共查询到20条相似文献,搜索用时 757 毫秒
1.
A small molecule (GMS-SA2) with one alkyl chain and two terminal carboxyl groups was synthesized successfully by the reaction of glyceryl monostearate
(GMS) with excess succinic anhydride (SA). Then, GMS-SA2 was used as a coupling agent to condensate with polyethylene glycols (PEG) of different molecular weight or polyethylene
glycol monomethyl ether (PEGm) in the presence of stannous octoate as catalyst and diphenyl ether as azeotropic agent. The
AB2 star-shaped miktoarm copolymers were obtained successfully and were characterized by 1H-NMR, DSC, GPC, XRD, FTIR and polarizing microscopy. The results of DSC and XRD measurements indicate that the crystallization
temperature and the melting temperature of the AB2 star-shaped miktoarm copolymers are different from those of the corresponding linear PEGs, because the existing of GMS-SA2 alters their crystalline growth velocity and the perfect degree of crystals. It is very important to control the crystal
morphology of star-shaped copolymers by introducing the miktoarm into the starshaped polymers and adjusting its content in
star-shaped polymers.
__________
Translated from Chemical Journal of Chinese Universities, 2007, 28(7): 1365–1370 [译自: 高等学校化学学报] 相似文献
2.
A. S. Vorokh N. S. Kozhevnikova A. A. Rempel A. Magerl 《Journal of Structural Chemistry》2010,51(6):1170-1175
Dense thin nanostructured films of cadmium sulfide CdS obtained by chemical deposition from aqueous solutions are strongly
bound to a substrate due to the formation of cadmium hydroxide Cd(OH)2 in the system. By X-ray reflectometry and grazing incidence diffraction it is found that at the beginning of the deposition
a dense Cd(OH)2/SiO2 layer is produced on the surface of a silicon or glass substrate. This layer is formed through the atomic-layer adsorption
of crystalline 1–3 nm thick Cd(OH)2 film by the oxygencontaining substrate surface. During sulfidation of this cadmium-containing substrate layer, a surface
nucleation layer of CdS/Cd(OH)2/SiO2 forms, which provides the growth, denseness, and strong adhesion to the substrate of nanostructured CdS film with a disordered
structure. According to the obtained experimental data, a “hydroxide scheme” of film deposition is confirmed and refined,
and the stages of CdS nanofilm formation are determined. 相似文献
3.
Guangjun Xu Wen Gu Xiaofang Ma Li Feng Shiping Yan Daizheng Liao Peng Cheng 《Frontiers of Chemistry in China》2008,3(2):138-142
The interaction between CT-DNA and a ternary copper (II) complex, [Cu(phendio)(L-Phe)(H2O)](ClO4)·H2O (CuPP, phendio = 1,10-phenanthroline-5,6-dione, L-Phe = L-phenylalanine), has been conducted by electronic spectra, fluorescence
spectroscopy and cyclic voltammetry. It has been found that the max. absorption peak from the electronic spectra is red shifted
and the intensity is weakened and that the values of peak current from cyclic voltammetry are decreased significantly in the
presence of DNA compared with that in the absence of DNA. At the same time, the complex can quench the emission intensity
of EB-DNA system. The existence of the intercalation mode between the complex and DNA was proven. By submarine gel electrophoresis,
we found that the copper(II) complex can cleave circular plasmid pBR322 DNA into nicked and linear forms in the presence of
ascorbic acid and H2O2.
__________
Translated from Acta Scientiarum Naturalium Universitatis Nankaiensis, 2007, 40(1): 32–36 [译自: 南开大学学报(自然科学版)] 相似文献
4.
The ZnO films with two-dimensional ordered macroporous structure were successfully fabricated through hydrothermal crystal
growth of ZnO on the ZnO substrate covered with a monolayer of polystyrene (PS) spheres as template. The precursor solution
of hydrothermal crystal growth of ZnO were prepared by equimolar solution of Zn(NO3)2·6H2O and hexamethylenetramine (HMT). The confinement effect of the PS spheres template on the growth of ZnO nanorods and the
influence of sodium citrate on the crystal growth of ZnO had been studied. The film surface morphology and the preferential
growth of ZnO crystal were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Also,
the photoluminescence spectrum of ZnO films had been measured, and the corresponding mechanism was discussed.
__________
Translated from Chemistry, 2007, 70 (8): 587–592 [译自: 化学通报] 相似文献
5.
Xianru Pei Xiaodong Wang Shunli Zhang Jingwei Zhang Jianjun Yang Zhensheng Jin 《Frontiers of Chemistry in China》2007,2(3):265-269
Nanotube Li-Ti-O compound with high surface (198.6 m2·g−1) was prepared by a method involving the treatment of nanotube Na2Ti2O5·H2O in molten LiNO3 and characterization by means of transmission electron microscopy (TEM), energy-dispersive spectra (EDS), X-ray diffraction
(XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetry-differential thermal analysis (TG/DTG). Results show that
the nanotube Li-Ti-O compound prepared by this method involves two crystal phases: spinel Li2Ti2O4 and anatase LixTiO2 (x < 0.1). Li+ exhibits different Li1s binding energy in the two crystal phases. In ambient air, the Li-Ti-O compound adsorbs water easily,
and the chemically adsorbed water is difficult to remove below 400°C.
Translated from Chinese Journal of Inorganic Chemistry, 2006, 22(12): 2135–2139 [译自: 无机化学学报] 相似文献
6.
ZrWMoO8 powders with different morphologies were obtained using ammonium tungstate, molybdate tungstate and zirconium tungstate as
the starting materials by dehydrating the precursor ZrWMoO7(OH)2(H2O)2. The precursor was studied by thermo-gravimetric and differential scanning calorimetry (TG-DSC). The influence of the gelling
agents (HCl, HClO4, HNO3, H2SO4 and H3PO4) on the crystallization process and crystal morphology of the products prepared was investigated by X-ray powder diffraction
(XRD), scanning electron micrograph (SEM) and X-ray fluorescence spectrometer (XRF). Results showed that the morphology of
the ZrWMoO8 particles can be simply adjusted by changing the gelling agents, and the thermal expansion coefficients of cubic ZrWMoO8 prepared in HCl solution are −3.84 × 10−6 K−1 from 100°C to 700°C.
__________
Translated from Chemical Journal of Chinese University, 2007, 28(3): 397–401 [译自: 高等学校化学学报] 相似文献
7.
A nano-alumina with high specific area was prepared using a homogeneous precipitation method with titanium dioxide and barium
oxide as modifying additives. Results showed that 5 wt% TiO2 or BaO added in the alumina gels can decrease the particle size and increase the specific area, but excessive TiO2 or BaO could deteriorate the properties of α-Al2O3.
__________
Translated from Journal of Shandong University of Technology (Natural Science Edition), 2007, 27(3): 23–26 [译自: 山东理工大学学报(自然科学版)] 相似文献
8.
Chun Yang Gongfeng Xu Bin Liu Qinglun Wang Daizheng Liao 《Frontiers of Chemistry in China》2008,3(3):294-297
The bimetallic complex of Ni2Co(TTHA)·12H2O (TTHA = triethylene tetraminehexaacetic acid) was synthesized and characterized structurally and magnetically. The title
complex crystallizes in the triclinic space group P ī with a = 0.7316(2), b = 0.8624(2), c = 1.5041(4) nm; α = 73.38(2), β = 83.97(2), γ = 70.50(2)°. The crystal structure is built up of [Ni2(TTHA)(H2O)2]2−, Co(H2O)62+ and water molecules. The variable magnetic measurement shows that there is strong antiferromagnetic interaction between two
Ni(II) ions in [Ni2(TTHA) (H2O)2]2− with J
Ni−Ni = −141.64 cm−1, g
Ni = 2.21 and that the constant of spin-orbit coupling of Co(II) ion is −134.8 cm−1.
__________
Translated from Acta Scientiarum Naturalium Universitatis Nankaiensis, 2007, 40(1): 6–10 [译自: 南开大学学报(自然科学版)] 相似文献
9.
A novel compound of butyl crystal violet lactone (BCVL) has been prepared by oxidizing leuco butyl crystal violet lactone
(LBCVL), which was obtained by the mixture of N,N-dibutylaniline, p-(dibutylamino) benzaldehyde and methyl-m-(dibutylamino) benzoate. The structure of BCVL was characterized by 1H-nuclear magnetic resonance (NMR), infrared (IR), and mass spectrometry (MS). The color of BCVL can change reversibly in
some acid or alkali solvents. The result of the dissolution experiment showed that solubility of BCVL in organic solvent was
improved compared with crystal violet lactone (CVL).
Translated from Journal of Fudan University (Natural Science), 2006, 45(3): 375–379 [译自: 复旦学报(自然科学版)] 相似文献
10.
The after effects of β− -decay on time differential perturbed angular correlation (TDPAC) spectra of II–VI semiconductor CdS have been studied using
β− -emitting111Ag as well as111mCd as probe nuclei. The TDPAC spectrum of111Ag in CdS exhibits a time dependent interaction indicating that the preceding β− -decay leaves the daughter nucleus in an excited state. The recovery time (τg) of the probe atom was found to be 16±6 ns while Abragam and Pound's relaxation time (τkr) was found to be 9±2 ns. The results show that β− -decay does change the chemical environment around the probe atom. 相似文献
11.
Sr2CeO4/Ln3+ (Ln = Er, Ho, Tm) phosphors were synthesized with the microwave radiation method for the first time. The luminescent properties
of the samples were investigated and the up-conversion luminescence of Er3+, Ho3+ and Tm3+ doped Sr2CeO4 phosphors was observed. The spectra indicate that the energy transfer takes place from the triplet excited state of MLCT
(metal-to-ligand charge transfer) state for Sr2CeO4 (sensitizer) to the rare earth ions (activator).
__________
Translated from Journal of Hebei Normal University (Natural Science Edition), 2007, 31(2): 212–216 [译自: 河北师范大学学报 (自然科学版)] 相似文献
12.
Xiaofeng Zhang Shen Lin Xinqing Chen Jiebo Chen Liuyi Yang Minghong Luo 《Frontiers of Chemistry in China》2007,2(4):419-421
Mesoporous aluminophosphate was prepared by using G4.0 poly(amido amine)dendrimer as a template and characterized by Fourier
transform infrared spectrometer (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption/desorption methods. Results show that the title compound exhibits a typical mesoporous structure with the average
pore size from 5 to 8 nm. The formation mechanism of the nanoporous structure using dendrimer as a template was also discussed.
__________
Translated from Journal of Fujian Normal University (Natural Science Edition), 2007, 23(2): 67–70 [译自: 福建师范大学学报 (自然科学版)] 相似文献
13.
Controlled/living photopolymerization of methyl methacrylate (MMA) in miniemulsion mediated by 4-hydroxy-2,2,6,6-tetramethyl-piperidinyloxy
(HTEMPO) was carried out at ambient temperatures. MMA miniemulsion was prepared by using an anionic surfactant with cetylalcohol
as a co-stabilizer. The photopolymerization led to stable lattices and they were obtained with no coagulation during synthesis
and no destabilization over time. It was found that the obtained MMA homopolymers exhibited relatively narrow molecular weight
distribution (PDI = 1.27 − 1.36) which was characterized by GPC. The plots of number-average molecular weight in (M
n) vs. conversion and ln([M0]/[M]) vs. time both were linear indicating that the reaction was a controlled/living free radical polymerization.
__________
Translated from Chemical Journal of Chinese Universities, 2007, 28(4): 774–778 [译自: 高等学校化学学报] 相似文献
14.
Kinetics of thermal decomposition of CeO2 nanocrystalline precursor prepared by precipitation method
Xiaolan Song Xi He Haiping Yang Dayu Xu Nan Jiang Guanzhou Qiu 《Frontiers of Chemistry in China》2008,3(2):182-185
The thermal decomposition of CeO2 nanocrystalline precursor prepared by chemical precipitation method was investigated using thermo-gravimetric/differential
scanning calorimetry (TG/DSC) and X-ray powder diffraction (XRD). In particular, the differential thermal analysis curves
for the decomposition of CeO2 nanocrystalline precursor were measured at different heating rates in air by a thermal analyzer (NETZSCH STA 449C, Germany).
The kinetic parameters of the thermal decomposition of CeO2 nanocrystalline precursor were calculated using the Kissinger method and the Coats-Redfern method. Results show that the
apparent active energy E of the reaction is 105.51 kJ/mol, the frequency factor lnA is 3.602 and the reaction order n is 2. This thermal decomposition process can be described by the anti-Jander equation and a three-dimensional diffusion mechanism.
Tanslated from Journal of Central South University (Science and Technology), 2007, 38(3): 428–432 [译自: 中南大学学报(自然科学版] 相似文献
15.
After preparing the precursor by a liquid precipitation method, a series of tin-zinc composite oxides with different components
and structures were synthesized as the anode materials for lithium ion batteries when the precursor was pyrolyzed at different
temperatures. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and electrochemical
measurements. The reversible capacity of amorphous ZnSnO3 is 844 mA · h/g in the first cycle and the charge capacity is 695 mA · h/g in the tenth cycle. The reversible capacity of
ZnO · SnO2 is 845 mA · h/g in the first cycle and the charge capacity is 508 mA · h/g in the tenth cycle. The reversible capacity of
SnO2 · Zn2SnO4 is 758 mA · h/g in the first cycle and the charge capacity is 455 mA · h/g in the tenth cycle. Results show that amorphous
ZnSnO3 exhibits the best electrochemical property among all of the tin-zinc composite oxides. With the formation of crystallites
in the samples, the electrochemical property of the tin-zinc composite oxides decreases.
Translated from Chem J Chin Univ, 2006, 27(12): 2252–2255 [译自: 高等学校化学学报] 相似文献
16.
Lingang Li Yu Tang Yuanming Zhang Jun Yang Biying Du 《Frontiers of Chemistry in China》2008,3(1):76-80
ZnS hollow nanospheres with holes were prepared by reacting ZnSO4 with H2S, the sulfide source formed in the reaction of CS2 with ethylenediamine, 1,3-propylenediamine, butylamine or 2-(2-aminoethylamino) ethanol, which also acted as a template agent,
at 50°C under agitation. The shape, particle size of about 100–850 nm and hole size of about 150–600 nm of ZnS hollow nanospheres
with holes were shown by SEM and TEM images. These ZnS nanospheres with β cubic ZnS phase and composed of 2–5 nm nanocrystals
were characterized by XRD and HRTEM. The blue shift of maximum absorption in UV-vis displayed the effect of quantum size.
The two amino groups of amine templates reacted favorably with Zn2+ to form uniform and relatively smooth ZnS nanospheres with holes, while hydroxyethyl played a disadvantageous role. A reasonable
mechanism of hole formation by H2S rushing out is suggested.
__________
Translated from Journal of Jinan University (Natural Science), 2007, 28(1): 92–95 [译自: 暨南大学学报(自然科学版)] 相似文献
17.
Yingpin Li Xiaoquan Zhou Huijing Zhou Zhurui Shen Tiehong Chen 《Frontiers of Chemistry in China》2008,3(2):128-132
Manganese dioxides with various morphologies were prepared using a common hydrothermalmethod without any templates or additives.
The evolution of the morphology was accompanied by the gradual conversion of the polymorphic forms from γ-type to β-type. Meanwhile, MnO2 microspheres, urchin-like nanostructures and nanowires were successfully synthesized. The products were characterized by
X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. The
evolution process can be explained by the Ostwald Ripening mechanism.
__________
Translated from Chinese Journal of Chinese Universities 28(7): 1223–1226 [译自: 高等学校化学学报] 相似文献
18.
TiO2 films were prepared by sol-gel method. In order to improve the utilization of light, the technologies of implantation of
transition metal ions (V+ and Cr+) and electron beam irradiation to deposit noble metal particles (Ag and Pt) were used. A red shift was found in the spectrum
of modified TiO2 films. The photocatalytic experiments showed that the photocatalytic ability under visible light irradiation could be improved
dramatically by both the implantation of transition metal and the electron beam irradiation.
__________
Translated from Chinese Journal of Catalysis, 2007, 28(1): 39–44 [译自: 催化学报] 相似文献
19.
The hydrophobic formation cationic starch (PSOAMDA) was prepared from starch (St), octadecyl acrylate (OA), acrylamide (AM)
and dimethyl diallyl ammonium chloride (DMDAAC) by means of inverse suspension polymerization with redox initiator. Water
with algae from Dianchi Lake was tested with PSOAMDA. Results show that when the molar ratio of St: AM: DMDAAC: OA is 4:8:1.5:0.6
and the reaction temperature is 40°C with a reaction time of 3 h, the monomer conversion yield, graft percentage and cationic
degree is 92.4%, 63.8% and 7.3%, respectively, and M
η = 3.26×106 g/vmol. It had been found from the flocculation of disposed water with algae from Dianchi Lake that the transparency and
COD elimination reach to 93.5% and 70.3%, respectively, with 15 mg/L PSOAMDA and at pH 6, vs. 91.3% and 69.2% obtained with
the commercial cationic polyacrylamide (PAM-C). When PSOAMDA dosage is 10–25 mg/L and the pH of aqueous solution is 6–10,
the flocculation performance is well capable of dealing with the water with algae from Dianchi Lake.
__________
Translated from Journal of Yunnan University (Natural Sciences Edition), 2007, 29(2): 177–182 [译自: 云南大学学报(自然科学版)] 相似文献
20.
Xiao Yang Youyuan Huang Henghui Zhou Jitao Chen Xinxiang Zhang 《Frontiers of Chemistry in China》2008,3(1):64-69
LiCo0.2Ni0.4Mn0.4O2, as the cathode material for lithium ion batteries, was modified by TiO2-coating. The effect of TiO2-coating on the structure and electrochemical performance of LiCo0.2Ni0.4Mn0.4O2 was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS),
and galvanostatic charge-discharge tests. The results suggest that a small amount of TiO2-coating does not change the crystalline structure, but considerably improves the electrochemical performance of LiCo0.2Ni0.4Mn0.4O2 in terms of capacity delivery and cyclability. XPS measurements confirm that the improved electrochemical performance is
most possibly attributed to a decrease in interaction between the layered material and non-aqueous electrolyte during the
charge-discharge processes.
__________
Translated from Chinese Journal of Inorganic Chemistry, 2007, 23(5): 753–758 [译自: 无机化学学报] 相似文献