The simplified expressions for the electromagnetic field of the near zone from the magnetic frill are derived. In these formulas,E_{rho}andH_{phi}are expressed as a single integration of the complete elliptical integrals of the first and second kinds. Furthermore the closed form ofE_{z}is obtained approximately. Their accuracy is checked numerically by comparing with Tsai's, and significant improvement in efficiencies is obtained. 相似文献
Microporous carbons have been synthesized by the carbonization of cationic surfactant-resorcinol/formaldehyde (RF) composites, which were themselves formed by electrostatic organic-organic interaction. The porous structure produced by the decomposition of the surfactant plays an important role for the gasification of the RF polymer at higher temperatures. The pore size of the carbon prepared from tetrapropylammonium bromide (TPAB)-RF, cetyltrimethylammonium bromide (C16TAB)-RF and decyltrimethylammonium bromide (C10TAB)-RF mixtures can be estimated as 0.53 nm from the Horvath-Kawazoe method using N2 adsorption isotherms. Their pore size distributions were very narrow, showing that the microporous carbons derived from surfactant-RF mixture may have promise as adsorbents and membrane materials. 相似文献
Nitroalkyl acrylates and methacrylates involving some new compounds were prepared. The homopolymerization of these monomers in toluene and their copolymerization with styrene in acetone were carried out with azobisisobutyronitrile as initiator. The rate of polymerization of the nitroalkyl acrylates showed a correlation with the number of nitro groups situated on the ester side chain. The apparent activation energies of the polymerization were found to be 22.0–27.5 kcal./mole for the nitroalkyl acrylates and about 11.5–13.0 kcal./mole for the nitroalkyl methacrylates. From the reactivity ratios and Q-e values of the copolymerization the following information was obtained. The copolymerization behavior of nitroalkyl acrylates and methacrylates showed an alternating tendency, and these monomers belong to the conjugative monomer groups. On the reactivities of these monomers, the polarity of vinyl group was affected a little by nitro group of ester bond side, and the resonance affected little. These monomers were crosslinked with 2-methyl-2-nitro-1,3-propylene diacrylate. Some of the polymers showed marked improvement in the physical properties of elastomers. 相似文献
Epilepsy is a neurological disorder that may affect the autonomic nervous system (ANS) from 15 to 20 min before seizure onset, and disturbances of ANS affect R–R intervals (RRI) on an electrocardiogram (ECG). This study aims to develop a machine learning algorithm for predicting focal epileptic seizures by monitoring R–R interval (RRI) data in real time. The developed algorithm adopts a self-attentive autoencoder (SA-AE), which is a neural network for time-series data.
The results of applying the developed seizure prediction algorithm to clinical data demonstrated that it functioned well in most patients; however, false positives (FPs) occurred in specific participants. In a future work, we will investigate the causes of FPs and optimize the developing seizure prediction algorithm to further improve performance using newly added clinical data.
DNA machines consisting of consecutive hairpins, which we have previously described, have various potential applications in
DNA computation. In the present study, a 288-base DNA machine containing four consecutive hairpins was successfully constructed
by ligation and PCR. PAGE and fluorescence spectroscopy experiments verified that all four hairpins were successfully opened
by four opener oligomers, and that hairpin opening was dependent on the proper openers added in the correct order. Quantitative
analysis of the final results by fluorescence spectroscopy indicated that all four hairpins were open in about 1/4 to 1/3
of the DNA machines. 相似文献
The electrochemical activation process of the so-called “alkali-treated soft carbon” (ASC) has been examined in organic electrolyte solutions. SEM observation demonstrated that the edge plane of graphene structure of the ASC particle becomes rough after the activation, and XRD measurements indicated that the average lattice constant of graphene stacking in ASC increases after the activation process. Ex-situ 7Li NMR measurements proved that the insertion of cation (Li+) into the pore structure of ASC is associated with the activation process in the electrolyte dissolving Li salt. The pore-size distribution determined from N2-gas adsorption for ASC electrodes before and after the electrochemical activation indicates that the pore structure becomes developed after the electrochemical polarization, especially in the pore-diameter range of 2–10 nm. A schematic model of the activation process has been presented, which includes electrochemical insertion of ions into the inside of the ASC. 相似文献
Preparation of hard palm midfractions (PMF) and its use as a cocoa butter equivalent ingredient were studied. Hard PMF is
obtained by multistep fractionation of palm oil involving dry fractionation (DF) and/or solvent fractionation (SF), usually
using hexane or acetone. From our experience, in acetone, a polar solvent, symmetrical 1,3-disaturated triacylglycerols tend
to selectively crystallize more than nonsymmetrical 1,2- or 2,3-disaturated triacylglycerols, making it suitable for obtaining
the solid midfraction. Unfortunately, triacylglycerols are very soluble in hexane, and temperatures at least 15 degrees lower
than those required for acetone must be used for equivalent crystal yields. On the other hand, DF is a less expensive and
safer process. Thus, multistep fractionation combining DF and SF using acetone was developed to achieve sufficient removal
of high-melting components, and further enrichment of 1,3-dipalmitoyl-2-oleoylglycerol and the hard PMF was obtained by triple-step
fractionation of palm olein or double-step fractionation of soft PMF. Compared to conventional hard PMF, this hard PMF had
a steeper melting curve and better snapping and sharp-melting qualities when used in chocolate. Heat resistance of the hard
PMF chocolate was similar to the conventional hard PMF chocolate, and its bloom resistance could be improved by adding polyglycerol
fatty acid esters. 相似文献
Melt pool behaviour and the characteristics of the surrounding metal powder during selective laser melting (SLM) are captured using high-speed imaging, and the influence of the substrate temperature and the line building sequence on the formation of the built structure and the generation of spatter particles is experimentally investigated. The results indicate that the substrate temperature has a measurable effect on the formation of droplets and the generation of spatter particles, while the volume specific energy density of the process was the principal factor affecting the built structure. 相似文献
Reduction of cuprous chloride has been examined in various atmospheres, mostly at 600°C, to produce copper microfibers that can be applied as a filler for electromagnetic interference shielding and electron conductive paste composites. The reduction with hydrogen resulted in formation of a large amount of copper films, but fine particles and short filaments were obtained when carbon black was mixed into the raw material. The most promising copper microfibers with dimensions of several mm length and 1–10 m thickness could be produced with the system CuCl — C — H2O using argon as a carrier gas, where H2 and CO formed then probably reduced the vaporized CuCl molecules. Introduction of hydrogen gas into this system increased the yield of copper microfibers, though they became more bent, curved and kinked in shape. However, the morphology of the microfibers is still acceptable as a filler. 相似文献