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791.
Ma B Chen Y Hao H Wu M Wang B Lv H Zhang G 《Colloids and surfaces. B, Biointerfaces》2005,41(2-3):197-201
Under the background of algae removal and growth inhibition by ultrasonic irradiation, the effects of ultrasonic irradiation on removal of Microcystis, the concentration variation of microcystins (MC) produced by Microcystis in Microcystis suspension, and sonochemical degradation of microcystins in water, were studied in the paper. The results showed that ultrasonic irradiation could efficiently inhibit the growth of Microcystis, and ultrasonic irradiation shorter than 5 min would not introduce the increase of microcystins dissolved in Microcystis suspension simultaneity. Also, microcystins dissolved in Microcystis suspension would not increase as ultrasonic power increasing. Further research showed that microcystins were effectively degraded in ultrasonic fields. After 20 min ultrasonic irradiation at 150 kHz and 30 W, the removal rate of microcystins reached 70%. 相似文献
792.
793.
The applicability of (1R,2R)-1,3-diacetoxy-1-(4-nitrophenyl)-2-propyl isothiocyanate [(R,R)-DANI] as a recently developed chiral derivatizing agent for the enantioseparation of a series of β-blockers is described. The thiourea diastereomers formed were analyzed by reversed-phase high-performance liquid chromatography, mixtures of water and methanol or acetonitrile being used for elution. Conditions of derivatizations (temperature, reagent excess and reaction time) were optimized, and the effects of organic modifiers on the retention and separation were investigated; the diastereomers could readily be baseline separated with methanol-containing mobile phases with resolutions between 1.58 and 2.72. 相似文献
794.
Novel synthesis of a strained para-cyclophane derivative 总被引:1,自引:0,他引:1
Zhi Hao Shi Yun Yang Wei 《中国化学快报》2007,18(4):397-399
A [P. Rajakumar, A.M.A. Rasheed, Tetrahedron 61(22) (2005) 5351] para-cyclophane derivative was synthesized via intramolecular esterification of a dipeptide surrogate containing asparagine to form tetrahydropyrimidinone ring. The structures of the product and intermediates were characterized by 1H NMR, 13C NMR and mass spectrum. 相似文献
795.
Uniform nylon 6 nanofibers with diameters around 200 nm were prepared by electrospinning. Polymorphic phase transitions and crystal orientation of nylon 6 in unconfined (i.e., as-electrospun) and a high T(g) (340 degrees C) polyimide confined nanofibers were studied. Similar to melt-spun nylon 6 fibers, electrospun nylon 6 nanofibers also exhibited predominant, meta-stable gamma crystalline form, and the gamma-crystal (chain) axes preferentially oriented parallel to the fiber axis. Upon annealing above 150 degrees C, gamma-form crystals gradually melted and recrystallized into the thermodynamically stable alpha-form crystals, which ultimately melted at 220 degrees C. Release of surface tension accompanied this melt-recrystallization process, as revealed by differential scanning calorimetry. For confined nanofibers, both the melt-recrystallization and surface tension release processes were substantially depressed; gamma-form crystals did not melt and recrystallize into alpha-form crystals until 210 degrees C, only 10 degrees C below the T(m) at 220 degrees C. After complete melting of nano-confined crystals at 240 degrees C and recrystallization at 100 degrees C, only alpha-form crystals oriented perpendicular to the nanofiber axis were obtained. In the polyimide-confined nanofibers, the Brill transition (from the monoclinic alpha-form to a high temperature monoclinic form) was observed at 180-190 degrees C, which was at least 20 degrees C higher than that in unconfined nylon 6 at approximately 160 degrees C. This, again, was attributed to the confinement effect. 相似文献
796.
This review aims to provide a summary of the progress in TP small molecule fluorescent probes for enzymes in recent years and displays the main fluorescent mechanisms that have been applied to design probes. 相似文献
797.
Teng-Yuan Dong Chienlin Huang Chiao-Pei Chen Ming-Cheng Lin 《Journal of organometallic chemistry》2007,692(23):5147-5155
We describe the formation of stable dithiol-bifunctionalized Ru(II)-terpyridine monolayer onto gold electrode. The coverage-dependent behavior onto gold electrode has been studied by electrochemical technique. The stability, surface charge coverage, and electron-transfer kinetics were assessed by cyclic voltammetry. Functionalized monolayer-protected Au clusters (MPCs) were also prepared. The spectroscopic characterization data of MPCs using UV-Vis and TEM techniques are discussed. TEM images showed that functionalized spherical nanoclusters of 4.7 ± 0.3 and 4.3 ± 0.2 nm were produced. The particle sizes are uniform with a narrow size distribution. The morphology of Au(1 1 1) metal surface modified with MPCs was imaged using atomic force microscopy (AFM). The nanoparticle layer exhibits a distinct surface morphology, irregularly shaped domains with dimensions from 20 to 60 nm and root mean square heights of 2.401 nm. 相似文献
798.
R.-L. Yun Y.-M. Chang C.-H. Lin K.-H. Hu C.-M. Shu 《Journal of Thermal Analysis and Calorimetry》2006,85(1):107-113
In industrial processes, information
on the safety property of chemicals is essentially crucial for safe handling
during unit operations. Ensuring the safe use of combustible or flammable
substances in processes is unlikely without detailed investigations of their
flammability characteristics and related hazards. We studied 3-methyl pyridine
(3-picoline), e.g., flammability limits (LFL/UFL), maximum explosion pressure
(P
max), maximum
explosion pressure rise (dP/dt)max, minimum oxygen concentration
(MOC), vapor deflagration index (K
g),
and characterized the influence of inert steam (H2O)
on critical parameters for 3-picoline/water mixtures at 270°C, 1 atm,
various oxygen concentrations, and vapor mixing ratios (100/0, 30/70, 10/90
and 5/95 vol.%) with a 20-L-Apparatus in simulated conditions, respectively.
The results showed that the flammability characteristics
of 3-picoline(aq) all increased with the oxygen concentration.
However, as the composition of inert steam increased, the flammability parameters
and the degree of fire and explosion hazards were significantly reduced, instead.
This study elucidated the flammability properties of 3-picoline mixed with
inert steam. The conclusions could be applied to proactively prevent the relevant
processes from incurring fire and explosion accidents. 相似文献
799.
In this paper, the chronoamperometry was used to study the charging processes of polyethylenedioxythiophene (PEDOT) modified electrodes in the potential range where PEDOT was in the oxidized state. The results show that the charging behaviors of the PEDOT films are well agreed with the exhausted finite diffusion model. The dependence of the capacitance values of the films on potential and concentration of solution was also studied in this potential range. 相似文献
800.
In this work, a new ligand, 2,9-bis[N,N-bis(carboxymethyl)-aminomethyl]-1,10-phenanthroline (BBCAP), was synthesized and
used to establish a novel fluorimetric method for the determination of trace amounts of terbium in a binary system. Its luminescence
mechanism was studied. The excitation and emission wavelengths are 284 nm and 547 nm, respectively. Other rare-earth metal
ions in 100-fold excess caused no interference. The fluorescence intensity was a linear function of the concentration of terbium
in the range of 5.0 × 10−10–1.0 × 10−6 mol/L. The detection limit was 2.0 × 10−11 mol/L (n = 12). The standard addition method was used to determine the terbium in a synthetic rare-earth sample with satisfactory
results. This method represents a direct, rapid, selective and sensitive analytical procedure with a widely linear range.
Received November 29, 2001 Revision February 9, 2002 相似文献