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81.
Bradley DI Clubb DO Fisher SN Guénault AM Haley RP Matthews CJ Pickett GR Tsepelin V Zaki K 《Physical review letters》2006,96(3):035301
We describe measurements of the decay of pure superfluid turbulence in superfluid 3He-B, in the low temperature regime where the normal fluid density is negligible. We follow the decay of the turbulence generated by a vibrating grid as detected by vibrating wire resonators. Despite the absence of any classical normal fluid dissipation processes, the decay is consistent with turbulence having the classical Kolmogorov energy spectrum and is remarkably similar to that measured in superfluid 4He at relatively high temperatures. Further, our results strongly suggest that the decay is governed by the superfluid circulation quantum rather than kinematic viscosity. 相似文献
82.
K.B. Haley† 《International Journal of Mathematical Education in Science & Technology》2013,44(4):343-347
The paper reviews the history of education in operational research and indicates the needs both of a practitioner and of a manager. It describes how these can be met by standard course teaching and suggests some areas of development. 相似文献
83.
Experimental results on the nuclear spin-lattice and nuclear spin-spin relaxation times in the ferromagnetic EuB6 at temperatures below 4·2 K are presented using the external magnetic field,H
ext, in the range of 0 ⩽H
ext ⩽ 10 kG. Nuclear spin-spin relaxation time computed on the basis of the Suhl-Nakamura process turns out to be 3·2μs, which compares well with the experimental value 11·1μs obtained with the 10 kG magnetic field at 1·7 K. It is found that in the ferromagnetic EuB6,T
1 is approximately 5 × 103 times larger thanT
2 at 1·7 K with the 10 kG magnetic field. Thus the effect ofT
1 onT
2 can be neglected. From the experimental value ofT
2, the value of the homogeneous line broadening is found to be 14 kHz. The corresponding value obtained from the cw method
is 175 kHz. This evidently shows the presence of the inhomogeneous line broadening in the cw NMR. 相似文献
84.
Triazenes (RN=N-NR'R") are a class of compounds that hold much promise in preparative chemistry as they are reactive groups which are both stable and adaptable to numerous synthetic transformations. Useful to scientists in pharmacology, total synthesis, polymer technology, and the construction of novel ring systems, to name a few areas, triazenes also have a tendency to surprise chemists with new reactions and increasing applicability. This review highlights some of the recent advances and diversity possible with these types of systems. 相似文献
85.
Sloan Ayers Zhongmin Xu Matthew Haley Alice Yang Regina Black Susanne Kiau 《Tetrahedron letters》2018,59(27):2664-2667
Over-alkylation side products are common in the alkylation of amines by substitution. In the synthesis of the novel HIV Maturation inhibitor BMS-955176, two over-alkylation byproducts were routinely observed at the penultimate synthetic step, in which a thiomorpholine dioxide side chain was added to the core molecule by alkylation of a primary amine. These two byproducts had drastically different HPLC relative retention times, despite both containing only one additional side chain. Adding complexity to the challenge of solving their structures was the proclivity of the two byproducts to interconvert. Positive- and negative-ion HRMS, as well as isolation and 1D and 2D NMR were utilized to determine their structures. These byproducts were additionally problematic in that they led to daughter impurities at the API step. 相似文献
86.
Chris L. Vonnegut Blakely W. Tresca Prof. Darren W. Johnson Prof. Michael M. Haley 《化学:亚洲杂志》2015,10(3):522-535
The aryl–ethynyl linkage has been extensively employed in the construction of hosts for a variety of guests. Uses range from ion detection (e.g., of metal cations in the environment or industrial waste and of anions prevalent in nature), to molecular mimics for biological systems, and to applications targeting future safety issues (such as CO2 capture and indicators for the manufacture of chemical weapons). This Focus Review examines the utilization of the aryl–ethynyl linkage in engineering host molecules for a variety of different guests, and how the alkyne unit plays an integral part as both a rigid scaffolding section in host geometry design as well as a linker to allow conjugative communication between discrete π‐electron systems. 相似文献
87.
An Alkyne‐Appended,Click‐Ready PtII Complex with an Unusual Arrangement in the Solid State 下载免费PDF全文
Jonathan D. White Lindsay E. Guzman Dr. Lev N. Zakharov Prof. Michael M. Haley Prof. Victoria J. DeRose 《Angewandte Chemie (International ed. in English)》2015,54(3):1032-1035
To better understand the range of cellular interactions of PtII‐based chemotherapeutics, robust and efficient methods to track and analyze Pt targets are needed. A powerful approach is to functionalize PtII compounds with alkyne or azide moieties for post‐treatment conjugation through the azide–alkyne cycloaddition (click) reaction. Herein, we report an alkyne‐appended cis‐diamine PtII compound, cis‐[Pt(2‐(5‐hexynyl)amido‐1,3‐propanediamine)Cl2] ( 1 ), the X‐ray crystal structure of which exhibits a combination of unusual radially distributed CH/π(C?C) interactions, Pt? Pt bonding, and NH:O/NH:Cl hydrogen bonds. In solution, 1 exhibits no Pt? alkyne interactions and binds readily to DNA. Subsequent click reactivity with nonfluorescent dansyl azide results in a 70‐fold fluorescence increase. This result demonstrates the potential for this new class of alkyne‐modified Pt compound for the comprehensive detection and isolation of Pt‐bound biomolecules. 相似文献
88.
Wan WB Brand SC Pak JJ Haley MM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2000,6(11):2044-2052
Graphdiyne (1) is a member of a novel family of interesting and potentially important allotropes of carbon. Reported herein are the synthesis and spectroscopic characterization of model substructures 2-6. The macrocycles were prepared by the intramolecular cyclization of suitable alpha,omega-polyynes. Key to the success of this approach was the development of an in situ protiodesilylation/alkynylation reaction utilizing reactive phenylbutadiyne synthons. This new method has allowed for the preparation of the largest, most complete substructures of the graphdiyne network to date (3-6). 相似文献
89.
90.
Rachel Auzly-Velty Thierry Benvegnu Daniel Plusquellec Grahame Mackenzie Julie A. Haley John W. Goodby 《Angewandte Chemie (International ed. in English)》1998,37(18):2511-2515
Tubular supramolecular aggregates are formed from glycolipids 1 , which are closely related to natural components of membranes of archaebacteria. The glycolipids exhibit disordered columnar thermotropic and hexagonal lyotropic liquid crystal phases. Whereas formation of the mesophases is insensitive to stereochemical factors, formation of the tubules is dependent on the configuration of the stereocenters that are shown in the picture but not specified. 相似文献