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11.
K. M. Kojima 《Applied magnetic resonance》1997,13(1-2):111-122
Muon spin relaxation (μSR) and nuclear magnetic resonance (NMR) are powerful probes of magnetism, which have been extensively applied to studies of spin gap systems. Comparison of results obtained with the two techniques gives complementary results, as each is sensitive to different aspects of spin gap magnetism. We discuss recent μSR measurements of the spin ladder compounds Sr n?1Cu n+1O2n , pure and doped Haldane materials (Y2?x Ca x )Ba(Ni1?y Mg y )O5, and doped spin Peierls compounds (Cu1?x Zn x )(Ge1?y Si y )O3. 相似文献
12.
13.
Using temperature-modulated
differential scanning calorimetry, the melting behaviour of poly(oxytetramethylene)-alt-(aromatic oligoamide) (POTM-alt-AOA)
has been studied in comparison with that of polyoxytetramethylene glycohols
(POTMGs). The apparent melting temperature of the block copolymers is found
to be less than that of the corresponding POTMGs by approximately 30°C.
The relaxation time of melting of a POTM segment has been estimated and compared
with that of POTMG. The relaxation time of POTM-alt-AOA
is slightly shorter than that of POTMG when the molar mass of the POTM segment
is 2900; however, it is longer when the molar mass is 1400. 相似文献
14.
Kojima T. Inoue E. Tsuchiya M. Ishimaru K. 《Journal of Thermal Analysis and Calorimetry》2003,72(2):737-742
TG, swelling, and viscometric studies are presented for the residues, PTHF/IPDI polymer networks, and the extracts, the linear
polymers and unreacted IPDI, after Soxhlet extraction of PTHF/IPDI reaction products. The products are obtained by reacting
PTHF with 650, 1400, (2×650+1×2900), or 2900 of molecular mass with IPDI at various concentrations in bulk. The results on
the swelling and the viscosity experiments suggest that the PTHF/IPDI reaction products have a usual expectable structure.
All the TG curves are a double stage curve. The initial stage and the last stage seem to reflect decomposition of PTHF chains
and vaporization of the remainder, IPDI, respectively. These are analyzed by a trial-and-error construction, supposing double
event behavior. The values of ratio of mass loss associated with the initial event, W01, to the mass loss associated with the last event, W02, are smaller than the expectable those. This suggests that Event 2 involves vaporization of the decomposition products of
PTHF moieties bonded to IPDI in addition to vaporization of IPDI.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
TG and DSC were carried out on PMAA-net-POTM in order to elucidate the relation between the heterogeneity and the thermal changes; moreover, TG and DSC were carried out on PPOTMDM and PMAA to compare the results. The onset temperature in the last stage in the TG curve of PMAA-net-POTM increases as the concentrations of DMF and POTMDM in the polymerization decrease. This is explained in terms of plasticizers effects. A single peak due to fusion of POTM chains appears in the DSC curves of most copolymers. However, it is not seen in the DSC curves of copolymers with high heterogeneity. This is explained in terms of the freezing of POTM chains by frozen heterogeneous moieties. 相似文献
16.
Structures and cytotoxic activity relationship of casearins, new clerodane diterpenes from Casearia sylvestris Sw 总被引:1,自引:0,他引:1
H Morita M Nakayama H Kojima K Takeya H Itokawa E P Schenkel M Motidome 《Chemical & pharmaceutical bulletin》1991,39(3):693-697
Casearins G-R, new cytotoxic clerodane diterpenes have been isolated from the leaves of Casearia sylvestris Sw. (Flacourtiaceae). Their structures have been elucidated by spectroscopic methods and chemical conversions, and their structure-activity relationships have been discussed. 相似文献
17.
Suzuki Masayasu Watamabe Nobuyuki Tamiya Eiichi Kataoka Tetsuro Tokunaga Tohru Karube Isao 《Applied biochemistry and biotechnology》1987,15(3):191-200
A novel tumor-detection system consisting of complementmediated cytolytic reaction and an image processing system was developed
for the simple and rapid determination of tumor cells.
The present system consists of a CCD image sensor, image memory board, personal computer, and microscope.
When monoclonal antibody 3C4, which is specific to the guinea pig hepatoma L-10, was added to cell suspension, only L-10 cytolysis
occurred. Cytolysis caused a decrease in brightness of the cells observed by phase-contrast microscopy. The phase contrast
image of the cells before cytolysis was converted to a digitalized signal and stored in computer memory. After cytolysis,
a brightness threshold above that of lysed cells was subtracted from the digitalized signal and compared to the signal stored
before reaction.
L-10 cells in mixed cell suspension were determined specifically by the system. Measurement time was only 2 sec and overall
time, including reaction time, was approximately 30 min. Since this method does not require a cell washing process, automation
of the whole system is possible. 相似文献
18.
Rearrangement of Tertiary Allyl Alcohols Induced by Bromination: The Effect of a Fluorine Substituent on the Rate and the Outcome of the Reaction The allyl alcohol bearing a methyl and a t-butyl group at the hydroxylated position was found to undergo a rearrangement when treated with bromine (or N-bromosuccinimide) in an aqueous medium and to afford a product mixture containing two regioisomeric ketones and one oxirane. Introduction of an additional methyl group or a fluorine atom at the non-terminal olefinic center led to a more selective discrimination between potential migratory groups. As the result of an exclusive t-butyl shift only one product, a ketone, was formed in both cases. Whereas the reaction rate was only slightly affected by the additional methyl group, it was substantially decreased by the fluorine atom. 相似文献
19.
20.