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101.
Refurbishment of a used in‐vacuum undulator from the National Synchrotron Light Source for the National Synchrotron Light Source‐II ring
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Toshiya Tanabe Harmanpreet Bassan Andrew Broadbent Peter Cappadoro John Escallier David Harder Charles Hetzel Dean Hidas Charles Kitegi Bernard Kosciuk Marco Musardo Johnny Kirkland 《Journal of synchrotron radiation》2017,24(5):919-924
The National Synchrotron Light Source (NSLS) ceased operation in September 2014 and was succeeded by NSLS‐II. There were four in‐vacuum undulators (IVUs) in operation at NSLS. The most recently constructed IVU for NSLS was the mini‐gap undulator (MGU‐X25, to be renamed IVU18 for NSLS‐II), which was constructed in 2006. This device was selected to be reused for the New York Structural Biology Consortium Microdiffraction beamline at NSLS‐II. At the time of construction, IVU18 was a state‐of‐the‐art undulator designed to be operated as a cryogenic permanent‐magnet undulator. Due to the more stringent field quality and impedance requirements of the NSLS‐II ring, the transition region was redesigned. The control system was also updated to NSLS‐II specifications. This paper reports the details of the IVU18 refurbishment activities including additional magnetic measurement and tuning. 相似文献
102.
9-(Diazomethylene)fluorene formed in the reaction of 9-(aminomethylidene)fluorene with n-butylnitrite, was successfully trapped by thiobenzophenone to afford 1,3,4-thiadiazoline derivative which was confirmed by spectroscopic and analytical data. 相似文献
103.
Hiromichi Arai Toshiya Kunisaki Yasuhiro Shimizu Tetsuro Seiyama 《Solid State Ionics》1986,20(4):241-248
The electrical conductivity of sintered specimens of (CeO2)1−x(CaO)x was investigated by employing a standard four-probe dc technique as a function of temperature between 400°C and 900°C, composition from 0.10x0.80, and oxygen partial pressure from 10−18 to 1 atm. The temperature and composition dependence of the emf have been carried out with a concentration cell. X-ray diffraction studies indicated that a cubic fluorite crystal remained in all specimens studied, although the solubility limit of CaO in CeO2 was assumed to lie close to 23 mol% from the change of the lattice constant. The magnitude of the conductivity decreased slightly with increase of the dopant concentrations up to x=0.50. The conductivity of these specimens was about 100 times larger than that of calcia-stabilized zirconia at 600°C with a smaller activation energies of 0.83–0.89 eV. With further increasing dopant concentrations, the magnitude of the conductivity was found to decrease remarkably. With an increase in the dopant concentration, the domain of primarily ionic conduction extended to a lower partial pressure. The conductivity of (CeO2)0.50(CaO)0.50 was found to be primarily ionic down to 10−12 atm even at 900°C. These results indicate that CaO-doped CeO2 may be more an attractive candidate for fuel cells and other applications. 相似文献
104.
Using gauge transformations on electron bond operators, we derive exact duality relations between various order parameters for correlated electron systems. Applying these transformations, we find two duality relations in the generalized two-leg Hubbard ladder at arbitrary filling. The relations show that unconventional density-wave orders such as staggered flux or circulating spin current are dual to conventional density-wave orders and there are direct mappings between dual phases. Several exact results on the phase diagram are also concluded. 相似文献
105.
This paper proposes a practical measurement system for bidirectional reflectance distribution functions (BRDFs) of a three-dimensional
(3D) object with a linear light source. Using the linear light source, the proposed system can reduce the number of image
acquisitions which are necessary for an estimation of the spatially-varying BRDFs of the object. Furthermore, the size of
the proposed system is much smaller than a conventional system which uses a parallel light. In this proposed system, the light
field of the linear light source is previously measured to determine direction and radiance of incident rays to each point
of the object, because the direction and radiance are not constant at each point. Using the proposed system, the BRDF of a
point of flat objects was experimentally measured, and results showed validation of the estimation accuracy of the proposed
system. Measurement efficiency of the proposed system was also evaluated by comparing reflectance model parameters estimated
by the conventional and proposed systems. For the estimation, the reflectance function of a 3D object was measured by both
systems. The estimation accuracy of the proposed method was also evaluated by comparing among a real image and rendered 3D
objects of the conventional and proposed methods. 相似文献
106.
Ca0.997Pr0.002TiO3 thin films that show strong red luminescence were successfully prepared by means of an excimer laser assisted metal organic deposition process with a KrF laser at a fluence of 100 mJ/cm2 at 100 °C. The CPTO films grew on the silica, borosilicate, and indium-tin-oxide coated glasses. The crystallinity of the Ca0.997Pr0.002TiO3 films depended on the substrates; the borosilicate and indium-tin-oxide coated glasses with a large optical absorption of a KrF laser (λ = 248 nm) were effective for the crystallization for the Ca0.997Pr0.002TiO3. In addition, a high thermal conductivity of the indium-tin-oxide coated glass substrate could also improve the crystallinity due to an enhancement of thermal propagation to the film. Oxygen annealing at 500 °C for 6 h successfully eliminated the oxygen vacancy produced by the laser irradiation, and also remarkably improved the PL emission intensity. Thus, we have shown that substrate properties such as an optical absorbance and a thermal conductivity were quite important factors for the crystal growth and the PL emission for the Ca0.997Pr0.002TiO3 in the excimer laser assisted metal organic deposition process. 相似文献
107.
Horino Y Kimura M Tanaka S Okajima T Tamaru Y 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(11):2419-2438
The terminal allene C(alpha)=C(beta) bonds of 4vinylidene-2-oxazolidinone (2) readily undergo [2+2] cycloaddition with a wide variety of terminal alkynes, alkenes, and 1,3-dienes irrespective of their electronic nature under strictly thermal activation conditions (70-100 degrees C) and provide 3substituted (Z)-methylenecyclobutenes 6, 3substituted methylenecyclobutanes 7 and 8, and 3vinylmethylenecyclobutanes 9, respectively, in good to excellent yields. Alkenes react with 2 with complete retention of configuration. The [2+2] cycloaddition is concluded to proceed via a concerted [(pi(2s)+pi(2s))(allene) + pi(2s)] Hückel transition state on the basis of experimental evidences and quantum mechanical methods. Some highly polarized enones and nitrile oxide, on the other hand, react with 2 selectively at the internal C(4)=C(alpha) double bonds and give spiro compounds 10 and 11, respectively. The bent allene bonds (173-176 degrees) and the unique reactivity associated with 2 are attributed to a low-lying LUMO (C(alpha)=C(beta)) that is substantiated by a through-space sigma*(N-SO(2))-pi*(C(alpha)=C(beta)) orbital interaction. 相似文献
108.
Ohkoshi S Arimoto Y Hozumi T Seino H Mizobe Y Hashimoto K 《Chemical communications (Cambridge, England)》2003,(22):2772-2773
Two-dimensional cyanide-bridged copper(II) octacyanotungstates(V), [(Cu(3-CNpy)2(H2O))2(Cu(3-CNpy)2(H2O)2)(W(CN)8)2] (3-CNpy = 3-cyanopyridine) (1) and [(Cu(4-CNpy)2)2(Cu(4-CNpy)2(H2O)2)(W(CN)8)2] x 6H2O (4-CNpy = 4-cyanopyridine) (2), were prepared and these compounds exhibited metamagnetic behavior with Néel temperatures of 8.0 K (1) and 4.4 K (2). 相似文献
109.
A family of permutations of [n] = {1,2,…,n} is (ε,k)‐min‐wise independent if for every nonempty subset X of at most k elements of [n], and for any x ∈ X, the probability that in a random element π of , π(x) is the minimum element of π(X), deviates from 1/∣X∣ by at most ε/∣X∣. This notion can be defined for the uniform case, when the elements of are picked according to a uniform distribution, or for the more general, biased case, in which the elements of are chosen according to a given distribution D. It is known that this notion is a useful tool for indexing replicated documents on the web. We show that even in the more general, biased case, for all admissible k and ε and all large n, the size of must satisfy as well as This improves the best known previous estimates even for the uniform case. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2007 相似文献
110.
Naoya Kishi Cheol‐Hee Ahn Jizhu Jin Toshiya Uozumi Tsuneji Sano Kazuo Soga 《Macromolecular rapid communications》2000,21(11):775-778
Supported type cocatalysts using triphenylcarbenium perchlorate (Ph3CClO4) were prepared by impregnation on inorganic carrier, magnesium chloride (MgCl2) and applied to ethylene polymerizations with rac‐Et[Ind]2ZrCl2. Homogeneous polymerizations with Ph3CClO4 were also carried out for comparison. The activity of homogeneous polymerization was much lower than that obtained with methylaluminoxane (MAO). On the other hand, rac‐Et[Ind]2ZrCl2 activated by the supported type Ph3CClO4/MgCl2 system displayed high activity comparable to that obtained with MAO. From the results of fractionation and polymerization of the rac‐Et[Ind]2ZrCl2‐Ph3CClO4/MgCl2 catalyst system, it was found that the increased activity mainly came from the active species in the supernatant part. UV‐vis spectroscopic measurements combined with ICP analysis indicate that the active species in the supernatant fraction are composed of a stoichiometric amount of perchlorate and metallocene catalyst. 相似文献