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排序方式: 共有211条查询结果,搜索用时 312 毫秒
1.
It is an important challenge to analyze a three-dimensional thermal flow field in engineering, science, and agriculture. For such an analysis, it is essential to measure physical quantities such as temperature and velocity over the entire thermal flow field. This paper presents a measurement system based on color image processing for temperature and velocity vector distributions in a three-dimensional thermal flow field. Flow visualization is accomplished by the use of thermo-sensitive liquid crystal tracers. An algorithm for the color-to-temperature transformation using a multi-layer feed-forward neural network is applied to three-dimensional natural convection in a rotating cylindrical cell. Two-dimensional temperature distributions in a slit plane are obtained by using the algorithm. A three-dimensional temperature distribution is consequently constructed by interpolating the two-dimensional distributions using the B-spline function. In addition, the Spatio-Temporal correlation method is applied to the natural convection to obtain a three-dimensional velocity vector distribution. 相似文献
2.
Oxime-based salen-type tetradentate ligands with high stability against imine metathesis reaction 总被引:2,自引:0,他引:2
Akine S Taniguchi T Dong W Masubuchi S Nabeshima T 《The Journal of organic chemistry》2005,70(5):1704-1711
Although salen and its analogues are versatile chelate ligands in inorganic and organometallic chemistry, synthesis of unsymmetrical salen derivatives consisting of two different salicylideneimine moieties is difficult because of the C=N bond recombination. To develop stable analogues of salen-type ligands, we synthesized a series of new ligands salamo (=1,2-bis(salicylideneaminooxy)ethane) on the basis of O-alkyl oxime instead of the imine moiety. Eight salamo ligands 1a-h were prepared in 64-88% yields as colorless crystals from the corresponding salicylaldehydes 2a-h. The crystal structure of 1a-c suggests that the oxime-OH form is more predominant than the keto-NH form. The reaction of 2a-e with excess 1,2-bis(aminooxy)ethane gave monooximes 3a-e in 59-86%, which further reacted with a different salicylaldehyde to afford unsymmetrical salamo ligands 4-8 as stable crystals in 51-70%. No reaction took place when a mixture of salamo derivatives 1a and 1b was treated at 40 degrees C in H2O/MeCN (5:95). However, the metathesis reaction of salen derivatives 9a and 9b completed in 2 h to give a statistical mixture. Monooxime 3b was much more stable than monoimine 11 which is difficult to be isolated. These results indicate the extremely high stability of the salamo derivatives 1 and precursors 3. 相似文献
3.
Oludotun A. Phillips Eduardo L. Setti Andhe V. N. Reddy Ronald G. Micetich Chieko Kunugita Akio Hyodo Samarendra N. Maiti 《Chemistry of Heterocyclic Compounds》1998,34(11):1319-1323
Two monobactam derivatives, potassium 4-methyl-(3E)-[(thien-2-yl)methylene]-2-azetidinone-1-sulfonate and its (3Z)-isomer, were prepared and evaluated for their -lactamase inhibitory activities. These compounds were devoid of -lactamase inhibitory activity.SynPhar Laboratories Inc., #2, 4290-91A Street, Edmonton, Alberta T6E 5V2, Canada. Tokushima Research Institute, Taiho Pharmaceutical Co., Ltd., 224-2 Ebisuno Hiraishi, Kawauchi-cho, Tokushima 771-01, Japan. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1548–1552, November, 1998. 相似文献
4.
The bis(dibutylstannylene) derivative of 1,2-cyclohexylidene-myo-inositol reacted with (S)-O-acetylmandeloyl chloride and diphosphate tetraesters to give 3,6-dimandelate and 3-phosphate, respectively. Using the stannylene methodology for the optical resolution and regioselective phosphorylation of the ketal, a concise synthesis of phosphatidylinositol with the natural configuration was accomplished. 相似文献
5.
Ando M Takizawa M Suwabe S Yamato S Shimada K 《European journal of mass spectrometry (Chichester, England)》2003,9(6):619-622
Analysis of selenium in biological samples is very important and numerous analytical methods for the element have been developed. One of the most convenient and widely used methods for routine determination of serum selenium is a fluorometric method using 2,3-diaminonaphthalene (DAN); however, this method lacks specificity. We observed that 4,5-benzopiazselenol (BPS), a selenium derivative of DAN, is ionized with electron capture in an atmospheric pressure chemical ionization (APCI) interface, and subsequently established a method for determining total human serum selenium by means of liquid chromatography/atmospheric pressure chemical ionization mass spectrometry. All pretreatment procedures were carried out in a single test tube to minimize selenium loss. The recovery of organic or inorganic selenium spiked to human serum was 97-103%.The detection limit of BPS was equivalent to 0.2 ng of selenium and the lower quantitative limit of serum selenium was 10 ng mL(-1). The coefficient of variation of standard concentrations in control serum samples was 4.5%. The purity of the observed peak obtained from serum samples was confirmed using the ion cluster technique. 相似文献
6.
Masayuki Kirihara Takuya Noguchi Nobuhiro Okajima Sayuri Naito Yuki Ishizuka Aiko Harano Hiroyuki Tsukiji Ryu Takizawa 《Tetrahedron》2012,68(5):1515-1520
The reaction of dithioacetals with 30% hydrogen peroxide in the presence of catalytic amounts of tantalum(V) and iodide ion effectively produced carbonyl compounds in high yields. Dithioacetals also can be deprotected using the niobium(V) catalyzed oxidation of iodide ion by hydrogen peroxide under mild conditions. 相似文献
7.
Nallusamy Venkatachalam Eva Hemmer Tomoyoshi Yamano Hiroshi Hyodo Hidehiro Kishimoto Kohei Soga 《Progress in Crystal Growth and Characterization of Materials》2012,58(2-3):121-134
Yttrium hydroxyl carbonate (Y(OH)CO3) precursors were synthesized by the homogeneous co-precipitation method in the presence of polyacrylic acid (PAAc). Resultant precursor particle size is about 15–20 nm with narrow size distribution whereas the particle size is smaller than those acquired by the conventional homogeneous precipitation method. Effective decrease of Y(OH)CO3 particle size was found to be higher for the presence of weak polyanionic ionomer such as PAAc than the presence of strong polyanionic ionomer such as sodium polystyrene sulfonate (PSS). It was observed that the morphology and size of the precursors are almost unchanged after the calcination process. Er3+ doped Y2O3 nanoparticles were synthesized by PAAc assisted homogeneous co-precipitation method showed bright green (550 nm) and red (660 nm) upconversion (UC) as well as near-infrared (NIR) fluorescence (1550 nm) under 980-nm excitation. UC and NIR fluorescence bioimaging and in-vitro cytotoxicity assay of Er3+ doped Y2O3 nanoparticles were successfully attempted with commercially available macrophages and B-cell hybridomas. Cellular uptake of nanoparticles is evidenced from bright field, UC and NIR fluorescence images of macrophages. 相似文献
8.
Cover Picture: Development of Double‐Perovskite Compounds as Cathode Materials for Low‐Temperature Solid Oxide Fuel Cells (Angew. Chem. Int. Ed. 48/2014)
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