Hyper Suprime-Cam: Camera dewar design Komiyama, Yutaka; Obuchi, Yoshiyuki; Nakaya, Hidehiko ...
Publications of the Astronomical Society of Japan,
01/2018, Letnik:
70, Številka:
SP1
Journal Article
Recenzirano
Abstract
This paper describes the detailed design of the CCD dewar and the camera system which is a part of the wide-field imager Hyper Suprime-Cam (HSC) on the 8.2 m Subaru Telescope. On the 1.°5 ...diameter focal plane (497 mm in physical size), 116 four-side buttable 2 k × 4 k fully depleted CCDs are tiled with 0.3 mm gaps between adjacent chips, which are cooled down to −100°C by two pulse tube coolers with a capability to exhaust 100 W heat at −100°C. The design of the dewar is basically a natural extension of Suprime-Cam, incorporating some improvements such as (1) a detailed CCD positioning strategy to avoid any collision between CCDs while maximizing the filling factor of the focal plane, (2) a spherical washers mechanism adopted for the interface points to avoid any deformation caused by the tilt of the interface surface to be transferred to the focal plane, (3) the employment of a truncated-cone-shaped window, made of synthetic silica, to save the back focal space, and (4) a passive heat transfer mechanism to exhaust efficiently the heat generated from the CCD readout electronics which are accommodated inside the dewar. Extensive simulations using a finite-element analysis (FEA) method are carried out to verify that the design of the dewar is sufficient to satisfy the assigned errors. We also perform verification tests using the actually assembled CCD dewar to supplement the FEA and demonstrate that the design is adequate to ensure an excellent image quality which is key to the HSC. The details of the camera system, including the control computer system, are described as well as the assembling process of the dewar and the process of installation on the telescope.
Vascular smooth muscle cell (VSMC) migration contributes to vascular remodeling after injury, whereas oxidative stress generated through dysfunctional redox homeostasis induces hypermigration, ...leading to arteriosclerosis. Platelet-derived growth factor (PDGF)-induced reactive oxygen species (ROS) serve as intracellular signaling molecules in VSMCs. Reactive sulfur species (RSS) may serve as a biological defense system because of the antioxidative properties of highly nucleophilic sulfane sulfur. However, insufficient information is available on its function in PDGF-induced VSMC migration. Here we show that PDGF significantly increased the levels of intracellular sulfane sulfur and that intracellular sulfane sulfur donors, donor 5a and Na
2
S
4
, inhibited the increase in ROS levels in PDGF-treated VSMCs and inhibited their migration. Consistent with the migration results, sulfane sulfur donors inhibited Akt phosphorylation, a downstream signaling molecule in the PDGF cascade, without affecting the autophosphorylation of PDGF receptor-β. Further, sulfane sulfur donors inhibited vinculin and paxillin recruitment to the leading edge of VSMCs in response to PDGF to decrease focal adhesion formation. These findings suggest that RSS are required for PDGF-stimulated VSMC migration through the regulation of the ROS-regulated Akt pathway, which may contribute to focal adhesion formation. Our findings provide insight into RSS as novel regulators of vascular redox homeostasis.
The effect of precooling treatments on phase behaviors of
N
-(2-hydroxy-4-methoxybenzylidene)-4′-
n
-butylaniline (OHMBBA) was investigated by differential scanning calorimetry (DSC) measurements. ...OHMBBA shows polymorphism with several metastable phases. We found that OHMBBA forms various solid phases depending on the cooling conditions, crystalline phases, glassy–liquid–crystal states, or a mixture of both. DSC-X-ray diffraction (XRD) clearly showed that OHMBBA crystallizes into new metastable phase (C
II
′) when cooled at 10 K min
−1
and stabilizes into the most stable phase (C
I
) during the heating process. We performed the simultaneous measurement of DSC-Raman spectroscopy for OHMBBA and successfully distinguished various crystalline phases and a glassy N phase thermally and/or spectroscopically. The exothermic heat by the irradiation for Raman spectroscopy was characteristics of the phases, which was observed by DSC in the simultaneous measurement. In addition, roughly continuous measurements of Raman spectroscopy detected the phase transitions of OHMBBA complementarily. This work demonstrates that DSC-Raman spectroscopy is very useful to detect the phase transitions and to identify the phases.
Graphical abstract
Temperature dependence of 1H NMR spin-lattice relaxation time is investigated of a 1:2 molecular complex of DABCO (1,4-diazabicyclo2.2.2octane) and iodopentafluorobenzene formed by the ...halogen-bonding between nitrogen and iodine atoms. Besides the known phase transition at 230 K from polar (space group Pc) to nonpolar (space group P21/c) phases, another first-order phase transition was suggested for the first time at 129 K. The correlation time of reorientational motion of DABCO molecule is determined as a function of temperature. The activation energies Ea of the motion were estimated to be 20 kJ mol−1 and 11 kJ mol−1 for the crystallographically nonequivalent DABCO molecules in the intermediate-temperature phase.
Display omitted
•1H NMR spin-lattice relaxation time T1 has been measured.•Correlation time of DABCO molecular motion was determined.•The correlation time reaches ca. 10−10 s at Tc around 230 K.•Another first-order transition was suggested for the first time at 129 K.
Guest water molecules confined in channels of porous coordination polymer crystals Ln2Cu3(IDA)6·nH2O (Ln = La, Nd, Sm, Gd, Ho, Er; IDA = NH(CH2COO)22−; n ≈ 9) exhibited large dielectric constants (ε) ...and antiferroelectric behaviors at high temperatures (e.g., ε(Sm) ≈ 1300 at 400 K). In addition, plots of the temperature dependence of ε showed broad peaks at ∼170 K, below which ε became very small. These puzzling temperature dependences of ε are consistent with the results of molecular dynamics simulations, suggesting the “freezing of thermal motion” of water molecules at ∼170 K.
Recently, organic polysulfides have been synthesized as cathode active materials exceeding the battery performance of sulfur. However, the conventional organic polysulfides have exhibited capacities ...lower than the theoretical capacity of sulfur because the π-organic moieties do not conjugate with the sulfur chains. In this work, the organopolysulfides, synthesized via inverse vulcanization using disulfide compounds, exhibited higher capacities equal to the theoretical capacity of sulfur because of enhanced electronic conductivity based on the conjugation between organic moieties and sulfur chains. Furthermore, the organopolysulfide including 1,3-dhitiol-2-thione moiety exhibited the highest capacity because of the enhanced electronic conductivity. This finding will pave the way to develop next-generation rechargeable batteries.
We have used differential scanning calorimetry (DSC) to investigate the phase transition of a liquid crystal, N-(4-methoxybenzylidene)-4-butylaniline (MBBA), confined within porous silica materials ...with one- and three-dimensional pore architectures. Each phase-transition temperature of the confined MBBA linearly decreased with the inverse pore size compared with that of bulk MBBA. However, the degree of temperature shift varied owing to differences in the pore architectures. In addition, when MBBA was confined within one-dimensional pores, the thermal anomaly associated with the phase transition from the nematic phase to the isotropic liquid phase was not observed in the DSC measurements.
Two pairs of C-24 epimeric (24
R
)-/(24
S
)-24-hydroxy-24-methyl-5
α
-cholestan-3
β
-yl acetates and (24
R
)-/(24
S
)-25-hydroxy-24-methyl-5
α
-cholestan-3
β
-yl acetates as well as some related ...24-ethyl oxysterol analogs were stereoselectively synthesized directly from the respective parent 24-alkyl sterols by a remote
O
-insertion reaction with 2,6-dichloropyridine
N
-oxide (DCP) in the presence of a catalytic amount of (5,10,15,20-tetramesitylporphrinate) ruthenium(II) carbonyl complex Ru(TMP)CO and HBr.
1
H- and
13
C-NMR signals serving to differentiate each of the two epimeric pairs were interpreted. The C-24 alkyl oxysterols epimeric at C-24 were found to be effectively characterized by the aromatic solvent-induced shift (ASIS) by C
5
D
5
N, particularly for the difference in the
13
C resonances in the substituted cholestane side chain. A method for differentiating the
1
H and
13
C signal assignment of the terminal 26-/27-CH
3
in the
iso
-octane side chain was also discussed on the basis of a combined use of the preferred conformational analysis and HMQC and HMBC techniques. The present method may be useful for determining the stereochemical configuration at C-24 of this type of 24-alkyl oxysterols.
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