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101.
Kamonthip Sereenonchai Saowapak Teerasong Sumonmarn Chan-Eam Phoonthawee Saetear Nathawut Choengchan Kanchana Uraisin Natchanon Amornthammarong Shoji Motomizu 《Talanta》2010,81(3):1040-1252
This work presents a flow analysis method for direct quantitation of calcium carbonate in cement without pretreatment of the sample. The method is based on online vaporization of CO2 gas following acidification of the sample inside a small chamber that has a flow of acceptor solution passing around it. Solubilization of the CO2 gas into the acceptor stream changes the conductivity of the acceptor solution causing an increase of signal at the capacitively coupled contactless conductivity detection (C4D) placed at the outlet of the vaporization chamber. This chamber is an adaption from previous work reported on ‘membraneless vaporization’ (MBL-VP).The method can be used in the quality control of production of mixed cement. These cement materials usually have calcium carbonate contents at high concentration range (e.g., 33-99% (w/w) CaCO3). Analysis of samples by this method is direct and convenient as it requires no sample pretreatment. The method is low-cost with satisfactory accuracy and acceptable precision. 相似文献
102.
103.
Kunitaka Shoji 《Proceedings of the American Mathematical Society》2000,128(5):1313-1317
We prove that the decision problem of whether or not a finite semigroup has the representation extension property is decidable. 相似文献
104.
105.
Keiko Doi-Kawano Etsuko Nishimoto Yoshiaki Kouzuma Daisuke Takahashi Shoji Yamashita Makoto Kimura 《Journal of fluorescence》2009,19(4):631-639
The steady-state and time-resolved fluorescece spectroscopy is one of the most powerful method to detect and analyze subtle
conformation change and interaction between peptide elements in protein. Phytocystatin Scb isolated from sunflower seeds includes
a single Trp residue at position 85. In an attempt to investigate the interaction of the N-terminal region of Scb with the
first and second hairpin loops by fluorescence spectroscopy of Trp residue, two Scb mutants in which single Trp locates at
position 52 and 58, respectively, and their N-terminal removed mutants were generated. The N-terminal truncation changed the
fluorescence decay kinetics of Trp52 from the triple exponential to double. Furthermore, the time-resolved fluorescence anisotropy
residue indicated that the segmental motion of Trp52 was significantly enhanced by its N-terminal truncation. In contrast,
Trp58 and Trp85 had little influence. The N-terminal successive truncations of Scb and its mutants resulted in the weaken
inhibitors to papain. These results suggested that the N-terminal region of Scb interacts with the peptide segment preceding
the first hairpin loop, thereby stabilizing the conformation of the hairpin loop structure. 相似文献
106.
A simple flow injection analysis (FIA) method is described for the sequential determination of iron and copper. The detection method for iron and copper is based on their catalytic activities in the oxidation reaction of N,N-dimethyl-p-phenylenediamine (DPD) with hydrogen peroxide. The sequential determination of iron and copper can be carried out by injecting two sample plugs into the FIA system, sequentially. One injection does not contain triethylenetetramine (TETA), and is used for the sum of iron and copper concentration; the other which contains TETA is used only for the iron concentration. For iron determination, TETA is used as a masking agent of copper. The difference in peak height can be used for the calculation of copper concentration. Under the optimal conditions, the detection limits (3sigma) of 0.01 and 0.07 microg L(-1) were obtained for iron and copper, respectively. The proposed method can be applied to the determination of iron and copper in tap water and bottled-drinking mineral water samples. Good recoveries of the method, 98-103% for iron and 98-106% for copper, were achieved. 相似文献
107.
Yoshiko Murakami Kaoru Hiraiwa Yoshiaki Sasaki Isamu Fujiwara Shoji Tagashira 《Analytical sciences》2007,23(9):1147-1149
A micellar solution of cetylpyridinium chloride (CPC) can separate into two phases due to a temperature change or to the addition of salts. Platinum(II), (IV) and palladium(II) reacted with chloride ions to form stable anionic complexes of PtCl4(2-), PtCl6(2-) and PdCl4(2-), respectively, and were adsorbed onto the CPC gel phase. The CPC phase plays the role of an ion-exchange adsorbent for the anionic complexes. By such a procedure, the precious metals of platinum and palladium could be separated from base metals such as copper, zinc and iron. The kinetic separation was performed by a ligand exchange reaction of the palladium(II) chloro-complex with EDTA at 60 degrees C. The anionic palladium(II)-EDTA complex could not bind the opposite charged CP+ and was desorbed from the CPC phase. In the aqueous phase, the recovery of palladium(II) by the double-desorption was 101.1 +/- 1.2%. The platinum(II) and (IV) chloro-complexes were stable for at least 30 min and remained in the CPC phase. 相似文献
108.
109.
Takashi Ishida Mamoru Shoji Yoshiyuki Miyabata Yasumasa Shibata Eiji Ohno Shunji Ohaira 《Optical Review》1994,1(2):183-187
A high density mark edge recording method on a phase change rewritable disk is reported. A carrier-to-noise ratio of 55 dB for a mark length of 0.55,μm is obtained by using a 680 nm, NA 0.6 head and a phase change rewritable disk. In mark edge recording, it is necessary to record each mark in correct length. A new laser power modulation pattern is proposed. This pattern consists of a first-pulse, a multi-pulse chain and a last-pulse. Both positions of the first-ptilse and the last-pulse are movable. By adjusting these positions, a jitter, σ/Tw (Tw is window margin), is improved to 6.5% in high density EFM (Eight to Fourteen Modulation) recording of 0.4 μm/bit. 相似文献
110.
Using elastic recoil detection analysis and low energy electron diffraction we have investigated the adsorption process of hydrogen on the
surface. We find that (1) room temperature adsorption of atomic hydrogen induces a structure transformation from the
to Si(111)-1 × 1-Ag(H) structures, (2) a saturation coverage of hydrogen is 1.5 monolayer, which almost coincides with the one on a clean 7 × 7 surface, and (3) thermal desorption of hydrogen from the ordered 1 × 1-Ag(H) surface results in the recovery of the original
surface. 相似文献