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  • Author or Editor: Lin Zhang x
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Abstract  

In on—line measurement on sheet thickness by -ray transmission, for the sheet thickness vibrates in counting time, and attenuation of -ray which penetrates matter follows an exponential law, not a linear one. So the measured value of thickness which is taken from mean counting rate deviates from the true value.The paper analyses the causes of this deviation, describes the expression form of the dynamic error which is induced by these deviatons, gives a method to diminish the dynamic error by correcting the deviation.

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Abstract

Polymer-modified TiO2 was found to be a new, efficient photocatalyst for the photodegradation of organic pollutants. Another novel sensitizer-poly(fluorene-co-bithiophene) (PFB) was presented in this study. Varying the bithiophene content of PFB from 10, 20, 33, 40 to 50% in molar ratio, a series of copolymers (PFB10, PFB20, PFB33, PFB40 and PFB50) were prepared and used as the sensitizers for TiO2. The photodegradation rates of phenol catalyzed by these polymer-modified titanium dioxide composites under the irradiation of the GaN LED clusters were investigated. It was found that PFB33-modified TiO2 was the most efficient photocatalyst although the absorption spectrum of PFB50 was broader than that of PFB33.

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Abstract  

In order to determine the fission yields of lanthanides precisely, lanthanides with carriers of 1–2 mg per element are separated from each other by means of pressurized cation exchange chromatography-HIBA concentration gradient elution: The effects of initial loading technique, concentration gradient, flow rate, and temperature on separation were investigated in detail. Under the optimum conditions adopted according to the results given in this work, all the lanthanides can be completely separated within about 90 minutes with a recovery of more than 95% and purity higher than 99%.

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Abstract  

Zirconium in simulated high level radioactive liquid waste (HLLW) was selectively adsorbed and separated by self-made high adsorption activity silica gel. The selective adsorption mechanism was analyzed according to the structure character of self-made silica gel and performance of zirconium in acid simulated HLLW. The results show that the adsorption selectivity of self-made silica gel for zirconium is strong, because zirconium has higher positive charge and zirconium ion hydrolyzes easily. Distribution coefficient of self-made silica gels for zirconium is 53.5 ml/g. There are 6.5 (OH)/nm2 on the surface on self-made silica gels which provide more adsorption activity places, thus self-made silica gels have higher adsorption capacity for zirconium (31.4 mg/g). The elution rate of the adsorption of zirconium on self-made silica gel by 0.2 mol/l H2C2O4 is more than 99%. The solubility of the self-made silica gel in nitric acid is low, the chemical stability of self-made silica gel is very strong.

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Abstract  

A new ecomaterial, zirconyl molybdopyrophosphate (ZMPP), was prepared by a coprecipitation method. The removal of Cs+ and Sr2+ ions from simulated strong acid HLLW using the ion exchange process on ZMPP had been investigated. It showed that there are more than 90% Cs+ and Sr2+ removed from the simulated HLLW on ZMPP despite the presence of other metal ions, such as Na+, Al3+, Fe3+, etc. in excess. Then ZMPP may likely be a selective ion exchanger for the removal of 137Cs and 90Sr directly from strong acid HLLW.

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Summary  

The elastic scattering cross sections of natural vanadium for protons have been measured for beam energies below 2.64 MeV in steps of 10 keV and in the angular 160° and 170°. The overall standard error (ΔσExpExp) in the measured cross sections is estimated to be better than ±3% at all the beam energies and angles. The results are presented in graphical and tabular forms that should be useful for those who wish to use the cross sections for material analysis.

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Abstract

Two linear triblock copolymers poly(t-butyl methacrylate-b-2-hydroxyl ethyl methacrylate-b-N,N-dimethylaminoethyl methacrylate) (PtBMA97-b-PHEMA18-b-PDMAEMA98) and poly(t-butyl methacrylate-b-glycidyl methacrylate-b-styrene) (PtBMA137-b-PGMA23-b-PSt156) were controlled synthesized with living RAFT polymerization technique under the chain transfer of cumyl dithiobenzoate. The results of FT-IR spectra illustrate that the characteristic groups of copolymer fit well with the result of 1H-NMR, which successfully determines the corresponding molecular structure of triblock copolymers. The thermal stability of PtBMA-b-PGMA-b-PSt and PtBMA-b-PHEMA-b-PDMAEMA was also complementarily explained by the activation energy of thermal decomposition from Friedman differential method and Ozawa–Flynn–Wall integral method. The results show that the degradation energy of the former copolymer was much higher than that of the latter copolymer, because the aromatic groups were introduced into the polymer segments of the former copolymer during the RAFT polymerization process, and the other reason is the oxirane rings are typically reactive which they occurred intermolecular crosslinking reaction during the thermal decomposition.

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Abstract  

This paper reports the applications of INAA in analysis of Chinese ancient porcelain fired from early Northern Song dynasty (AD 1004–1127) to Late Yuan dynasty (AD 1320–1368) in Hutian Kiln. Minor and trace elements of 168 pieces of ancient porcelain bodies were determined by INAA. The results of factor analysis and some archaeological questions are also discussed in this paper.

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Abstract  

The kinetics of99mTc-d, 1-HMPAO decomposition is studied using home kits. The results showed that99mTc-d, 1-HMPAO decomposition is a first-order reaction. The decomposition constant k is found to be 0.017±0.007h–1 under the experimental conditions of 20°C, 185MBq/ml, pH 7.0. The stability of99mTc-d, 1-HMPAO is affected not only by pH and radioactive concentration, but also by temperature. Using Immol/l gentisic acid as a stabilizer, 740MBq/ml of99mTc-d, 1-HMPAO can be stabilized for 3h with the radiochemical purity above 80%.

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Abstract  

Monoclonal antibody 3H11 was labelled with99mTc by modified Schwartz method. The antibody was incubated in a glass test tube at room temperature for 30min with a 1000-fold molar excess of 2-mercaptoethanol. The mean labelling efficiency of 3H11 with99mTc was more than 95%. The immuonreactivity of99mTc-3H11 was more than 80% by ELISA's method. Competetion results in vitro and HPLC analysis showed that99mTc was combined at the high affinity sites of antibody. The biodistribution in nude mice bearing 823 gastric cancer xenograpfts showed that the radioactivity in tumor at 24h postinjection was the highest except for that in kidney. The tumor uptake was 8.98±2.42% i.d/g. The ratio of tumor to blood was over 1.5 and that of tumor to liver was more than 2.5 at 24h post-injection. The tumor was clearly imaged at 22h postinjection. The inital clinical results showed that99mTc-3H11 was stable in vivo and was good located at the lesion sites.

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