Search Results

You are looking at 1 - 10 of 54 items for

  • Author or Editor: P. Liu x
Clear All Modify Search

Abstract  

Weak atomic decompositions of B-valued martingales with two-parameters in weak Hardy spaces w pΣα and w p H α are established and the boundedness of sublinear operators on these spaces are proved. By using them, some characterizations of the smoothness of Banach spaces are obtained.

Restricted access

Abstract  

Serials of halloysite nanotubes/polystyrene (HNTs/PS) nanocomposites with different contents of organo-modified halloysite nanotubes (organo-HNTs) were successfully prepared by the in situ bulk polymerization of styrene with the organo-HNTs as macromonomers. The percentage of grafting (PG%) of more than 230% was achieved, calculated from the results of the thermogravimetric analysis (TG). The TG results also showed that the thermal stabilities of the HNTs/PS nanocomposites prepared via the bulk polymerization were better than the pure polystyrene. And the maximum thermal degradation temperature of the nanocomposites increased with the increasing of the amount of the HNTs fillers added.

Restricted access

Abstract  

This paper deals with a rapid method to determine radionuclides in reactor coolant by anion, cation, and anion-cation exchange membranes. A high pressure filtration device was established to simulate the THOR cooling water sampling system by means of several membranes mentioned above. The experimental results indicate that the adsorption efficiency of each membrane for several radionuclides is /1/ >95% with cation exchange membrane for Zn, Co, Na, Mn, Cu, Cs, Ba, La, W etc., /2/ >98% with anion exchange membrane for I, and /3/ <98% with anion-cation exchange membranes for Fe and Cr. The results are obtained using cooling water of Tsing Hua Open-Pool Reactor and the following radionuclides were identified:99mTc,140Ba,140La,51Cr,131I,58Co,60Co,54Mn,46Sc,59Fe,24Na, etc.

Restricted access

Abstract  

The concentrations of hydrogen peroxide formed in the coolant due to radiolysis were studied during THOR operation at 1 MW. The relation between doses and hydrogen peroxide formation in a neutron-gamma mixed field was investigated. The initial concentration was 2.3×10–5 g/ml at the beginning of reactor operation, and then it was increased rather rapidly at the first 9 h. The increasing rate was slowed down till the end of 30 h operation. The maximum concentration of hydrogen peroxide was found to be 4.7×10–5 g/ml, and its decrease followed the exponential curve.

Restricted access

Abstract  

Several interpolation theorems on martingale Hardy spaces over weighted measure spaces are given. Our proofs are based on the atomic decomposition of martingale Hardy spaces over weighted measure spaces. As applications of interpolation theorems, some inequalities of martingale transform operator are obtained.

Restricted access

Triclocarban (TCC) and triclosan (TCS) are used in a wide range of household and personal care products and have been the most frequently detected organic pollutants in both wastewater and surface water. This paper presented a rapid analytical method for simultaneous determination of TCC and TCS in wastewater. The method involves the extraction and cleanup of the target compounds by using silicon dioxide/polystyrene composite microspheres solid-phase extraction and detection with ultra-high-pressure liquid chromatography. Under the optimized conditions, the limits of detection were 0.028 μg/L and 0.040 μg/L for TCC and TCS, respectively. Under the concentrations of the spiking level ranging from 0.100 μg/L to 2.000 μg/L, the spiked recoveries of TCC and TCS in wastewater samples achieved in the range of 89.5–102.8% with RSD below 6.3% for TCC and 95.5–103.6% with RSD below 6.9% for TCS. This method was successfully used in monitoring the water samples from three traditional wastewater treatment plants.

Restricted access

Abstract  

The application of a microcalorimetric method to the study of extremophiles is described briefly. Using the LKB 2277 Bioactivity Monitor, the growth thermogenic curves of three strains of Halobacterium halobium were determined at 37C, and compared with the spectrophotometric curves. Then the suitable growth thermokinetic equation was established based on the characteristics of growth thermogenic curves. By using cycle-flow method, all of the growth thermogenic curves of H. halobium strains displayed a brief lag phase before the onset of exponential growth when they were cultured in Halo-2 medium.

Restricted access

The essential oil extracted from Nardostachys chinensis Batal (NCB) was analyzed by gas chromatography-mass spectrometry (GC-MS) combined with two chemometric resolution methods (CRM), heuristic evolving latent projections (HELP), and selective ion analysis (SIA). Qualitative analysis was performed by comparing the obtained pure mass spectra with those in National Institute of Standards and Technology (NIST) mass spectra database. Identification of some compounds was assisted by comparison of programmed temperature retention indices (PTRIs). The quantitative results were obtained by overall volume integration (OVI). A total of 69 compounds in the essential oil of N. chinensis Batal were identified, accounting for 93.98% of the total content. The major compounds were (−)-spathulenol, epiglobulol, trans-longipinocarveol, and patchouli alcohol which contribute to the antimicrobial and antioxidant activity. The results showed that the efficiency and reliability were greatly improved by use of chemometric techniques and programmed temperature retention index as assistants of GC-MS in identification of the plant essential oil.

Open access

Abstract  

A solid complex of rare-earth compounds with alanine, [ErY(Ala)4(H2O)8](ClO4)6 (Ala=alanine), was synthesized, and a calorimetric study and thermal analysis for it was performed through adiabatic calorimetry and thermogravimetry. The low-temperature heat capacity of [ErY(Ala)4(H2O)8](ClO4)6 was measured with an automated adiabatic precision calorimeter over the temperature range from 78 to 377 K. A solid-solid phase transition was found between 99 and 121 K with a peak temperature at 115.78 k. The enthalpy and entropy of the phase transition was determined to be 1.957 Kj mol-1, 16.90 j mol-1 k-1, respectively. Thermal decomposition of the complex was investigated in the temperature range of 40~550C by use of the thermogravimetric and differential thermogravimetric (TG/DTG) analysis techniques. The TG/DTG curves showed that the decomposition started from 120 and ended at 430C, completed in three steps. A possible mechanism of the thermal decomposition was elucidated.

Restricted access

Abstract  

A microcalorimetric technique based on the bacterial heat-output was explored to evaluate the effect of Mn(II) on Bacillus thuringiensis. The power-time curves of the growth metabolism of B. thuringiensis and the effect of Mn(II) on it were studied using an LKB-2277 BioActivity Monitor, ampoules method, at 28C. For evaluation of the results, the maximum peak-heat output power (P max) in the growth phase, the growth rate constants (k), the log phase heat effects (Q log ), and the total heat effect in 23 h (Q T) for B. thuringiensis were determined. Manganese has been regarded as the essential biological trace element. Mn(II) of different concentration have different effects on B. thuringiensis growth metabolism. High concentration (800-1600 μg mL-1) of Mn(II) can promote the growth of B. thuringiensis; low concentration (500-800 μg mL-1) can inhabit its growth.

Restricted access