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51.
Katsuo Mitani Toshimitsu Suzuki Akihiro Matsuo Yoshinobu Takegami 《Journal of polymer science. Part A, Polymer chemistry》1974,12(4):771-784
The 220-MHz proton magnetic resonance and infrared spectra of stereoregular polypropylenes polymerized with a number of Ziegler-Natta catalysts and isotactic polymers of low molecular weight obtained by thermal degradation of a highly isotactic polypropylene were measured in an attempt to obtain some information on the local regularity. The fraction of thermally degraded polymer soluble in diethyl ether shows stereorandomness (tactie sequence length is quite short), and the portion soluble in n-pentane has stereoblock character. The results so obtained provide strong evidence that racemic dyads of whole polymer consist of two models of racemic dyad isolated and racemic dyads in groups. The polymers prepared with vanadium catalyst systems show stereorandom character and these polymers have \documentclass{article}\pagestyle{empty}\begin{document}$\hbox{-\hskip-1pt-}\hskip-4pt({\rm CH}_2 \rlap{--} )$\end{document} groups formed by two propylene units in a tail-to-tail linkage. Syndiotactic polypropylene has head-to-head and tail-to-tail arrangements of two propylene units and this is the origin of randomness of syndiotacticity. 相似文献
52.
Kamata J Okada T Kotake Y Niijima J Nakamura K Uenaka T Yamaguchi A Tsukahara K Nagasu T Koyanagi N Kitoh K Yoshimatsu K Yoshino H Sugumi H 《Chemical & pharmaceutical bulletin》2004,52(9):1071-1081
As part of a series of studies to discover new topoisomerase II inhibitors, novel pyrimidoacridones, pyrimidophenoxadines, and pyrimidocarbazoles were synthesized, and in vitro and in vivo antitumor activities and DNA-protein and/or DNA-topoisomerase II cross-linking activity as an indicator of topoisomerase II-DNA cleavable complex formation were evaluated. The pyrimidocarbazoles possessed high in vitro and in vivo potencies. Compound 26 (ER-37326), 8-acetyl-2-[2-(dimethylamino)ethyl]-1H-pyrimido[5,6,1-jk]carbazole-1,3(2H)-dione, showed in vitro growth inhibitory activity with respective IC(50) values of 0.049 microM and 0.35 microM against mouse leukemia P388 and human oral cancer KB. In vivo, this compound inhibited the tumor growth of mouse sarcoma M5076 implanted into mice with T/C values of 42% and 13% at 3.13 and 6.25 mg/kg/d respectively without significantly affecting the body weight. In addition, compound 26 (ER-37326) increased the formation of DNA-topoisomerase II cross-linking in P388 cells. 相似文献
53.
Kimitoshi Fukudome Toshimitsu Suetsugu Takuya Ueshin Ryo Idegami Kazuki Takeya 《Applied Acoustics》2007,68(8):864-884
This paper proposes a method for the fast measurement of head related impulse responses (HRIRs) for all azimuthal directions using the continuous measurement method with a subject sitting on a servo-swiveled chair (SSC). The subject faces all azimuthal directions with a constant angular speed as the SSC rotates and hears corresponding spatial sounds. In our continuous measurement method, we use a maximum length sequence (MLS) as the excitation signal, record binaural signals using tiny microphones placed in the subject’s ear canal around 5 mm from the entrance, and feed them, along with the MLS signal, into a PC so that HRIRs can be extracted for all azimuthal directions and discrete elevations. In this paper, the underlying principles behind the method are described and conditions for successful implementation are examined through numerical simulations. Further, the validity of the proposed method is verified using a physical realization and empirical measurements. 相似文献
54.
The effects of methyl jasmonate (MeJA) on isoprenoid production were evaluated in cultured tissues of Scoparia dulcis. It was found that MeJA suppressed the accumulation of chlorophylls, carotenoids, phytol and beta-sitosterol in the tissues. MeJA, however, remarkably enhanced the production of scopadulcic acid B (SDB), with 10 microM being optimal observed concentration for stimulation of SDB production. The maximum concentration of SDB was observed 6 d after MeJA treatment. 相似文献
55.
Toshimitsu Yamazaki 《Hyperfine Interactions》2000,127(1-4):135-142
The metastable antiprotonic helium atom–molecule (in short, atomcule),
, which was discovered in 1991 as being the cause of the anomalous longevity of antiprotons with an overall lifetime of about
3 μs, now provides an exotic playground for laser spectroscopy, helped by the existence of numerous long lived states with
1–2 μs lifetimes. This three body system is characterized by a large angular momentum l ∼ 38 of
coupled with the electron in the 1s ground orbital, and looks like an exotic hydrogen isotope with many different “nuclear
states” as well as an exotic molecule with two centers (He2+ and
). So far, a number of laser resonance transitions have been identified. The present talk will cover the following topics:
(1) high precision spectroscopy in comparison with three body theories involving the relativistic effect and QED, and (2)
hyperfine structure of
;laser-microwave triple resonance.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
56.
Sakae Uemura Shin-ichi Fukuzawa Akio Toshimitsu Masaya Okano 《Tetrahedron letters》1982,23(11):1177-1180
Treatment of olefins with phenyltellurium(I) or (IV) species [(PhTe)2, PhTeCN, PhTeBr3] in alcohol at room to reflux temperature for 1–24 h produces the corresponding (2-alkoxyalkyl)phenyltellurium dihalides in good yields, the reaction being trans-stereoselective and highly regioselective. 相似文献
57.
An expression for the first-order probability density function of the laser speckle phase is analytically derived under the assumption that the speckle field obeys a non-circular, complex Gaussian, random process with a certain correlation between the real and imaginary parts of its complex amplitude. The probability density function of the speckle phase is actually evaluated for various cases and shown three-dimensionally as a function of the standard deviation of random object phase variations. The effect of random object phase variations on the probability density function is also investigated in detail. 相似文献
58.
Shinzi Kato Toshimitsu Kato Takashi Yamauchi Yutaka Shibahashi Etsuo Kakuda Masateru Mizuta Yoshio Ishii 《Journal of organometallic chemistry》1974,76(2):215-224
Some crystalline di- and tri-phenylstannyl esters [ArCS2SnPh3 and (ArCS2)2SnPh2] of aromatic dithio acids have been prepared in good yields and characterized. Preferential cleavage of the SnS bond of the ester was observed by treating them with primary and secondary amines as well as with phenacylidenetetramethylenesulfurane. 相似文献
59.
The relation between the velocity of a moving diffuse object and the mean number of integrated speckles in the certain time interval at the far-field plane of the object is obtained. By using this relation based on the first order statistics of integrated speckles, a new method of measuring the velocity of the diffuse object is proposed and experimentally verified. The first order probability density function of time-integrated speckles is also studied from which the validity of the present method is verified. 相似文献
60.
Junji Ohtsubo Toshimitsu Asakura 《Applied Physics A: Materials Science & Processing》1977,14(2):183-187
The probability density function and average contrast of the sum of two speckle patterns produced with various intensity ratios
and correlation conditions have been experimentally investigated. The experimental results are compared with the theoretical
ones obtained by Barakat and Goodman. Comparison shows excellent agreement between the experimental and theoretical results. 相似文献