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排序方式: 共有105条查询结果,搜索用时 15 毫秒
1.
Aging of concrete buildings and determining the pH value on the surface of concrete by using a handy semi-conductive pH meter. 总被引:1,自引:0,他引:1
A new method was devised for measuring the pH of a concrete surface by pHBOY-P2 with a piece of filter paper by extracting the pH value from concrete. This is a simple and inexpensive method that does not damage the concrete building, and is easy to apply on concrete samples for monitoring. By using the method mentioned above, a drastic decrease of the pH value of concrete bridges and buildings has investigated. The method is environmentally friendly to detect the pH value change of concrete as an environmental sample investigation. 相似文献
2.
Control of viscoelasticity using redox reaction 总被引:1,自引:0,他引:1
Tsuchiya K Orihara Y Kondo Y Yoshino N Ohkubo T Sakai H Abe M 《Journal of the American Chemical Society》2004,126(39):12282-12283
The viscoelasticity of a fluid was tuned with the Faradaic reaction of (11-ferrocenylundecyl)trimethylammonium bromide (FTMA), a "redox-switchable" surfactant. An aqueous solution of the reduced form of FTMA exhibited a remarkable viscoelasticity in the presence of sodium salicylate (NaSal) because of the formation of three-dimensional entanglement of wormlike micelles. Electrolytic oxidation of FTMA caused the viscosity of the system to dramatically decrease and the elasticity to disappear. This drastic decrease in viscoelasticity arose from the disruption of wormlike micelles. This novel electrorheological phenomenon is expected to be applicable to ink for inkjet printers, the electrochemically controlled release of substances entrapped in wormlike micelles of FTMA, and fluid flow rate control using electric signals. 相似文献
3.
Yoshio Kato Katsuo Komiya Yuuzi Sawada Hiroo Sasaki Tsutomu Hashimoto 《Journal of chromatography. A》1980,190(2)
The purification of enzymes was investigated by high-speed gel filtration on TSK-GEL G3000SWG columns packed with porous silica gel deactivated by chemically bonded hydrophilic compounds. Crude β-galactosidase from bacterial cells and commercial urease were purified ca. 15-fold in a single gel filtration. These enzymes were eluted within an hour from the column and the recoveries of enzymatic activity were almost 100% although the operation was carried out at room temperature (22°). Samples up to 100 mg could be applied to the column without loss of separation efficiency. 相似文献
4.
Takagi R Miyanaga W Tamura Y Ohkata K 《Chemical communications (Cambridge, England)》2002,(18):2096-2097
The Diels-Alder reaction of spirolactones with cyclopentadiene afforded the adduct with high pi-facial selectivity; a hydrophilic analogue of scyphostatin was synthesized from the Diels-Alder adduct. 相似文献
5.
Tetsuro Kato Ryosuke Nemoto Hisashi Mori Ryoetsu Abe Katsuo Unno Akio Goto Hideyuki Murota Masaoki Harada Motofumi Homma 《Applied biochemistry and biotechnology》1984,10(1-3):199-211
To achieve targeted distribution of anticancer drugs with sustained activity, ferromagnetic ethylcellulose microcapsules containing
an anticancer drug, mitomycin C (FM-MMC-mc), were prepared by a method based on phase separation principles. Two prototypes
of FM-MMC-mc were made: one with the drug as the core and zinc ferrite on its capsular surface (outer type); the other with
both the drug and zinc ferrite as the core (inner type). Both preparations provided a sustained-release property and a sensitive
response to conventional magnetic force, although certain differences in the release rate of drug, magnetic responsiveness,
and particle size were found between the two dosage forms. Animal studies showed that the magnetic microcapsules could be
magnetically controlled in the artery and urinary bladder. VX2 tumors in the rabbit hind limb and urinary bladder were successfully
treated with magnetic control of FM-MMC-mc. Pharmacokinetic study revealed that the targeting of the microcapsules markedly
enhanced the drug absorption into the surrounding tissues for a prolonged period of time. The results indicate the feasibility
and effectiveness of the magnetic microcapsules as a targeted drug delivery system. 相似文献
6.
Kusano G Orihara S Tsukamoto D Shibano M Coskun M Guvenc A Erdurak CS 《Chemical & pharmaceutical bulletin》2002,50(2):185-192
Investigation of the constituents of the fruits of Morus alba LINNE (Moraceae) afforded five new nortropane alkaloids (1-5) along with nor-psi-tropine (6) and six new amino acids, morusimic acids A-F (7-12). The structures of the new compounds were determined to be 2alpha,3beta-dihydroxynortropane (1), 2beta,3beta-dihydroxynortropane (2), 2alpha,3beta,6exo-trihydroxynortropane (3), 2alpha,3beta,4alpha-rihydroxynortropane (4), 3beta,6exo-dihydroxynortropane (5), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (7), (3R)-3-hydroxy-12-[(1S,4S)-4-[(1S)-1-hydroxyethyl]-pyrrolidin-1-yll-dodecanoic acid (8), (3R)-3-hydroxy-12-1(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid-3-O-beta-D-glucopyranoside (9), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-methyl-piperidin-1-yll-dodecanoic acid (10), (3R)-3-hydroxy-12-[(1R,4R,5S)-4-hydroxy-5-hydroxymethyl-piperidin-1-yl]-dodecanoic acid-3-O-beta-D-glucopyranoside (11), and (3R)-3-hydroxy-12-[(1R,4S,5S)-4-hydroxy-5-methyl-piperidin-1-yl]-dodecanoic acid (12) on the basis of spectral and chemical data. 相似文献
7.
An evaluation of the feasibility of liquid chromatography-mass spectrometry (LC-MS) with atmospheric pressure ionization was made for quantitation of four diarrhetic shellfish poisoning toxins, okadaic acid, dinophysistoxin-1, pectenotoxin-6 and yessotoxin in scallops. When LC-MS was applied to the analysis of scallop extracts, large signal suppressions were observed due to coeluting substances from the column. To compensate for these matrix signal suppressions, the standard addition method was applied. First, the sample was analyzed and then the sample involving the addition of calibration standards is analyzed. Although this method requires two LC-MS runs per analysis, effective correction of quantitative errors was found. 相似文献
8.
Yellow and colourless complexes of molybdophosphate were investigated by the use of laser Raman spectroscopy. Two kinds of yellow molybdophosphates were identified in the weakly acidic solutions: 12-molybdophosphoric and 11-molybdophosphoric acid which are in equilibrium in solution at pH 1-2. When excess phosphate is present, the colourless molybdophosphate is formed. This complex exists in the solutions of pH 4-1 under the condition of excess phosphate ([P]/[Mo] > 2). This complex was confirmed to be P2Mo5O6?23 and is so stable that the yellow molybdophosphate is converted into the colourless by excess phosphate. 相似文献
9.
As a remarkable orientationally ordered soft-condensed matter system, the smectic-C*(alpha) phase exhibits an incommensurate nanoscale helical pitch of more than four smectic layers. Recent theoretical advances predict the existence of a new phase showing a helical pitch of less than four smectic layers (<16 nm). By applying a novel optical technique to the study of freestanding films with increments in thickness of one smectic layer, we have measured the size of this pitch using 633 nm HeNe laser light. Our results confirm the existence of the newly predicted phase in one unique compound. 相似文献
10.
Huh D Tkaczyk AH Bahng JH Chang Y Wei HH Grotberg JB Kim CJ Kurabayashi K Takayama S 《Journal of the American Chemical Society》2003,125(48):14678-14679
This work is the first demonstration of electrical modulation of surface energy to reversibly switch dynamic high-speed gas-liquid two-phase microfluidic flow patterns. Manipulation of dynamic two-phase systems with continuous high-speed flows is complex and interesting due to the multiple types of forces that need to be considered. Here, distinct stable flow patterns are formed through a multipronged approach: both surface tension forces generated by surface chemistry modulation as well as viscous and inertial forces produced by fluid flows are employed. The novel fluidic actuation mechanism provides insights into better understanding microscale two-phase flow dynamics and offers new opportunities for the development of two-phase biochemical microsystems that are mechanically simple and operational at high speeds. 相似文献