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排序方式: 共有283条查询结果,搜索用时 15 毫秒
61.
A novel ethyl 5-cyano-6-hydroxy-2-methyl-4-(1-naphthyl)-nicotinate is successfully synthesized and the structure is determined by XRD, GC-MS analysis, element analysis and NMR spectroscopic in detail. A reaction mechanism for the reaction is proposed.  相似文献   
62.
Abstract

Three kinds of betaine-type polymers, which are macromolecular amphoteric electrolytes, were found to be able to polymerize vinyl monomers in aqueous solution through a radical mechanism without any further initiator. Betain-type polymers form hydrophobic areas (HA) in water. Vinyl polymerization commenced in the HA. The effect of the pH of the aqueous solution on polymerization was investigated.  相似文献   
63.
Furui  Zhang  Ping  Ruan  Junfeng  Han 《Optical Review》2020,27(6):447-454
Optical Review - Point ahead angle (PAA) prediction is important in space laser communication, but the existing methods have low accuracy and complicated calculation processes. In this paper, a new...  相似文献   
64.
The molecular chain orientation of mercerized cellulose II was examined by optical second harmonic generation (SHG) measurements. The SHG intensities of several kinds of mercerized cellulose II were found to be much larger than those expected for a structural model with an antiparallel molecular chain orientation as proposed by X-ray studies. This result suggests that the orientation of mercerized cellulose II is parallel as suggested by molecular dynamics simulation. © 2004 The Optical Society of Japan  相似文献   
65.
This paper provides a formal framework within which to study cooperative behavior in the presence of incomplete information, and shows how far the known results in the static cooperative game theory can readily be applied to the proposed framework. The new concepts of Bayesian society, Bayesian strong equilibrium and Bayesian incentive compatible strong equilibrium are introduced and studied.  相似文献   
66.
Steam explosion pretreatment of potato for the efficient production of alcohol was experimentally studied. The amount of water-soluble starch increased with the increase of steam pressure, but the amounts of methanol-soluble material and Klason lignin remained insignificant, regardless of steam pressure. The potatoes exploded at high pressure were hydrolyzed into a low molecular liquid starch, and then easily converted into ethanol by simultaneous saccharification and fermentation using mixed microorganisms: an amylolytic microorganism,Aspergillus awamori, and a fermentation microorganism,Saccharomyces cerevisiae. The maximal ethanol concentration was 4.2 g/L in a batch culture at 15 g/L starch concentration, and 3.6 g/L in a continuous culture fed the same starch concentration. In the fed-batch culture, the maximal ethanol concentration increased more than twofold, compared to the batch culture.  相似文献   
67.
Detection of pollutants is of significant importance for environmental protection. However, conventional monitoring methods are often time-consuming, and require expensive equipments. Biosensors based on enzyme linked immunosorbent assay (ELISA) provide an alternative method to conventional ones. In this research, the reduction in the size of ELISA utilizing micro-chemical reaction is described in a micro-flow immunosensor chip. The immunosensor chips were fabricated by micro-electromechanical system (MEMS) technology. The quantitative determination of coplanar polychlorinated biphenyls (Co-PCBs) was performed by using a micro-flow immunosensor chip. Polystyrene beads were used as the solid substrate for the immobilization of Co-PCB antibody. The antibody-immobilized beads were introduced into the flow channel. As a competitive ELISA, sample solution mixed with horseradish peroxidase (HRP) conjugated antigen, and non-HRP conjugated antigen was allowed to react in the flow channel. After the antigen-antibody reaction, addition of phosphate buffer solution containing hydrogen peroxide and the fluorogenic substrate produced a fluorescent dye, which was monitored with the resulting change in the fluorescence intensity. By using our micro-flow immunosensor chip, it was possible to determine the sensing range of Co-PCB derivatives up to 0.1 ppt in 30 s. This immunosensor chip had a wide linear range for Co-PCB detection from 0.1 pg/ml to 1.0 μg/ml. The regression analysis provided the correlation coefficients of r = 0.982−0.964 with good reproducibility and precision. In a series of five measurements with immunosensor chips prepared with a new batch of antibody-immobilized polystyrene beads, a relative standard deviation of 21.3% was obtained. Our immunosensor chip design reported here has the potential to be implemented to several different detection methodologies for numerous analytes.  相似文献   
68.
The syntheses of polylactides (PLAs) with branched peptide end groups containing reactive (ionic) moieties such as amino or carboxyl groups are described and were used to prepare PLA‐based microspheres (MSs) with positively or negatively charged surfaces. Branched peptides with hydroxyl end groups and four protected amino or carboxyl groups, Boc4‐K3‐OH or Bn4‐E3‐OH, were synthesized, and the hydroxyl group converted to an alkoxide and was used as the initiation site for the ring‐opening polymerization of L ‐lactide. Subsequent deprotection gave PLAs end‐capped with branched peptides having four amino or carboxyl groups, respectively (K3‐PLA and E3‐PLA). K3‐PLA and E3‐PLA were converted to K34+‐PLA and E34?‐PLA by acid or base treatment, respectively. MSs with charged surfaces were then prepared using K34+‐PLA or E34?‐PLA as a surfactant [MS(K34+‐PLA) or MS(E34?‐PLA)]. The ionic surface state of the MSs was confirmed by colloidal titration and zeta potential analysis.

SEM image of MSs: MS(K34+‐PLA).  相似文献   

69.
1,8,13-Trialkyl(aryl)silyl-9-hydroxytriptycenes (trisilyltriptycenes) were synthesized by the triple addition of ynolates and 3-silylbenzynes with high regioselectivity. Benzene rings in the resulting triptycenes were highly distorted where the dihedral angles between the substituents were as high as 35°. The distortion energy induced step-by-step halogenation reactions to yield halogenated triptycenes, including chiral triptycenes. The 1,8,13-trihalogenated triptycenes were then converted to 1,8,13-functionalized triptycenes.  相似文献   
70.
Styrene(St) was polymerized in benzene solution in the presence of l, 3:2, 4:5, 6-trimethylene-D-sorbitol(TCA) by means of photo-irradiation of system at 30°C. It was found that the polymerization was depressed by the addition of TCA and then proceeded through a radical mechanism. The chain-transfer constant of the styryl radical to TCA was estimated to be 0.16. Accordingly, the photopolymerization of St in the presence of TCA is studied kinetically with regard to chain transfer and termination.  相似文献   
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