We report on the variability of the iron K emission line in the Seyfert 1 galaxy MCG-6-30-15 during a four-day ASCA observation. The line consists of a narrow core at an energy of about 6.4 keV, and a broad red wing extending to below 5 keV, which are interpreted as line emission arising from the inner parts of an accretion disk. The narrow core correlates well with the continuum flux whereas the broad wing weakly anti-correlates. When the source is brightest, the line is dominated by the narrow core, whilst during a deep minimum, the narrow core is very weak and a huge red tail appears. However, at other times when the continuum shows rather rapid changes, the broad wing is more variable than the narrow core, and shows evidence for correlated changes contrary to its long time scale behaviour. The peculiar line profile during the deep minimum spectrum suggests that the line emitting region is very close to a central spinning (Kerr) black hole where enormous gravitational effects operate.
Anionic surfactants are used in greater volume than any other surfactants because of their highly potent detergency and low cost of manufacture. However, they have not been used as templates for synthesizing mesoporous silica. Here we show a templating route for preparing mesoporous silicas based on self-assembly of anionic surfactants and inorganic precursors. We use aminosilane or quaternized aminosilane as co-structure-directing agent (CSDA), which is different from previous pathways. The alkoxysilane site of CSDA is co-condensed with inorganic precursors; the ammonium site of CSDA, attached to silicon atoms incorporated into the wall, electrostatically interacts with the anionic surfactants to produce well-ordered anionic-surfactant-templated mesoporous silicas (AMS). These have new structures with periodic modulations as well as two-dimensional hexagonal and lamellar phases. The periodic modulations may be caused by the coexistence of micelles that differ in size or curvature, possibly owing to local chirality. These mesoporous silicas provide a new family of mesoporous materials as well as shedding light on the structural behaviour of anionic surfactants.
High-sensitivity wide-band X-ray spectroscopy is the key feature of the Suzaku X-ray observatory, launched on 2005 July 10. This paper summarizes the spacecraft, in-orbit performance, operations, and data processing that are related to observations. The scientific instruments, the high-throughput X-ray telescopes, X-ray CCD cameras, non-imaging hard X-ray detector are also described.
The effect of added decane, m-xylene, or squalane on the phase behavior of the polyoxyethylene dodecyl ether (C12EO n ) −water system was investigated as a function of polyoxyethylene (EO) chain length at 25 °C. When the surfactant is relatively lipophilic (more lipophilic than the balanced state), the type of liquid crystal is changed to the more lipophilic one upon addition of decane. The lamellar (Lα) to lipophilic reverse hexagonal (H2) transition takes place in the C12EO3 system. On the other hand, the hexagonal (H1) to hydrophilic discrete cubic (I1) liquid crystal transition occurs in the hydrophilic C12EO7 system. There are two kinds of effects of oil on the self-organizing structures. One is the “penetration effect”, in which oil molecules penetrate into the surfactant palisade layer and expand the effective cross-sectional area, a S. The other is “swelling effect”, in which oil molecules are solubilized in the core of aggregates and expand the volume of aggregates. In this case, the a S is almost constant. Due to the swelling effect, the H1−I1 phase transition takes place in the decane−C12EO7 system, whereas the Lα−H2 transition occurs in the decane−lipophilic C12EO3 system due to the penetration effect. This causes the opposite tendency of the change in the curvature of the surfactant layers in liquid crystals on each side of the balanced state. As a result, the phase behavior of surfactant is quickly changed from forming micelles to reverse micelles within a narrow range of the EO chain in the presence of oil. On the other hand, m-xylene tends to penetrate the surfactant palisade layer, and the H1−Lα transition occurs even in the hydrophilic C12EO7 system.
A phase diagram of a water−poly(oxyethylene) oleyl ether (POlE) system was constructed as a function of poly(oxyethylene) chain length at 25 °C. The POlEs contain a highly pure oleyl group, whose purity is above 99.7%. The POlEs are in a liquid state over a wide range of composition. The increase in the poly(oxyethylene) (EO) chain of POlE corresponds to the increase in the curvature of surfactant layer toward water or the increase in HLB (hydrophile−lipophile balance) number of the surfactant. Various self-organizing structures were found: hexagonal and lamellar lquid crystals, four kinds of isotropic liquid crystals, a sponge phase, and reverse hexagonal liquid crystal. The phase transition between normal hexagonal and lamellar liquid crystals were investigated at constant volume fraction of the oleyl group in system by means of small-angle X-ray scattering. Correlation among the phase behavior, the packing of oleyl chain in self-organizing structures, and the HLB of POlE is discussed. The effect of temperature on the phase behavior in the present system is also discussed.
We present the design parameters, production process, and in-flight performance of the X-ray telescope (XRT) onboard Suzaku. The imaging capability is significantly improved over the ASCA XRT, which had half-power diameters of ${3\rlap {.}{}^{\mathrm {\prime }}6}$, to ${1\rlap {.}{}^{\mathrm {\prime }}8}$–${2\rlap {.}{}^{\mathrm {\prime }}3}$ for all four XRT-I modules. The optical axes are found to be distributed within a radius of ${1\rlap {.}{}^{\mathrm {\prime }}3}$, which makes the observation efficiency of all the XRTs more than 97% at the XIS-default observing position. The vignetting over the XIS field of view predicted via ray-tracing coincides with that measured for observations of the Crab Nebula to within $\sim 10\%$. Contemporaneous fits of a power law to all of the XIS spectra of the Crab Nebula taken at the two standard observing positions (XIS/HXD-default positions) gives a flux consistent with that obtained by Toor and Seward (1974, AJ, 79, 995) to within $\sim 2\%$. The pre-collimator on the top of each XRT module successfully reduces the intensity of the stray light from the $20'$ and $50'$-off directions down to the level of pre-flight expectations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.