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For many years, Wolter mirrors have been used as imaging elements in X-ray telescopes. The shape error of Wolter mirrors fabricated by replicating the shape of a mandrel originates from the replication error in electroforming. We have been developing an X-ray focusing mirror for synchrotron radiation X-rays, as well as a high-precision electroforming process. In this paper, we report on the application of the advanced electroforming process to the fabrication of Wolter mirrors for the FOXSI Sun observation project. We also discuss the figuring accuracy of the mandrel.

Electroforming replication is an essential technique for fabricating full-shell, grazing-incidence mirrors for use in space, laboratories, and synchrotron experiments. For X-ray astronomy, a nickel electroforming replication process was developed and is used to produce lightweight and high-resolution X-ray mirrors. In addition, the electroforming process for fabricating X-ray mirrors for use in synchrotron experiments has undergone remarkable development over the past decade. We expect that the use of the ground-based electroforming replication process for the production of optics for Xray astronomy will lead to further improvements in the performance of X-ray telescopes. This paper describes our ongoing development efforts in the nickel-electroforming replication process, including the results of a pilot study.

著者人数: 49名, Accepted: 2017-12-18, 資料番号: SA1170329000

ASTRO-H (Hitomi) is a Japanese X-ray astrophysics satellite just launched in February, 2016, from Tanegashima, Japan by a JAXA's H-IIA launch vehicle. It has two Soft X-ray Telescopes (SXTs), among other instruments, that were developed by the NASA Goddard Space Flight Center in collaboration with ISAS/JAXA and Nagoya University. One is for an X-ray micro-calorimeter instrument (Soft X-ray Spectrometer, SXS) and the other for an X-ray CCD camera (Soft X-ray Imager, SXI), both covering the X-ray energy band up to 15 keV. The two SXTs were fully characterized at the 30-m X-ray beam line at ISAS/JAXA. The combined SXT+SXS system effective area is about 250 and 300 cm(exp 2) at 1 and 6 keV, respectively, although observations were performed with the gate valve at the dewar entrance closed, which blocks most of low energy X-rays and some of high energy ones. The angular resolution for SXS is 1.2 arcmin (Half Power Diameter, HPD). The combined SXT+SXI system effective area is about 370 and 350 cm (exp 2) at 1 and 6 keV, respectively. The angular resolution for SXI is 1.3 arcmin (HPD). The both SXTs have a field of view of about 16 arcmin (FWHM of their vignetting functions).The SXT+SXS field of view is limited to 3 x 3 arcmin by the SXS array size. In-flight data available to the SXT team was limited at the time of this conference and a point-like source data is not available for the SXT+SXS. Although due to lack of attitude information we were unable to reconstruct a point spread function of SXT+SXI, according to RXJ1856.5-3754 data, the SXT seems to be working as expected in terms of imaging capability. As for the overall effective area response for both SXT+SXS and SXT+SXI, consistent spectral model fitting parameters with the previous measurements were obtained for Crab and G21.5-0.9 data. On the other hand, their 2-10 keV fluxes differ by about 20% at this point. Calibration work is still under progress. The SXT is the latest version of the aluminum foil X-ray mirror, which is extremely light-weight and very low cost, yet produces large effective area over a wide energy-band. Its area-mass ratio is the largest, 16 cm(exp 2)/kg, among ASTRO-H, Chandra, and XMM-Newton mirrors. The aluminum foil mirror is a still compelling technology depending on the mission science goal.

An intermediate-strength earthquake of magnitudeMj6.8 occurred on July 16, 2007, centered beneath the Japan Sea a few kilometers offshore of Niigata Prefecture in central Japan. We constructed a dense GPS network to investigate postseismic deformation after this event, choosing our GPS sites carefully so as to complement the nationwide GPS GEONET array. Coseismic displacements caused by the mainshock detected at some GEONET sites were used to estimate coseismic fault parameters. The results indicate that the geodetic data can be explained by a combination of two rectangular faults dipping northwest and southeast. Minor but definite postseismic deformation was detected largely in the southern part of the dense network. The time series of site coordinates can be characterized by a logarithmic decay function, and the estimated time constant seems to be almost similar in range to that of the 2004 Mid-Niigata Prefecture Earthquake. We also found a possible site instability at 960566 (Izumo-zaki, GEONET) caused by a small, local landslide associated with the mainshock and therefore concluded that the data obtained at this site should not be used for coseismic or postseismic analysis.

著者人数: 43名, Accepted: 2014-10-05, 資料番号: SA1140194000

In this paper, we propose a new multimodal interaction description language, MIML (Multimodal Interaction Markup Language), which defines dialogue patterns between human and various types of interactive agents. The feature of this language is three-layered description of agent-based interactive systems. The high-level description is a task definition that can easily construct typical agent-based interactive task control information. The middle-level description is an interaction description that defines agent's behavior and user's input at the granularity of dialogue segment. The low-level description is a platform dependent description that can override the pre-defined function in the interaction description. The connection between task-level and interaction-level is realized by generation of interaction description templates from the task level description. The connection between interaction-level and platform-level is realized by a binding mechanism of XML. As a result of the comparison with other languages, MIML has advantages in high-level interaction description, modality extensibility and compatibility with standardized technologies.

A nationwide GPS array with more than 1,000 permanent stations operated by the Geographical Survey Institute of Japan, has provided many invaluable deformation data such as co- and post-seismic, volcanic, and ongoing secular deformations in the Japanese islands. Based on daily coordinate data of the GEONET stations together with results from a regional network operated by Tohoku University, we derived a map of the strain rate distribution in NE Japan showing that there exists a notable strain concentration zone of EW contraction along the Volcanic Front. The area demonstrates active seismicity including some disastrous earthquakes. Recent seismic tomography studies have revealed the existence of inclined seismic low-velocity zones (LVZ) at depths shallower than ~150 km in the mantle wedge sub-parallel to the subducted slab. The inclined LVZ reaches the Moho right beneath the Volcanic Front, indicating that the formation of the strain concentration zone is closely related to the rheological structure of the island-arc system.

Many Global Positioning System (GPS) stations of the Geographical Survey Institute and Tohoku University in northeastern Japan observed clear coseismic and postseismic deformations associated with the M7.5 1994 Far Off Sanriku earthquake. Applying the geodetic inversion algorithm given by Yabuki and Matsu'ura (Geophys. J. Int., 1992, 109, 363–376) to the observed GPS data, we estimate in this paper the spatial distributions of the coseismic and postseismic slip on the boundary between the subducting Pacific plate and the overriding continental plate. It is noted that the coseismic slip estimated in this paper denotes the slip for a period between the day before and the day after the main shock. The inversion for coseismic slip shows that the main shock was thrust faulting typical for interplate earthquakes, which is consistent with the results of other seismological studies. The short-term postseismic deformation (STD) observed for a period of ca. 10 days between the main shock and its largest aftershock shows that the initially high deformation-rate was lowered rather rapidly in comparison with the subsequent long-term deformations (LTD) lasting longer than 1 year, which decreased at an almost constant low rate. The observed data of STD can be explained by postseismic slip distributed approximately on the same region as the faulting area of the main shock, where the moment release during this period is ca. 16% of that estimated for the coseismic slip. The region of the sliding causing LTD is found to have significantly expanded southward and downward (or westward) on the plate boundary. The moment released by the postseismic sliding for nearly 1 year amounts approximately to 80% of that released by the coseismic slip in addition to the contribution from uniform steady sliding due to the relative plate motion. Furthermore, we find from the inversion analysis a locked region to the south of the long-term postseismic sliding region on the plate boundary. The amount of nominal back-slip estimated is so large that the locked region of the plate boundary is considered to have been tightly coupled for the year of 1995. This study demonstrates that the GPS observation only for ca. 1 year can distinguish the decoupled region due to the postseismic sliding around the source area of the main shock from the coupled one of the plate boundary.

We report recent progresses on the fabrication of pre-collimators (PCs). The PCs are designed to mitigate stray lights for X-ray telescopes to be onboard ASTRO-H. Each PC consists of cylindrical aluminum shells (blades) wiht varying radii of 60-225 mm, alignment frames to guilde the blade positions, and the bade housing body. The alignment frame and the housing are made of Aluminum 6061 and 7075 alloy, respectively. Heat-forming process is introduced to the production to stabilize the blade shape in orbit. Precise curvature of radius (tolerance of 1mm) and the linearity along with the direction of incident X-rays (P.V. < 20 microns) ensure that the blades do not obscure the telescope aperature. Each PC blade is placed precisely on top of the respective reflector mirror shell to reduce off-axis X-ray photons that leads to a "ghost" image within the detector field of view. In September 2010, the PC design--its height, thickness, and material of blades--was fixed and we produced the engineering model (EM) for the Soft X-ray Telescopes (SXTs). Since then, vibration tests for the EM PC unit are carried out twice, verifying that the PC has sufficient structural strength to withstand severe conditions during its launch. The EM PC is also installed onto the SXT mirror housing fabricated at the NASA's GSFC to validate our PC assembly method without any loss of thetelescope's effective aperture area. Since August 2011, we have been manusfacturing the PC blades for the flight models. We hereby show the manufacturing processes and also results of stray-light measurement without PCs for the SXT EM (obtained at ISAS 30m beamline facility) and the HXT FM (obtained at SPring-8 synchrotron radiation facility).

数多くの既存橋梁の補修計画において, 限られた予算の範囲内でどの橋のどの部分を補修するかを的確に意思決定することは容易ではない. 本研究では, 補修対象となる既存橋梁群に対する補修橋梁と補修部位の組合わせ最適化問題にナップサック問題を適用し, 遺伝的アルゴリズムを援用することで最適解を得ようとする試みである. なお, 投資効果を最大にするために, 橋梁の健全度あるいは損傷度を橋梁点検台帳のデータに基づく数量化理論第II類の分析結果による判別関数により判定し, 補修効果を定量的に取り扱っている.

[1] A magnitude 7.3 foreshock occurred at the subducting Pacific plate interface on March 9, 2011, 51 h before the magnitude 9.0 Tohoku earthquake off the Pacific coast of Japan. We propose a coseismic and postseismic afterslip model of the magnitude 7.3 event based on a global positioning system network and ocean bottom pressure gauge sites. The estimated coseismic slip and afterslip areas show complementary spatial distributions; the afterslip distribution is located up-dip of the coseismic slip for the foreshock and northward of hypocenter of the Tohoku earthquake. The slip amount for the afterslip is roughly consistent with that determined by repeating earthquake analysis carried out in a previous study. The estimated moment release for the afterslip reached magnitude 6.8, even within a short time period of 51h. A volumetric strainmeter time series also suggests that this event advanced with a rapid decay time constant compared with other typical large earthquakes.

[1] Real-time crustal deformation monitoring is extremely important for achieving rapid understanding of actual earthquake scales, because the measured permanent displacement directly gives the true earthquake size (seismic moment, Mw) information, which in turn, provides tsunami forecasting. We have developed an algorithm to detect/estimate static ground displacements due to earthquake faulting from real-time kinematic GPS (RTK-GPS) time series. The new algorithm identifies permanent displacements by monitoring the difference of a short-term average (STA) to a long-term average (LTA) of the GPS time series. We assessed the noise property and precision of the RTK-GPS time series with various baseline length conditions and orbits and discerned that the real-time ephemerides based on the International GNSS Service (IGS) are sufficient for crustal deformation monitoring with long baselines up to ∼1,000 km. We applied the algorithm to data obtained in the 2011 off the Pacific coast of Tohoku earthquake (Mw 9.0) to test the possibility of coseismic displacement detections, and further, we inverted the obtained displacement fields for a fault model; the inversion estimated a fault model with Mw 8.7, which is close to the actual Mw of 9.0, within five minutes from the origin time. Once the fault model is estimated, tsunami waveforms can be immediately synthesized using pre-computed tsunami Green's functions. The calculated waveforms showed good agreement with the actual tsunami observations both in arrival times and wave heights, suggesting that the RTK-GPS data by our algorithm can provide reliable rapid tsunami forecasting that can complement existing tsunami forecasting systems based on seismic observations.

ASTRO-H is a general purpose X-ray observatory scheduled for launch in 2014. Two soft X-ray telescopes (SXT) and two hard X-ray telescopes (HXT) will be onboard covering energy range of 0.2 -80 keV. Thermal control of the telescope is similar to that of Suzaku, using a thermal shield (TS) placed in front of the telescope and a electric heater attached on the telescope housing. Thus it is required for a TS to have high soft X-ray transmission, low solar absorptance and a low infrared emissivity. To meet these requirement, TS should be made of thin plastic film coated by metal such as aluminum. Then most important property of TS is mechanical strength to survive various environments at the launch and in orbit. This paper describes designing of TS, method of TS production, various environmental conditions and tests, risk management of treatment of ultra-thin film of TS in the process of production, testing and assembling.

Currently numerous websites contain dynamic content, but it is difficult to create accessible websites with dynamic content compared to those with static content. Because many platforms can realize Rich Internet Applications (RIAs), it is important that this type of dynamic content become accessible. We propose a method to improve accessibility of RIAs. Our method consists of two phases. In the first phase, we develop libraries to realize accessibility of RIAs. In the second phase, the libraries are automatically applied to RIAs. As an example of platforms that realize RIAs, our research focuses on JavaFX Script.

[1] Using GPS observations, we have detected an aseismic slip event on the intraplate Dedana Fault that was triggered by the Iwate-Miyagi Nairiku earthquake (Mw6.8, 13 Jun 2008 UTC) on a nearby but separate fault. The observations cannot be satisfactorily explained in terms of either viscoelastic relaxation or poroelastic rebound, and we cannot explain the observed displacement time series without presuming that aseismic slip occurred on the Dedana Fault. This slip was likely triggered by the mainshock stress change. The detection of future such aseismic slip events on intraplate faults is likely to require denser geodetic networks than are currently in operation, but is important for fully characterizing the seismic hazard associated with intraplate earthquakes.

Context: Craniotabes in otherwise normal neonates has been regarded as physiological and left untreated. Objective: Our objective was to investigate the role of vitamin D deficiency in the development of craniotabes in normal neonates. Design and Setting: Newborn screening of craniotabes was conducted at the single largest obstetrical facility in Kyoto, Japan. Follow-up study at 1 month was conducted at Kyoto University Hospital. Subjects: A total of 1120 consecutive normal Japanese neonates born in May, 2006, through April, 2007, were included in the study. Main Outcome Measures: The incidence of craniotabes was scored each month. Neonates with craniotabes were followed up at 1 month with measurements of serum calcium, phosphorus, alkaline phosphatase (ALP), intact PTH, 25-OH vitamin D (25-OHD), urinary calcium, phosphorus, creatinine, and hand x-rays. Results: Craniotabes was present in 246 (22.0%) neonates, and the incidence had obvious seasonal variations, highest in April-May and lowest in November. At 1 month, infants with craniotabes had significantly higher serum ALP compared with normal neonates; 6.9% of them had elevated intact PTH over 60 pg/ml, and 37.3% had 25-OHD less than 10 ng/ml. When separately analyzed according to the method of feeding, 56.9% of breast-fed infants showed 25-OHD less than 10 ng/ml, whereas none of formula/mixed-fed infants did, and breast-fed infants had significantly higher serum PTH and ALP compared with formula/mixed-fed infants. Summary: These results suggest that craniotabes in normal neonates is associated with vitamin D deficiency in utero, and the deficiency persists at 1 month in many of them, especially when breast-fed.

[1] The northeastern Japan arc is located in a typical subduction zone and is a seismically active region where large interplate earthquakes have occurred repeatedly. The nationwide GPS network has made it possible to investigate the crustal deformation in unprecedented detail; however, vertical displacements are less accurate than the horizontal ones and have not been used to constrain interplate coupling models. In this study, GPS carrier phase data are analyzed in order to estimate three components of site displacements. The result indicates uplift along the Japan Sea coast and subsidence along the Pacific Ocean coast. Using the vertical site velocities together with the horizontal ones as the data for a geodetic inversion method, a new model of interplate coupling is constructed to explain both the horizontal and vertical velocities for the interseismic period from 1997 to 2001. The model demonstrates strong coupling in the area off Miyagi and in the area off Aomori through the area off Tokachi, including the areas of asperities. The downdip limit of the locked fault zone on the plate boundary has been estimated seismologically to be at a depth of 50–60 km in northeastern Japan, and the distribution of slip deficits derived in this study indicates that the transition zone extends down to a depth of about 100 km.

Crustal movement and seismic activity in the northeastern Japan arc are produced by a reaction of the Pacific Plate sinking under the continental plate. We have investigated the time variation of crustal strain obtained from analysis of extensometer installed at eleven crustal-movement observatories in the northeastern Japan arc. We then investigated, using the finite element method, the spatial distribution and time variation of the crustal strain and stress caused by plate subduction. We finally compared the results with microearthquake activity observed by the seismic network of Tohoku University. The spatial distribution and time variation of microearthquake seismic energy were elucidated in order to know the seismic circumstances around the eleven observatories. A contour map of the seismic energy distribution was obtained, showing a lineation of the seismic activity. The time variation of various strain components from 1967 to 1981 were revealed. With the accumulation of additional data, it is possible to recognize the propagation of the maximum shear strain in the direction S50°E at 40 km/year from the Pacific Ocean side to the Sea of Japan. A similar time variation of areal-dilatation was found at the five observatories located at a distance of more than 100 km. The directions of the compression axes derived from the composite focal mechanism solution of microearthquakes coincide well with those of principal strain obtained from data gathered using extensometers, indicating E–W compression in most of the observatories and N–S compression around MYK. The spatial distribution and the accumulation of crustal stress caused by plate subduction were investigated using the finite element method, and a comparison with a hypocenter distribution of microearthquakes was performed. The distribution of the crustal stress is closely related to the crustal structure, but the amplitude of the observed strain is affected by local structures around the stations.

A dense GPS network was established in 1997 around Ou Backbone Range (OBR), northeastern Japan, by deploying 28 continuous GPS stations to complement the sparse portion of GEONET operated by the Geographical Survey Institute of Japan. The aim of the network is to investigate the present surface deformation and understand the relationship between earthquake occurrence and the deformation process of the island-arc crust. Our GPS data are analyzed using a precise point positioning strategy of GIPSY/OASIS-II. Results of GEONET in daily SINEX files have been supplied by the GSI. Producing grid data of horizontal velocities and taking spatial derivatives, we derived a map of strain rate distribution. The results show that the region between 38.8° and 39.8°N in the OBR experiences notable concentration of east-west contraction. The region coincides with the area of active seismicity, including the focal areas of large earthquakes occurring in 1896 (M7.2), 1900 (M7.0), 1962 (M6.5), 1970 (M6.2), and 1998 (M6.1). Observed strain is larger than can be explained by the total moment release of earthquakes that occurred in the same period as this study. Possible sources of strain concentration may be viscoelastic deformation due to large earthquakes and/or aseismic slip along the deeper extension of the active faults.

Mt. Iwate (2,038 m) is an active volcano located in northeastern Japan. Unrest of the volcano started in September, 1995 with intermediate-depth tremors. The shallow seismicity gradually became active in February, 1998, accompanying the notable crustal deformation observed by a dense GPS network. The pattern of the horizontal displacements is characterized by radially directing outward from the volcano. We estimated the source position by inversion analyses for every two-months period, assuming two models; a point pressure source (Mogi model) and a tensile fault. The comparison of AIC’s for the two models indicates that the latter is proper from February to April, while the former is preferable afterward. The tensile fault was located at about 5 km WSW of the summit and 3 km in depth, then a Mogi source was estimated at the western neighbor of the tensile fault in the successive period and moved westward as far as 10 km W of the summit with shallowing its depth. It should be noted that the seismic area also expanded westward in the same period. This synchronicity suggests that the both phenomena were caused by a movement of magma from the deeper part beneath the summit to the western shallower part.

We have evaluated an anomalous crustal strain in the Tohoku region, northeastern Japan associated with a step-like stress change induced by the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0). Because the source area of the event was extremely large, the gradient of the observed eastward coseismic displacements that accompanied uniform stress change had a relatively uniform EW extension in northeastern Japan. Accordingly, the deformation anomaly, which is determined by subtracting the predicted displacement in a half-space elastic media from the observed displacement, should reflect the inhomogeneity of the rheology, or stiffness, of the crust. The difference of the EW extension anomaly between the forearc and backarc regions possibly indicates a dissimilarity of stiffness, depending on the crustal structure of the Tohoku region. The Ou-backbone range - a strain concentration zone in the interseismic period - shows an extension deficit compared with predictions. A low viscosity in the lower crust probably induced a relatively small extension. Meanwhile, the northern part of the Niigata-Kobe tectonic zone, another strain concentration zone, indicates an excess of extensional field. This is probably caused by a low elastic moduli of the thick sedimentation layer. The detection of strain anomalies in the coseismic period enables a new interpretation of the deformation process at strain concentration zones.

We propose a source fault model for the 2011, April 7, earthquake (M 7.1) deduced from a dense GPS network. The coseismic displacements obtained by GPS data analysis clearly show the spatial pattern specific to intraslab earthquakes, not only in the horizontal components but also the vertical ones. A rectangular fault with uniform slip was estimated by a non-linear inversion approach. The results indicate that the simple rectangular fault model can explain the overall features of the observations. The amount of moment released is equivalent to Mw 7.17. The hypocenter depth of the main shock estimated by the Japan Meteorological Agency is slightly deeper than the neutral plane between down-dip compression (DC) and down-dip extension (DE) stress zones of the double-planed seismic zone. This suggests that the depth of the neutral plane was deepened by the huge slip of the 2011, M 9.0, Tohoku Earthquake, and the rupture of the thrust M 7.1 earthquake was initiated at that depth, although more investigations are required to confirm this idea. The estimated fault plane has an angle of ∼60 degrees from the surface of the subducting Pacific plate. It is consistent with the hypothesis that intraslab earthquakes are thought to be a reactivation of the pre-existing hydrated weak zones produced in the bending process of oceanic plates around outer-rise regions.

Postseismic crustal deformation associated with the 2007 Chuetsu-oki Earthquake, which occurred on 16 July 2007 with a magnitude of 6.8 at the southeastern rim of the Sea of Japan, near the coast of Mid-Niigata Prefecture, Central Japan, are detected by GPS observations. We analyzed continuous GPS data from the sites of the Geographical Survey Institute of Japan (GSI) and another dense temporary network, which we established just after the main shock to reveal spatio-temporal evolution of postseismic slip for 50 days after the main shock by geodetic inversion methods. Four models of faults are configured following Ohta et al. (2008, this issue), and these are optimized based on ABIC (Akaike’s Bayesian Information Criterion). The results of the inversion analysis show that the postseismic slip on the faults occurred at a downdip and updip extension of the coseismically slipped portion. The slip in the shallower portion decayed to be negligible within 2 weeks, and the slip in the deeper portion was still large after the slip in the shallower portion had almost terminated.

A large earthquake ofMj7.2 occurred on June 14, 2008, beneath the border between Iwate and Miyagi prefectures in northeastern Japan. We propose a simple rectangular fault model based on a dense GPS network, including continuous GPS sites run by four agencies, to describe the coseismic deformation. The coseismic displacements are estimated by kinematic PPP (precise point positioning) analysis. Near the hypocenter, colocated independent instruments (integrated accelerogram and kinematic PPP) measure the same large displacement caused by the mainshock. The fault model explains the observations well and reproduces the observed complex spatial pattern, especially around the northern part of the focal area, which is the focus of a debate on whether or not the coseismic slip occurred on the Dedana fault system. Our results show that no major slip on the Dedana fault system occurred. The estimated amount of moment release was equivalent toMw6.9, and the maximum slip reached 3.5 m on the southern sub-fault.

A large earthquake with M7.2 occurred on August 16, 2005 along the plate boundary off Miyagi Prefecture. Co- and post-seismic deformations associated with this event were investigated to reveal the causal interplate slips using continuous GPS data and geodetic inversion. The coseismic slip distribution shows good agreement with that estimated by seismic waveform inversions. The major slip area is limited to the southeastern part of the rupture area of the previous 1978 event. The post-seismic slip extended to the southwest of the co-seismic slip area. These distinctive features of both the co- and post-seismic slips might be caused by the existence of the locked plate interface, where seismogenic stress has not released yet, in the northern part of the 1978 rupture area.

Web pages are used for a variety of purposes. End users must understand dynamically changing content and sequentially follow page links to find desired material, requiring significant time and effort. However, for visually impaired users using screen readers, it can be difficult to find links to web pages when link text and alternative text descriptions are inappropriate. Our method supports the discovery of content by analyzing 8 categories of link types, and allows visually impaired users to be aware of the content represented by links in advance. This facilitates end users access to necessary information on web pages. Our method of classifying web page links is therefore effective as a means of evaluating accessibility.