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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 objective of this study is to use a clustering algorithm based on journal cross-citation to validate and to improve the journal-based subject classification schemes. The cognitive structure based on the clustering is visualized by the journal cross-citation network and three kinds of representative journals in each cluster among the communication network have been detected and analyzed. As an existing reference system the 15-field subject classification by Glänzel and Schubert (Scientometrics 56:55–73, <cite>2003</cite>) has been compared with the clustering structure.

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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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Abstract  

Soybean oil based polyols (5-OH polyol, 10-OH polyol and 15-OH polyol) were synthetised from epoxidized soybean oil. The melting peak of polyols and the relationship between melting peak and the number-average functionality of hydroxyl in polyols were investigated by differential scanning calorimetry (DSC). The thermal decomposition of polyols and some of their thermal properties by thermogravimetry (TG) and derivative thermogravimetry (DTG) were also studied. The thermal stability of polyols in a nitrogen atmosphere was very close hence they had a same baseplate of triglyceride for polyols. The extrapolated onset temperature of polyols in their thermal mass loss, first step had a decreasing order: 5-OH polyol>10-OH polyol>15-OH polyol due to the difficulty in forming multiple elements ring of them had the same order. The thermal behavior of polyols under non-isothermal conditions using Friedman’s differential isoconversional method with different heating rates indicated that the 5-OH polyol had the lowest activation energy in thermal decomposition amongst these polyols according to the same fractional mass loss because of the weakest intramolecular oligomerization. The 15-OH polyol was prior to reach the mass loss region because the six-member ring is more stable than the three-member ring from 10-OH polyol and more easily formed.

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A space X is of countable type (resp. subcountable type) if every compact subspace F of X is contained in a compact subspace K that is of countable character (resp. countable pseudocharacter) in X. In this paper, we mainly show that: (1) For a functionally Hausdorff space X, the free paratopological group FP(X)and the free abelian paratopological group AP(X) are of countable type if and only if X is discrete; (2) For a functionally Hausdorff space X, if the free abelian paratopological group AP(X) is of subcountable type then X has countable pseudocharacter. Moreover, we also show that, for an arbitrary Hausdorff μ-space X, if AP 2(X) or FP 2(X) is locally compact, then X is a topological sum of a compact space and a discrete space.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Zhang Yuanxun
,
Lin Erhkang
,
Li Deyi
,
Wang Yinsong
,
Yu Yuehchung
,
Wang Changwan
,
Shen Waiguo
,
Zhi Min
,
Zhang Guilin
, and
Li Yan

Abstract  

In order to evaluate the evolution of contamination we collected river water and sediment samples in the every spring season since 1998. The elemental analysis of water and sediment samples was performed by PIXE using the 3×2 MeV NEC Tandem accelerator at the Taipei Institute of Physics. The characterization of - and -radioactive levels for water and sediment samples was performed by a BH1216, low background radioactivity instrument at the Shanghai Institute of Nuclear Research. The PIXE results showed that the elemental contents of Cl, K, Ca, Cr, Mn, Fe, Zn and Pb in river water gradually decreased with the rising tide. At high tide, their concentrations were minimum and then increased toward the ebb tide. The analysis also demonstrated that the radioactivity of water samples had been gradually decreasing year by year. It was found that the decreasing rate of -radioactivity was a little quicker than that of -radioactivity. Further aspects of environmental data evaluation and assessment are also discussed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors:
Chen Qingjiang
,
Su Shuxin
,
Guo Jinru
,
Yang Jingxia
,
Chen Yundong
,
Li Xueliang
,
Zhang Hongdi
,
Lin Fa
,
Sun Shuying
, and
Zhang Shulan

Abstract  

The distribution of mass in the spontaneous fission of252Cf has been investigated by the radiochemical determination of the absolute fission yields for 35 mass chains. A summation of the mass-yield curve gives a summed value of 199.4% which is in very good agreement with the value of 200% in fission. The mean masses of the light and heavy group are located at 106.39 and 141.82, respectively. The average number
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of neutron per fisson is 3.79±0.12. The peak-to-valley ratio is larger than 370. The width at one tenth of the maximum of the light and heavy group are 26.7 and 26.8 mass number, respectively. A comparison of previous investigators has resulted in recommended yields for 35 mass chains.
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Journal of Thermal Analysis and Calorimetry
Authors:
Jiawu Gao
,
Lin Li
,
Yanping Deng
,
Zongming Gao
,
Changhua Xu
, and
Mingxi Zhang

Abstract  

A new method for determining the degree of conversion of gelation (αgel) and gel time (t gel) at gel point using a single technology, DSC, is discussed in this work. Four kinds of thermoset resins are evaluated. It is found that the mutation points of reduced reaction rate (V r ) vs. reaction conversion (α) curves, corresponding with the changes of reaction mechanism, represents the gelation of the reaction. The α at the mutation point is defined as αgel. From isothermal DSC curves, the point at αgel is defined ast gel. Traditional techniques (ASTM D3532 and DSC method) are also used to determine αgel andt gel in order to demonstrate this new method. We have found that the results obtained from this new method are very consistent with the results obtained from traditional methods.

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