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1.
Tetsuo Irifune Chiaki Ueda Shohei Ohshita Hiroaki Ohfuji Takehiro Kunimoto Toru Shinmei 《高压研究》2020,40(1):96-106
ABSTRACTNano-polycrystalline diamond (NPD) with various grain sizes has been synthesized from glassy carbon at pressures 15–25?GPa and temperatures 1700–2300°C using multianvil apparatus. The minimum temperature for the synthesis of pure NPD, below which a small amount of compressed graphite was formed, significantly increased with pressure from ~1700°C at 15?GPa to ~1900°C at 25?GPa. The NPD having grain sizes less than ~50?nm was synthesized at temperatures below ~2000°C at 15?GPa and ~2300°C at 25?GPa, above which significant grain growth was observed. The grain size of NPD decreases with increasing pressure and decreasing temperature, and the pure NPD with grain sizes less than 10?nm is obtained in a limited temperature range around 1800–2000°C, depending on pressure. The pure NPD from glassy carbon is highly transparent and exhibits a granular nano-texture, whose grain size is tunable by selecting adequate pressure and temperature conditions. 相似文献
2.
The rate coefficient for the reaction of CCl3 radicals with ozone has been measured at 303 ± 2 K. The CCl3 radicals were generated by the pulsed laser photolysis of carbon tetrachloride at 193 nm. The time profile of CCl3 concentration was monitored with a photoionization mass spectrometer. Addition of the O3–O2 mixture to this system caused a decay of the CCl3 concentration because of the reactions of CCl3 + O3 → products (5) and CCl3 + O2 → products (4). The decay of signals from the CCl3 radical was measured in the presence and absence of ozone. In the absence of ozone, the O3–O2 mixture was passed through a heated quartz tube to convert the ozone to molecular oxygen. Since the rate coefficient for the reaction of CCl3 + O2 could be determined separately, the absolute rate coefficient for reaction ( 5 ) was obtained from the competition among these reactions. The rate coefficient determined for reaction ( 5 ) was (8.6 ± 0.5) × 10?13 cm3 molecule?1 s?1 and was also found to be independent of the total pressure (253–880 Pa of N2). This result shows that the reaction of CCl3 with O3 cannot compete with its reaction with O2 in the ozone layer. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 310–316, 2003 相似文献
3.
Endoscopic Observation of Tissue by Narrowband Illumination 总被引:6,自引:0,他引:6
Kazuhiro Gono Kenji Yamazaki Nobuyuki Doguchi Tetsuo Nonami Takashi Obi Masahiro Yamaguchi Nagaaki Ohyama Hirohisa Machida Yasushi Sano Shigeaki Yoshida Yasuo Hamamoto Takao Endo 《Optical Review》2003,10(4):211-215
We propose a new illumination method for a medical endoscope: narrow band imaging (NBI), in which the spectral bandwidth of the filtered light is narrowed. To confirm how the spectral specifications of the filtered light influence a reproduced image, an experiment was conducted observing the endoscopic images of the back mucosa of a human tongue. In addition, the effect of NBI on endoscopic images was investigated through preliminary clinical tests in colonoscopy and upper gastrointestinal endoscopy. It has been shown that NBI can enhance the capillary pattern and the crypt pattern on the mucosa. These patterns are useful features for diagnosing an early cancer. 相似文献
4.
The root heartwood of Dalbergia odorifera T. Chen (Leguminosae) is a Chinese medicinal drug (Japanese name koshinko) used for a stagnant blood syndrome (stagnation of disordered blood; Japanese, oketsu). In addition to 10 known compounds, five new phenolic compounds, isomucronustyrene and hydroxyobtustyrene (cinnamylphenols), (+)-isoduartin (isoflavan), odoriflavene (isoflav-3-ene) and (-)-odoricarpan (pterocarpan) were isolated and their structures were elucidated on the basis of chemical and spectroscopic methods. Of the fifteen compounds isolated, cinnamylphenols, isoflavans, isoflavene and benzoic acid derivative significantly inhibited prostaglandin biosynthesis as well as platelet aggregation induced by arachidonic acid. 相似文献
5.
35Cl NQR as well as heat capacity measurements of [(PyO)H][AuCl4] and its deuterated analog [(PyO)D][AuCl4] revealed successive phase transitions at 70.5 and 62.5 K, and at 71 and 63 K, respectively. The NQR frequency varied continuously through the upper transition point while discontinuously through the lower transition point. In the intermediate-temperature phase a remarkable decrease in the signal intensity was observed. These NQR observations as well as the feature of the heat capacity anomaly in which a broad peak is succeeded by a sharp peak with decreasing temperature suggest a possibility of normal-incommensurate-commensurate phase sequence. 相似文献
6.
In proportion to the environmental pollution problems caused by organotin compounds, the genotoxicities of tin compounds in the environments have become of interest so as to estimate their safety in recent years. In this work, isolated λ-DNA (double-strand DNA) was incubated with inorganic tin(II) and tin(IV) and five organotin compounds [n-butyltin trichloride, di(n-butyltin) dichloride, methyltin trichloride, dimethyltin dichloride and trimethyltin chloride] in reaction systems both with and without hydrogen peroxide (H2O2) content. The tin compounds tested in this study did not induce DNA breakage in the absence of hydrogen peroxide. Divalent inorganic tin (SnCl2) and tetravalent inorganic tin (SnCl4) caused DNA breakage in the presence of hydrogen peroxide (10 mM), and the DNA damage activity of inorganic tin was much more potent in divalent inorganic tin (SnCl2) than in tetravalent inorganic tin (SnCl4). Divalent inorganic tin (SnCl2) induced DNA breakage in a concentration-dependent fashion at concentrations greater than 0.1 mM of SnCl2 in the presence of hydrogen peroxide (10 mM). DNA breakage was not caused by n-butyltin compounds and methyltin compounds either in the presence or in the absence of hydrogen peroxide. 相似文献
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9.
Let m be an integer with m3. Let K and K be perfect fields of characteristic p and p such that (p,m)=1 and (p,m)=1, respectively. Moreover let A and A be algebraic function fields over K and K defined by xm+ym=a(0, ak) and xm+ym=a(a0 ak), respectively. Put g=(m–1)(m–2)/2. Denote by M(K,p,a) and M(K,p,a) the Hasse-Witt matrices of A and A with respect to the canonical bases of holomorphic differentials. Then we show that if p+p0(mod.m) then rank M(K,p,a)+rank M(K,p,a)=g and if pp1 (mod.m) then rank M(K,p,a)=rank M(K,p,a). 相似文献
10.
Tetsuji Kametani Hideo Lida Shinzo Kano Sadao Tanaka Keiichiro Fukumoto Shiroshi Shibuya Haruhiko Yagi 《Journal of heterocyclic chemistry》1967,4(1):85-92
Schotten-Baumann reaction of the amine (X) with 4-benzyloxy-3,4′-oxydiphenylacetyl chloride (XI) gave two amides, (XIIa) and (XIIb), which were cyclized to give the corresponding 3,4-dihydroisoquinolines, respectively. Methylation of the above 3,4-dihydro-isoquinolines, followed by hydrolysis, afforded the compounds having the same composition as berbamine (Ia) and oxyacanthine (Ib), whose structures are under examination. 相似文献