pm-rad emittance has been designed by the Pohang Accelerator Laboratory. The evaluated brilliance and coherence are approximately 100 times higher in the hard X-ray region in Korea-4GSR than in the third-generation storage ring at PLS-II. The coherence properties and preservation of coherence through beamline optical elements were studied using SPECTRA code and hybrid method. Result of this paper show essential information for planning experiments and designing beamlines using ultimate low emittance storage ring.

The macro versus micro debate in the brand personality literature has yielded a variety of micro approach brand personality scales for different media, with both differences and parallels in personality dimensions uncovered. The observed parallels in media brand personality dimensions and the varying media contexts under which empirical tests of selective exposure theories have been conducted suggest some common ground in the way that media product brands of different formats are perceived by individuals prior to selection and that the optimal method of measuring brand personality for media products may be neither broad macro inventories nor highly context-specific micro measures but somewhere in between. This article discusses the construction of a unified scale of media brand personality that can measure the personality of movie, TV show, pop song, news, and video game brands. The results of a two-step study consisting of free-association task (N = 1,440) and factor structure formation survey of...

Extraction mirrors installed at the most upstream position of interferometry beam size monitor are frequently used for measuring the beam size in storage rings. These mirrors receive the high power synchrotron radiation and are distorted owing to the heat distribution that depends on the position on the mirror surface. The distortion of the mirror changes the effective separation of the slit in the interferometry beam size monitor. Estimation of the effects of the front-end mirror distortion is important for measuring the beam size accurately. In this paper, we present the result of the numerical simulation of the temperature distribution and thermal expansion of the front-end mirror using ANSYS code, the theoretical basis of the effects of mirror distortion and compare with experimental results from Pohang Light Source II (PLS-II) at the Pohang Accelerator Laboratory (PAL). The equipment in the beam diagnosis line in PLS-II and experimental set-up for measuring the distortion of the front-end mirror using a multi-hole square array Hartmann screen are described.

Motor vehicle passenger airbags have been proven to be effective for reducing the possibility of passenger injury during a crash. However, the inflation of the airbag sometimes causes serious injury when a passenger is positioned close to the airbag. The United States Federal Motor Vehicle Safety Standard (FMVSS) 208 requires the use of a low-riskdeployment (LRD) passenger airbag system. This paper proposes a newly developed airbag system comprising two slim airbags mounted on the instrument panel. A series of tests were conducted using the FMVSS 208 test procedures to demonstrate the effectiveness of the proposed system. It was found that the system not only satisfied the injury criteria of FMVSS 208, but was also effective for protecting passengers of all sizes.

A very stable (≤10 ppm) magnet power supply (MPS) is required in an accelerator to achieve acceptable beam dynamics. Many factors affect the stability of an MPS, so design of the MPS requires much attention to noise-reduction schemes and to good processing of the signals from the feedback stage. This paper describes some design considerations for an MPS installed and operated in the Pohang Accelerator Laboratory: (1) control method, (2) oversampling technology, (3) ground isolation between hardware modules and (4) low-pass filter design to reduce the switching noise and rectifier ripple components, and shows the stability of three designed devices. The MPS design considerations were verified and validated in simulations and experiments. This paper also shows the relationship between stability and measurement aperture time of digital voltage meter 3458 A to measure stability of a current.

Synopsis We developed a carrier-envelope phase-stable, KTA parametric amplifier delivering 17-W mid-IR pulses (signal: 1.4 micron, idler: 3.8 micron) at a 100-kHz rep. rate. The key aspect is stable generation of supercontinuum seed pulses with 1.4-ps pulses, which are the longest for supercontinuum generation on its longer wavelength side. This technology offers a robust architecture with characteristics of stable phases, simple dispersion management, wavelength tunability for 1.3-4.5 micron, and this high photon flux opens novel statistics-driven spectroscopy for rare events in strong field physics.

The PLS-II, the upgraded PLS (Pohang Light Source), has been providing users with photon beams in the top-up mode since March 2013. The requirements for the PLS-II linac to achieve the top-up injection are very demanding because it is a full energy injector with a very limited energy margin. One of the requirements is to ensure high injection efficiency in order to minimize the beam loss at the storage ring injection point and the experimental hall during injection because loss leads to a high radiation level in the experimental hall. The energy stability and energy spread of the accelerated electron beam are fundamental parameters to monitor and manage for high injection efficiency. An energy feedback system consisting of a stripline-type beam position monitor and the last klystron was implemented. To diagnose the injected beam’s energy and energy spread in real time during top-up mode injection, we installed an optical transition radiation (OTR) monitor system upstream of the beam transport line (BTL) after the first bending magnet. The energy and the energy spread ranges can be controlled with a horizontal slit installed after the OTR monitor. The vertical beam size of the accelerated beam must be decreased for efficient injection because the electron beam is injected into the storage ring with many in-vacuum undulators of small gaps. For this purpose, two vertical slits were installed in the BTL region. We will describe mainly those instruments closely related to top-up operation, though other beam diagnostic instruments have been used since PLS.

The Pohang Accelerator Laboratory (PAL) is developing a self amplification of spontaneous emission (SASE) based free electron laser (FEL) for X-ray coherent photon sources. The PAL developed a prototype undulator that had a 5.0 m magnetic length and a 7.2 mm minimum gap at a magnetic field of ∼0.908 T. The PAL has constructed an undulator field measurement facility to confirm the field qualities of the X-ray free electron laser (XFEL) undulators in the assembly building. Two field measurement benches which included a Hall probe scanner, a flip coil and a stretched wire system were installed and their performances were evaluated. This paper describes the field measurement facility and presents the performance test results of the two benches.

This paper describes a start-to-end study of the suppression of stored-beam oscillation during top-up injection at the Pohang Light Source (PLS-II) beam line. The fast counterkicker implemented in PLS-II suppresses stored-beam oscillations in the vertical plane. During top-up injection in the magnetic spectroscopy beam line of PLS-II, flux improvement due to the suppression of stored-beam oscillation was clearly observed.

The incidence and clinical aspects of seizures remain to be elucidated in patients with acute pesticide intoxication. The present study included subjects who ingested pesticide with the intention of committing suicide and were treated at Soonchunhyang University Hospital (Cheonan, Korea) between January 2011 and December 2014. We analyzed the incidence and characterized the type and frequency of seizure, from the medical records of 464 patients with acute pesticide intoxication, according to the pesticide class. The effect of seizure on the clinical outcome was assessed. The incidence of seizure was 31.5% in patients who ingested glufosinate ammonium {2-amino-4-[hydroxyl (methyl) phosphinoyl] butyrate; ammonium DL-homoalanin-4-yl (methyl) phosphinate}, followed by those who ingested pyrethroid (5.9%) or glycine derivatives (5.4%). All of the seizures developed between 12 and 24 h of pesticide ingestion and had ceased by 72 h after seizure initiation, following treatment with antiseizure medication. Generalized tonic-clonic seizures were the most commonly observed (85.7% of the cases). Multivariable logistic regression analysis showed that the effect of seizure on mortality was not statistically significant. In conclusion, glufosinate ammonium herbicide is the most common seizurogenic pesticide class. Seizure itself was not a risk factor for mortality in patients with acute glufosinate ammonium intoxication.

The effects of an insertion device (ID) on the beam dynamics of the PLS-II storage ring have been investigated quantitatively. Although the linear perturbations caused by high field wigglers, such as tune shift and beta-beating, are corrected by using iterative Twiss-matching, particles may be unstable in the transverse planes due to nonlinear ID fields. Intrinsic non-linear fields and transverse magnetic field roll off cause ID field-perturbations making the beam unstable and possibly causing a reduction in the injection efficiency and the beam’s lifetime. Therefore, a frequency map analysis is used to analyze the transverse dynamics with high field IDs. In order to analyze the transverse dynamics by using frequency map analysis, we model a three dimensional magnetic field based on numerical data with a Taylor expansion to accurately represent the actual field. As a result, new operation tunes, 15.245 and 9.18, are suggested rather than the designed tunes of 15.28 and 9.18. The new tunes are used for Twiss-matching and require several iterations to reduce both the horizontal and the vertical beta beatings. In this paper, the effects of an insertion device and their compensations will be presented.

The Pohang Light Source II (PLS-II) has been operating successfully since the completion on March 21, 2012 of the PLS-II project to upgrade the PLS. Because top-up injection is becoming a general operation mode in the 3 rd generation light source, top-up operation using full energy injection from the 3 GeV linear accelerator is one of the main goals of the PLS-II. In the PLS-II topup operation, small beam loss of the injected beam in the storage ring and stored beam oscillation during injection are two main issues to be solved. The top-up mode has been successfully operated since March 19, 2013, because the beam loss of injected beam in the storage ring was reduced. As a result, the flux stability, excepting injection time, in the beam line has been dramatically improved. During injection, a systematic dip pattern occurs in the photon beam flux due to oscillation of the vertical stored beam. The main source of the oscillation of the vertical stored beam is the leakage field of Lambertson septum magnet. In this paper, the impact of lambertson septum magnet on the stored beam oscillation will be described and an improvement plan will be presented.

This paper describes the result of overall studies from development to characterization of undulator radiation. After three years of upgrading, PLS-II [1, 2] has been operating successfully since 21st March 2012. During the upgrade, we developed and installed an in-vacuum undulator (IVU) that generates brilliant X-ray beam. The IVU with 3 GeV electron beam generates undulator radiation up to ~ 21 keV using 11th higher harmonic. The characterizations of the undulator radiation at an X-ray beam line in PLS-II agreed well with the simulation. Based on this performance demonstration, the in-vacuum undulator is successfully operating at PLS-II., Comment: ICABU2015 conference (in Korea)

The non-linear effects caused by the intrinsic field transverse roll-off in an Elliptically Polarizing Undulator with 72-mm period and maximum peak field of 0.72 T (EPU72) on the dynamics aperture of the Pohang Light Source II (PLS-II) were investigated. A kick map and Frequency map analysis both demonstrated that EPU72 will not reduce the lifetime or cause injection problems in PLS-II., Comment: ICABU2015 conference

The compact size of the upgrade of Pohang Light Source (PLS-II) ring implies the use of gradient dipole magnets, with high field quality requirements. The PLS-II ring contains 24 such dipoles. Detailed 20 and 3D physical designs are reported; they include conformal mapping, equivalent 20 compact factor. residues fitting technique and end chamfer in a concise straight line style. According to the field measurement results, a beam based alignment technique for the rms variation reduction was employed. With that, the uniformities for these dipoles can be reduced to less than 2.0E - 04, and the rms variation from dipole to dipole can reach 5.82E-04. (C) 2012 Elsevier B.V. All rights reserved.

This paper presents a high-resolution voltage reference which is suitable for building high-precision magnet power supplies for accelerators. It consists of digital signal processor, field programmable gate array, and two digital-to-analog converter (DAC) boards. The DAC board uses two commercial 16-bit-D/A converters and an analog signal processing circuit to achieve a resolution higher than 20-bit. The proposed voltage reference has a resolution of 20-bit (1 ppm) for the +10 V full scale. The short- and long-term stabilities are ~1 and 5 ppm, respectively. The controllability and reproducibility of the output voltage to a step input were ~1 ppm (10 μV). The equivalent bandwidth of the voltage reference was ~5 kHz. These experimental results show that the proposed voltage reference may be applied to many other systems which require a high-resolution and cost-effective voltage reference with a good long-term stability. The voltage reference can be interfaced with the Ethernet (including EPICS), CAN, and RS232C.

Field Mapping System for the KIRAMS-30 Cyclotron Magnet K. H. Park, Y. D. Yoon, Y. G. Jung, D. E. Kim and B. K. Kang Pohang Accelerator Laboratory and Department of Electrical Engineering, Pohang University of Science and Technology, Pohang 790-784 J. Kang Cyclotron Application Laboratory, Korea Institute of Radiological and Medical Science, Seoul 139-706 J. S. Chai School of Information & Communication Engineering, Sungkyunkwan University, Suwon 440-764 (Received 12 August 2008, in nal form 5 December 2008) This paper presents a Hall-probe mapping system for measuring a cyclotron magnet. The system fabricated for the 30-MeV cyclotron at the Korea Institute of Radiological and Medical Sciences (KIRAMS). The Hall probes were mounted on a precision mechanical rotational stage and mapped the magnetic eld in a cylindrical coordinate system. The mapping system used the \ ying" mode eld mapping method to reduce the data-acquisition time. The time required for mapping the whole gap-area of the cyclotron magnet was 75 minutes. The relative random uctuation error during the entire mapping process was less than 0.01 %. The cyclotron magnet was corrected using the measured data for the magnetic eld. After the correction, the total phase excursion of the cyclotron was less than 12 , which is within the total phase excursion tolerance of 20 . PACS numbers: 41.20.-q

Accurate prediction of groundwater table is important for the efficient management of groundwater resources. Despite being the most widely used tools for depicting the hydrological regime, numerical models suffer from formidable constraints, such as extensive data demanding, high computational cost and inevitable parameter uncertainty. Artificial neural networks (ANNs), in contrast, can make predictions on the basis of more easily accessible variables, rather than requiring explicit characterization of the physical systems and prior knowledge of the physical parameters. This study applies ANN to predict the groundwater table in a swamp forest of Singapore. A standard multilayer perceptron (MLP) is selected, trained with the Levenberg–Marquardt (LM) algorithm. The inputs to the network are solely the surrounding reservoir levels and rainfall. The results reveal that ANN is able to produce accurate forecast with a leading time up to 7 days, whereas the performance slightly decreases when leading time increases.

Sintered Nd 2 Fe 14 B permanent magnets are damaged (demagnetized) by strong radiation, though some techniques of the magnets can reduce the sensitivity to radiation. High coercivity magnets show strong resistance to radiation, while they have a manufacturing dependence. Using magnets at very low temperature is effective. Stabilization under the appropriate annealing conditions enhances the radiation resistance successfully. Stabilizing by reverse field also increases the resistance. Combination of these techniques is much more effective, for example, annealed high coercivity magnets indicate very strong resistance.

Electrical discharge (ED) drilling is one of the prevalent processes that is utilised to drill deep holes in hard to machine materials such as nickel based heat resistant alloys used for turbine applications. In order to satisfy the high durability needs of heavy duty engines applicable to power generation industry, cooling design for hot gas path components has become complicated. ED drilling technique has been employed frequently to machine holes in complex parts. Thus, the effects of ED drilling and post electrical discharge machining (EDM) processes on the fatigue durability of the materials need to be clearly understood. However, the characteristics of the altered material zone (AMZ) created by ED drilling has not been fully analysed in terms of fatigue crack susceptibility. In order to investigate the effects of ED drilling process, fatigue test specimens with ED drilled through holes machined under four EDM conditions were fabricated. For some of the specimens, subsequent heat treatment was...

The objective of this study was to investigate the effects of electrical discharge machining (EDM) process conditions on the crack susceptibility of a nickel-based superalloy. Because sequential processes are inevitable in the manufacturing industry, the effects of EDM and post-EDM processes on the crack propagation behaviour of the components need to be clearly understood. The altered material zone (AMZ) of EDM processed Hastelloy X revealed different morphology before and after solution heat treatment. Depending on the EDM dielectric fluid and the post-EDM process such as solution heat treatment, it was found that cracks existing in the recast layer could propagate into substrate when a 20% strain tensile force was applied at room temperature. In the case of the kerosene electrical discharge (ED) machined specimens, it was observed that carburisation and sharp crack propagation along the grain boundary occurred after the heat treatment. However, the deionised water ED machined specimens after he...

This paper presents a Hall probe mapping system for measuring a cyclotron magnet, which has been fabricated for the 13 MeV cyclotron at the Korea Institute of Radiological and Medical Sciences. Two Hall probes are mounted on a precision mechanical x – y stage and map magnetic field in the Cartesian coordinate system. The mapping system uses the ‘flying’ mode field mapping method to reduce data-acquisition time. The time required for mapping the whole gap-area of the cyclotron magnet is ∼60 min. The relative measurement error for the averaged magnetic field along beam orbit is less than 0.02%. The cyclotron magnet has been corrected using field measurement data, and the achieved total phase excursion of the cyclotron after correction is less than ±15°, which is within the tolerance of ±20° for the total phase excursion.

The extrusion-cooking condition on Cordyceps pruinosa was designed using twin-screw extruder. Response surface methodology (RSM) was used to investigate extrusion-cooking using a central composition design with varying die temperature , feed moisture , feed rate (4-14 ka/h) and screw speed (120-280 rpm). System parameters (die pressure and specific mechanical energy (SME)) and extrudate parameters (density and water solubility index (WSI)) were statically analyzed using RSH. Die pressure was significantly affected by temperature, moisture contents and feed rate. SM was affected by screw speed and feed rate. When die temperature is and moisture content , the optimum pressure is shown. SME is about 20 Wh/kg, when feed rate is and screw speed . WSI was affected by temperature and moisture contents. Density was not affected by any factor. WSI increases by from about to about , as temperature is raised from . The WSI of Cordyceps pruinosa pulverized after extruding (PE) is about higher than that of raw material and higher than that of pulverized after drying (PD). The content of unsaturated fatty acid were not significantly different in PD and PE. Anti-oxidative activity of PE was 1.67-2.2 times higher than that of PD in Cordyceps pruinosa using 1- dipheny1-2-picrylhydrazyl method (DPPH).

Recent success in SASE-FEL experiments provides high confidence in achieving FEL radiation wavelengths as short as 0.1 nm.The SASE-XFEL requires multi-GeV electron beams with extremely low-emittance, short bunches, and long undulator systems. PAL is operating a 2.5-GeV electron linac as a full-energy injector to the PLS storage ring. With a proposed energy upgrade to 3.0 GeV and an in-vacuum undulator, PAL will be able to produce coherent X-ray radiation at wavelengths as short as 0.3 nm.This paper presents the preliminary design details for the proposed PAL-XFEL. The required undulator period is 12.5 mm with a 3-mm gap. The third harmonic enhancement technique can be used to obtain radiation wavelengths of 0.1 nm.The technical parameters related to these goals are reviewed.

Real-time metabolic monitoring of varied vascular beds provides the raw data necessary to conduct ultraprecise burn shock resuscitation based on second-by-second assessment of regional tissue perfusion. It also illustrates shortcomings of current clinical practices. Arterial base deficit was continuously monitored during 11 clinical resuscitations of patients suffering burn shock using a Paratrend monitor. Separately, in a 30% TBSA rat burn model (N = 70), three Paratrend monitors simultaneously recorded arterial blood gas and tissue pCO2 of the burn wound and colonic mucosa during resuscitation at 0, 2, 4, 6, and 8 ml/kg/%TBSA. Paratrend data were analyzed in conjunction with previously reported laser Doppler images of actual burn wound capillary perfusion. With current clinical therapy, continuous monitoring of arterial base deficit revealed repetitive cycles of resolution/worsening/resolution during burn shock resuscitation. In the rat model, tissue pCO2 in both burn wounds and splanchnic circulation differed depending on the rate of fluid resuscitation (P < .01 between sham and 0 ml/kg/%TBSA and between 2 ml/kg/%TBSA and 4 ml/kg/%TBSA). Burn wound pCO2 values correlated well with laser Doppler determination of actual capillary perfusion (ρ = −.48, P < .01). The following conclusions were reached: 1) Gratuitous and repetitive ischemia-reperfusion-ischemia cycles plague current clinical therapy as demonstrated by numerous “false starts” in the resolution of arterial base deficit; 2) in a rat model, real-time monitoring of burn wound and splanchnic pCO2 demonstrate a dose-response relationship with rate of fluid administration; and 3) burn wound and splanchnic pCO2 are highly correlated with direct measurement of burn wound capillary perfusion by laser Doppler imager. Either technique can serve as a resuscitation endpoint for real-time feedback-controlled ultraprecise resuscitation.

Pohang Accelerator Laboratory (PAL) is developing a Multipole Wiggler (MPW14) to utilize high-energy (B30 keV) synchrotron radiation at Pohang Light Source (PLS). The MPW14 is a hybrid type device to achieve maximum peak flux density and wide beam fan that can serve two beamlines. PLS MPW14-features period of 14 cm, minimum gap of 14 mm, 20 full field periods, maximum flux density of 2.06 T, 3036 mm total magnetic structure length. The peak flux density is very high compared to the other wigglers of similar pole gap and the period. The high peak flux density was possible using advanced new magnetic material and optimized magnetic geometry. The MPW14 will be used in hard X-ray region of 10–30 keV at 2.5 GeV electron energy. The total photon power is 6.19kW and the peak power density is 5.27 kW/mrad 2 at 2.5 GeV, 150 mA. To withstand the big magnetic loads with minimum deflections, C-type support structure is designed with detailed FEM structural analysis. In this article, all the conceptual design efforts for the PLS MPW14 wiggler will be described. r 2001 Elsevier Science B.V. All rights reserved. PACS: 41.85.L

Pohang Accelerator Laboratory is developing an Elliptically Polarized Undulator (EPU6) to utilize the polarized synchrotron radiation at Pohang Light Source (PLS). EPU6 is an Apple-II type elliptical undulator which changes the polarization of the field by translating the magnet arrays. EPU6 features period of 6 cm, minimum gap of 19 mm, 25 full field periods, maximum vertical flux density of 0.69 T, maximum horizontal flux density of 0.45 T, and 1575 mm total magnetic structure length. In this article, the design, fabrication, the measurement and correction efforts for PLS EPU6 undulator are described.

This paper presents a simple method to achieve 10−6 level of ripple fields in a large current DC magnet which is excited by a power supply of moderate ripple current content (10−4–10−5). A theory of the ripple field in a magnet with an auxiliary winding is derived and the conditions for ripple field reduction are obtained. When the resistance of the auxiliary circuit is much smaller than the reactance of that circuit, the ripple field bucking ratio is proportional to the quality factor of the auxiliary winding. To compare the theory with the experiment, a dipole magnet with an auxiliary winding was used. The auxiliary winding was either short-circuited or loaded with a resistor and the ripple fields were measured with a pickup coil placed in the magnet gap. When the auxiliary winding was short-circuited, a ripple field bucking ratio greater than 40 was achieved with a high output impedance power supply. This experimental result agrees well with the theory, and indicates that an auxiliary winding of a large cross-sectional area, instead of a large turn-number, is desired for an efficient ripple field reduction.

Laser-induced breakdown spectroscopy has been employed for the spectroscopic study of a laser-produced Zn alloy plasma for the analysis of Al impurities in Zn alloy. The laser-produced Zn alloy plasma was generated by a pulsed Nd:YAG laser (105 mJ, 3 ns). The physical characteristics of the laser-produced Zn alloy plasmas and an optimum condition for the composition analysis are reported. With the use of the relative intensities of spectral emission lines from standard samples, calibration curves for the analysis of aluminum in Zn samples were obtained in the case of air, vacuum, and Ar environments.

The effect of thermal stabilization (pre-baking at 142°C) on the sensitivity of neodymium–iron–boron (Nd 2 Fe 14 B) magnets to irradiation was studied. Thermally stabilized magnets showed higher resistance to irradiation with 2.0 GeV electrons: their demagnetization curves decrease linearly with respect to the number of electrons, and with a demagnetization rate remarkably smaller than that of the unbaked magnets.

Juxtacortical spots on fluid-attenuated inversion recovery (FLAIR) images can be frequently detected in patients with migraine. However, the origins of the cerebral lesions (including juxtacortical spots on FLAIR images) found in the previous studies are not known. We sought to investigate the association between juxtacortical spots on FLAIR images and right-to-left shunt (RLS) in migraine patients.Juxtacortical spots on FLAIR images were arbitrarily defined as small areas of hyperintensities in the juxtacortex and cortico-subcortical junction. The presence of RLS was examined by a transcranial Dopper (TCD) with the agitated saline test. The degree of RLS was categorized into four grades according to the number of microemboli: no shunt,10 microbubbles (MB),10 MB single spots pattern, and10 MB shower/curtain pattern. We compared the results for migraine patients (n = 49) with those for healthy controls (n = 49).Juxtacortical spots on FLAIR images occurred in 38/98 subjects; of them, 27/49 (55.1%) had migraines and 11/49 (22.2%) were healthy controls (P = 0.002). The independent factors associated with juxtacortical spots on FLAIR images were female, migraine patients, and RLS by multivariate analysis. In migraine patients, RLS was independently associated with juxtacortical spots on FLAIR images.Our results suggest that juxtacortical spots on FLAIR images were frequently found in migraine patients and might be associated with the presence of RLS in those patients. Further studies are needed to assess whether juxtacortical spots have clinical implications in patients with migraine.

Evidence of plastic deformation during contact sliding of silicon under relatively low loads at room temperature is presented. Sapphire spheres were slid against Si (1 0 0) under various normal loads at temperatures above and below the critical temperature. Upon chemical etching, pits that are attributed to dislocations developed along the sliding track for all experiments. This suggests that plastic deformation can readily take place in covalent solids, such as silicon, even at temperatures far below the critical temperature. The results of this work support the view that frictional force and energy dissipation are largely caused by plastic deformation of the materials near the sliding contact even under relatively low loads.

A chemical etching method is investigated as a possible approach to smoothing metal surfaces automatically. In a chemical etching process metal is removed due to chemical reaction and the dissolved species are transported away from the surface mainly by diffusion. Controlled dynamics introduced to the etchant motion provide the conditions necessary to perform preferential material removal such that an irregular surface is smoothed. A simplified model for the smoothing process based on fundamental mass transfer understandings is presented. Experimental results of smoothing electric discharge machined 440 stainless steel specimens are also presented. This work is motivated by the need to develop a cost effective way to manufacture molds during secondary processing.

Previous reports have indicated the association of periodontal diseases with elevated levels of serum immunoglobulin G (IgG) antibodies to periodontally relevant bacteria. Recent results from this laboratory suggest that enzymes proteolytic for immunoglobulins are important virulence factors of several periodontal bacteria. Specifically, enzymes from Porphyromonas (Bacteroides) gingivalis culture supernatant fluid (SF) cleaved human IgG (4 subclasses), IgA1 and IgA2, IgM, IgD and IgE. Proteolytic enzymes from Actinobacillus actinomycetemcomitans culture SF cleaved IgG, IgA and IgM. An enriched Ig proteolytic preparation from Capnocytophaga ochracea culture SF was shown to extensively cleave all 4 subclasses of human IgG. Extensive degradation of IgG and IgA in crevicular fluid samples on SDS-PAGE from periodontal disease sites of localized juvenile periodontitis (LJP) patients in comparison to little degradation in healthy sites indicated the potential role the proteolytic enzymes from periodontopathogenic bacteria may play in situ. Treatment of IgG with P. gingivalis, A. actinomycetemcomitans and C. ochracea SF resulted in similar patterns of degradation. LJP patients had significantly higher levels of IgG and IgA proteolytic activity in whole saliva than age-, sex-, and race-matched periodontal disease-free controls. However, not all of the proteolytic activity could be ascribed to bacterial proteases since neutrophils are also present in large numbers at diseased sites. Using similar techniques, lysates of neutrophils from healthy controls cleaved IgG, IgA and IgM. The observation of enhanced Ig cleavage activity in crevicular fluid and saliva in LJP patients suggest a role for Ig proteolytic enzymes in LJP.

Electron diffusion in tokamak geometry is calculated including both the Coulomb collisional pitch angle scattering and the electromagnetic drift wave fluctuation spectrum. In the weak fluctuation limit the neoclassical banana‐plateau diffusion coefficient is recovered. At higher fluctuation levels typical of the mixing length amplitude the anomalous transport formulas of drift wave turbulence are recovered using test particle simulations.

This project developed and demonstrated a new, bright, ultrafast x-ray source based upon laser-driven K-alpha generation, which can produce an x-ray flux 10 to 100 times greater than current microfocus x-ray tubes. The short-pulse (sub-picosecond) duration of this x-ray source also makes it ideal for observing time-resolved dynamics of atomic motion in solids and thin films.

In recent years, efforts to develop micro-robots for medical applications have been expanding. One of the key design issues in such micro-robots is to attain adequate frictional interaction between the robotic foot and the organ tissue. Particularly, it is important to generate the necessary frictional force without damaging the tissue. In this work, a design for the robotic foot was developed based on the frictional behavior of a tube structure. Fundamental experiments were initially performed to understand the bio-tribological behavior of a single tube. Then the design was modified to a multi-foot structure to achieve adequate friction. Bio-tribological investigation of a multi-tube foot in contact with a small intestine specimen of a pig was conducted. Friction tests were conducted using a pin-on-reciprocator type bio-tribotester. It was found that the multi-tube foot shows stick-slip behavior when slid against the small intestine specimen. The major mechanism behind the stick-slip behavior was due to interlocking between the tubes and the surface structures of the intestine specimen. Results of this work may be utilized for optimum design of frictional surface of medical micro-robots and other biological devices.Copyright © 2007 by ASME

A three‐dimensional Hall probe mapping system for measuring the solenoid magnet of PLS photo‐cathode RF e‐gun has been developed. It can map the solenoid field either in Cartesian or in cylindrical coordinate system with a measurement reproducibility better than 5 × 10−5 T. The system has three axis motors: one for the azimuthal direction and the other two for the x and z direction. This architecture makes the measuring system simple in fabrication. The magnetic center was calculated using the measured axial component of magnetic field Bz in Cartesian coordinate system because the accuracy of magnetic axis measurement could be improved significantly by using Bz, instead of the radial component of magnetic field Br. This paper describes the measurement system and summarizes the measurement results for the solenoid magnetic of PLS photo‐cathode RF e‐gun.

Pohang Accelerator Laboratory(PAL) is planning a 0.3 nm SASE (Self Amplification of Spontaneous Emission) XFEL based on 3.7 GeV linear accelerator. For short saturation length, application of SPring8 type in vacuum undulator is needed. This reflects the experiences from SPring8 SCSS project. The end structures were designed to be asymmetric along the beam direction to ensure systematic zero 1st field integral. The thickness of the last magnets were adjusted to minimize the transition distance to the fully developed periodic field. This approach is more convenient to control than adjusting the strength of the end magnets. The final design features 4 mm minimum pole gap, 15 mm period, peak effective field of 1.09 Tesla. In this article, the physical design of the undulator, the design of the end structure, and the physics requirements of the undulator system will be presented.