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991.
992.
993.
Abe K Abt I Ahn CJ Akagi T Allen NJ Ash WW Aston D Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Daoudi M 《Physical review D: Particles and fields》1995,52(9):4828-4838
994.
Scott Allen 《Journal of statistical physics》1995,79(1-2):165-181
A detailed analysis is reported examining the local magnetic susceptibility (r), in relation to the correlation functionG(R) and correlation length , of a spherical model ferromagnet confined to geometry =L
d –d
×
d
(
d
2,d>2) under a continuous set oftwisted boundary conditions. The twist parameter
in this problem may be interpreted as a measure of the geometry-dependent doping level of interfacial impurities (or antiferromagnetic seams) in theextended system at various temperatures. For
j
0, jd-d, no seams are present except at infinity, whereas if
j
= 1/2, impurity saturation occurs. For 0 <
j
< 1/2 the physical domain
phys =D
d –d
×
d
(D>L), defining the region between seams containing the origin, depends on temperature above a certain threshold (T>T
0). Below that temperature (T>T
0), seams are frozen at the same position (DL/2,d-d'=1), revealing a smoothly varying largescale structural phase transition. 相似文献
995.
Abe K Abt I Ahn CJ Akagi T Allen NJ Ash WW Aston D Baird KG Baltay C Band HR Barakat MB Baranko G Bardon O Barklow T Bazarko AO Ben-David R Benvenuti AC Bienz T Bilei GM Bisello D Blaylock G Bogart JR Bolton T Bower GR Brau JE Breidenbach M Bugg WM Burke D Burnett TH Burrows PN Busza W Calcaterra A Caldwell DO Calloway D Camanzi B Carpinelli M Cassell R Castaldi R Castro A Cavalli-Sforza M Church E Cohn HO Coller JA Cook V Cotton R Cowan RF Coyne DG D'Oliveira A Damerell CJ Daoudi M 《Physical review letters》1995,75(20):3609-3613
996.
Electrochemically prepared films of conducting polymers of polypyrrole and polythiophene and their blends with polyamide have been investigated by X-ray photoelectron spectroscopy. In the N1s region of the spectra of films containing polypyrrole the peak corresponding to N(+) at 402.0 eV is separated from that of neutral N. The intensity of the N(+) peak can be correlated with the electrical conductivity of the films and the spectroscopically derived ratio of F/N(+) is close to 4 indicating that one BF(-)(4) dopant ion is incorporated for every oxidized nitrogen center. In the spectra of films of polythiophene and its blends peaks corresponding to S and S(+) can not be resolved but again the F/C ratio correlates with the electrical conductivity. 相似文献
997.
998.
1-Phenylthymine and the carbocyclic analog of thymidine were obtained in yields of 84-87% by cyclizing the appropriate 3-methoxy-2-methylacryloylureas in dilute sulfuric acid. High yields of 1-phenylthymine also resulted when the cyclization was carried out in trifluoroacetic acid, in acetic acid containing toluenesulfonic acid (TSA), or by fusion of the urea with a catalytic amount of TSA. In comparison, the typical aqueous-alkali catalyzed cyclizations gave lower yields of the two thymines, and cleavage of the acryloylureas was shown to occur. However, cyclization in concentrated aqueous ammonia produced high yields of both thymine derivatives. 相似文献
999.
Supramolecular photonic therapeutic agents 总被引:1,自引:0,他引:1
McDonnell SO Hall MJ Allen LT Byrne A Gallagher WM O'Shea DF 《Journal of the American Chemical Society》2005,127(47):16360-16361
A new approach to achieving selectivity for photodynamic therapy based upon the reversible off/on switching of the key therapeutic property (singlet oxygen generation) of a supramolecular photonic therapeutic agent (SPTA) in response to an external stimulus in the surrounding microenvironment is described. A series of SPTA analogues with pH responsive receptors of varying pKa are presented, in which the generation of singlet oxygen is shown to be dependent upon a proton source. For example, systems have been constructed such that the excited state energy of the photosensitizer can be decayed by a rapid photoinduced electron transfer (PET) mechanism, resulting in virtually no singlet oxygen being generated, but when the amine receptor is protonated the PET mechanism does not operate and singlet oxygen is produced. In vitro efficacy demonstrated that the SPTA derivatives can be activated within cells and one analogue is measured to have an EC50 value of 5.8 nM when assayed in the MRC5 cell line. 相似文献
1000.
N. N. Laxmi Madhavi Gautam R. Desiraju Clair Bilton Judith A. K. Howard Frank H. Allen 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1359-1360
Molecules of the title compound, C16H14O, are chiral and crystallize in space group P with Z′ = 2, and with one R and one S molecule in the asymmetric unit. The conformations of the phenyl rings in the two independent molecules differ slightly. Supramolecular organization in the crystal is via tetrameric O—H?H(O) hydrogen‐bonded synthons formed separately by each conformer. These tetrameric synthons stack along the c axis via C[triple‐bond]C—H?O(H) hydrogen bonds. The only link between the conformer stacks is provided by weaker Cmethylene—H and Cphenyl—H interactions with πarene density. 相似文献