Authors:Fang Wang, Lin Zhou, Jiahong Zhou, Xiaotian Gu, and Yuying Feng
Hypocrellins, natural photosensitizers including hypocrellin A (HA) and hypocrellin B (HB), have been used as a traditional
Chinese herbal medicine to cure various skin diseases. Hypocrellins have excellent antiviral activity, which can inhibit the
growth of human immunodeficiency virus. They also exhibit significant light-induced antitumor property. In this article, thermal
analysis technologies (e.g., differential scanning calorimetry and thermogravimetry) are employed to characterize whether the photosensitive hypocrellin
A could be encapsulated with silica nanoparticle (SN) material or not, and evaluate the stability of inclusion complex. The
results show that the inclusion complex exhibits improved performance in both stability and hydrophilicity than natural hypocrellin
A. Fluorescence spectrophotometry studies have also been performed to verify the thermal analysis results. The results suggest
that the thermal analysis technology could be used as an effective and rapid tool to characterize the encapsulation properties
of the novel anticancer HA–SN complex.
Authors:Zu-Ming Zhou, Ying-Jie Zhang, and Hui-Fang Du
The kinetics of oxidation of U(IV) in nitric acid solution by nitrous acid and air oxygen have been studied. The effects of concentrations of U(IV), nitric acid, hydrogen ion and nitrous acid in aqueous solution or oxygen in gas on the oxidation rate have been examined. The oxidation rate increases with increasing temperature and the activation energies are 47 kJ mol–1 for nitrous acid and 91 kJ mol–1 for oxygen. The mechanisms for both oxidation reactions are discussed.
Authors:Xian-Bo Sun, Hui-Fang Du, Zhu-Xian Yang, and Zu-Ming Zhou
The kinetics of solvent extraction of U(VI) with di(2-ethylhexyl) phosphoric acid (HDEHP) using a microporous hydrophobic hollow fiber membrane extractor has been investigated. The effects of U(VI) and hydrogen ion concentrations in aqueous phase, HDEHP concentration in organic phase, flow velocities of aqueous and organic phase and temperature on extraction rate of U(VI) were examined. The experimental results suggest that the extraction rate of U(VI) is controlled by diffusion.
Authors:Yang Xing-Lu, Bao Bo-Rong, Zhou Fang, Cao Wei-Guo, and Li Yu-Lan
A novel extractant, N, N-didecanoylpiperazine (DDPEZ), was synthesized for the first time. The extraction of U(VI) by DDPEZ from aqueous nitric acid media in carbon tetrachloride has been studied. The dependence of extraction distribution ratio on concentration of aqueous nitric acid, extractant, salting-out agent and temperature was investigated and the enthalpy of the extraction was calculated.
Authors:Y. Xiong, D. Xu, Z. Chai, X. Li, Q. Tian, H. Zhou, W. Luo, and X. Fang
The paper presents the results of determination of extractable organohalogens (EOX) by instrumental neutron activation analysis
(INAA), and polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) by gas chromatography (GC), in atmospheric
precipitation in Shanghai, China, from January to August 2005. The results showed that EOCI was the major component of organohalogens
in precipitation. A significant correlation between the concentrations of EOBr and EOI was observed (r2 = 0.75), which suggested that EOBr and EOI in precipitation might mainly come from the same sources. There were no clear
seasonal trends for the concentrations of EOX. The concentrations of ΣPCBs ranged from 0.2–2.8 ng/l, with the dominant PCBs
containing 3 to 5 chlorine atoms. HCH was the predominant pesticide in precipitation, accounting for over 80% of total OCPs,
in which β-HCH took 28%–72% of total HCH. Also, there may be an evidence for significantly historical usage of DDT.
Authors:You-Shao Wang, Ai-Ping Yang, Ge-Fei Zhou, and Xu-Fang Tan
Five kinds of solid coordination complexes of uranium(VI) and thorium(IV) with the diamide (N,N,N,N-tetrabutylmalon-amide (TBMA), N,N,N,N-tetrabutylsuccinylamide (TBSA), N,N,N,N-tetrabutylglutaramide (TBGA), N,N,N,N-tetrabutyl-adipicamide (TBAA)) were synthesized. All these complexes of UO2(NO3)2·TBMA, UO2(NO3)2· TBSA, [UO2(NO3)2·(TBGA1/2)2]x, UO2(NO3)2·TBAA and Th(NO3)4·2TBMA were characterized by elemental analysis, UV spectra, IR spectra and 13C NMR spectra. The coordination form and proposed structures of the complexes are also discussed.
Authors:Shen Shuifa, Li Yan, Shi Shuanghui, Gu Jiahui, Liu Jingyi, Fang Keming, and Zhou Jianzhong
The decay of 101Mo to levels in 101Tc has been studied using the three-parameter (--t) coincidence system of HpGe-HpGe detectors. According to the coincidence data, the decay scheme was modified. The positions of 221.80, 318.00, 377.90, 452.50, 515.42, 1011.05 and 1759.72 keV transitions have been arranged again, the transition positions of 104.70, 105.95 and 774.15 keV gamma-rays have been assigned for the first time, the positions of 169.00, 590.91, 980.52 and 1431.68 keV transitions have been reconfirmed, the 1508.01 keV gamma-ray was observed simultaneously for the first time and its transition position has been assigned. The -intensities and the values of log ft of most levels were calculated.
Six lanthanide compounds [Ln(H2O)9](m-BDTH)3·9(H2O) where Ln = La (1), and [Ln(H2O)8](m-BDTH)3·9(H2O) (m-BDTH2 = 1,3-benzeneditetrazol-5-yl) where Ln = Lu (2), Yb (3), Er (4), Ho (5) and Y (6) were hydrothermally synthesized and characterized by elemental analyses, infrared spectra, powder X-ray diffraction (PXRD) and X-ray single crystal diffraction. PXRD indicates that 2–6 are isomorphous. Structural analyses reveal that 1 is coordinated by nine water molecules forming a capped-square antiprism, while 2–6 are coordinated by eight water molecules forming a simple square antiprismatic geometry. Effects of water molecules on thermal stability were also discussed by thermogravimetric (TG), DSC, and PXRD under different temperatures. TG analyses suggest that 1 loses lattice and coordinated water molecules with no diacritical boundary, and 6 removes lattice water molecules first and then coordinated water molecules. DSC and PXRD further confirm the consequence.
Effects of KNO3, CeO2, Fe2O3, their mixture and their thermally treated mixture on the combustion reactivity of two coals, bituminous coal (BC) and high ash coal (HAC), were investigated by thermogravimetric analysis. The ignition performance, burnout performance and exothermic behavior were used to evaluate the catalytic effect. Moreover, the kinetic parameters were determined using the Coats–Redfern method. The results indicated that the activity sequence of the catalysts on BC relative to the ignition performance can be described as follows: the thermally treated mixture > the mixture > KNO3 > Fe2O3 > CeO2, and the activity sequence relative to the burnout performance is the same. The activity sequence of the catalysts on HAC relative to the ignition performance can be described as follows: the thermally treated mixture > the mixture > Fe2O3 > CeO2 > KNO3, and the activity sequence relative to the burnout performance is the same. The exothermic heats of catalyst-incorporating samples increased and the activation energies of the samples decreased.
Authors:Xu-Fang Tan, You-Shao Wang, Tai-Zhe Tan, Ge-Fei Zhou, and Bo-Rong Bao
N,N,N′,N′-tetrahexylsuccinylamide (THSA) was used for the extraction of U(VI) and Th(IV) ions from nitric acid media into
n-dodecane. Extraction distribution ratios of U(VI) and Th(IV) as a function of nitric acid concentration, extractant concentration
and temperature have been studied. It was found that THSA as a new extractant is superior in some aspects to TBP for extraction
of U(VI) and Th(IV). The extraction of nitric acid was also investigated. At low acidity, the main adduct of THSA and HNO3 is THSA·HNO3. THSA·(HNO3)2 and THSA·(HNO3)3 also formed at high acidity. The composition of the species, equilibrium constants and enthalpies of the extraction reactions
have also been calculated. The suggested formation of the 1:2:1 ratio of uranyl(VI) ion and the 1:4:2 ratio of thorium(IV)
ion, nitrate ion and THSA as the extracted species was further confirmed by the IR spectra of U(VI) and Th(IV) extracts.