The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The ...The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The liquid crystal structure and behavior have been alsostudied by using polarizing texture, small angle X-ray scattering, ~2H-NMR and rheometer etc. Theresult shows that when the composition of the system changes along the line of AA′ in this largeliquid crystal region, the structural change iscubic→cubic/lamellar→lamellar→larnellar/hexagonal→hexagonal. Meanwhile, we made the firstattempt of systematic study of the rheological properties of the above system. The lattice constantsof cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.展开更多
Mn doping is deemed as a promising strategy to improve the electrochemical performance of the a-Ni(OH)_(2)battery-type supercapacitor electrode.However,the internal structure evolution,the pathways and the dynamics of...Mn doping is deemed as a promising strategy to improve the electrochemical performance of the a-Ni(OH)_(2)battery-type supercapacitor electrode.However,the internal structure evolution,the pathways and the dynamics of the proton/intercalated anion migration,as well as the functioning mechanism of Mn dopant to stabilize the layered structure during cycles remain unclear.Here,we unveil that irreversible oxidization of Mn^(3+)at the initial CV cycles,which will remain as Mn^(4+)in the NiO_(2)slabs after the first oxidization to effectively suppress the phase transformation fromα-Ni(OH)_(2)/γ-NiOOH toβ-Ni(OH)_(2)/β-NiOOH and further maintain the structural integrity of electrode.With a synergistic combination of theoretical calculations and various structural probes including XRD and^(2)H MAS solid state NMR,we decode the structure evolution and dynamics in the initial CV(cyclic voltammetry)cycles,including the absorption/desorption of hydrogen containing species,migration of intercalated anions/water molecules and the change of interlayer space.This present work elucidates a close relationship between doping chemistry and structural reliability,paving a novel way of reengineering supercapacitor electrode materials.展开更多
Oriented stratum corneum model lipid membranes were used to study the influence of the short chain ceramides （CER）[NP] and [AP] as well as the impact of the lipophilic penetration enhancer molecules oleic acid （O...Oriented stratum corneum model lipid membranes were used to study the influence of the short chain ceramides （CER）[NP] and [AP] as well as the impact of the lipophilic penetration enhancer molecules oleic acid （OA） and isopropyl myristate （IPM） on the lipid nanostrueture. The influence of the enhancer molecules were studied using specifically deuterated OA and IPM and neutron diffraction. 2H NMR spectroscopy was used to study the impact of the ceramides＇ degree of order within the stratum corneum model lipid membranes. It was found that CER[NP] forms two very stable phases with high resistance against temperature increase. Phase B showed unusual hydration behavior as no water uptake of this phase was observed. The 2H NMR spectroscopic measurements showed that CER[NP] based ternary model system had a higher state of lamellar order in comparison to CER[AP] based lipid matrix. The studies confirmed that the short chain ceramides, particularly CER[NP], have a very high impact on the integrity of the Stratum comeum lipid bilayers. The penetration enhancer OA has not influenced the repeat distance of the model membrane based on CER[AP], and was not able to induce a phase separation in the investigated lipid matrix. However, a disorder and a fluidisation of the model membranes were observed when OA was incorporated. IPM showed the same effect but two phases （assigned as phase A and B） appeared, when IPM was used as penetration enhancer and incorporated into the model membrane. Furthermore, two arrangements of IPM were identified in phase A using deuterated IPM. A model of the nanostructure of the Stratum corneum lipid membranes is presented.展开更多
Splendidly colored lyotropic liquid crystals formed in the ternary system of a novel cationic surfactant, 3-p-nonylphenoxy-2-hydroxypropyl trimethyl ammonium bromide (NPTAB)-n-butanol-water system, had been ob-served ...Splendidly colored lyotropic liquid crystals formed in the ternary system of a novel cationic surfactant, 3-p-nonylphenoxy-2-hydroxypropyl trimethyl ammonium bromide (NPTAB)-n-butanol-water system, had been ob-served under polarized light microscope. Small-angle X-ray scattering (SAXS), 2H (deuterium) quadrupolar splitting (2H NMR) were employed to confirm the structures of these liq-uid crystals. The structural transformation of these special lyotropic liquid crystals had been confirmed by differential scanning calorimetry (DSC). The influences of liquid crystal film thickness, temperature and conserving time on the color of liquid crystals have been investigated. It is also theoreti-cally discussed for forming and changing of liquid crystal color.展开更多
Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobala...Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV-vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 30370945) Guizhou Provincial Governor Foundation (No. 6, 2001).
文摘The pseudo-quaternary phase diagram of Brij35/sodium oleate/oleic acid/watersystems has been investigated, and the liquid crystal area has been identified, which covers abouttwo thirds of the whole phase diagram. The liquid crystal structure and behavior have been alsostudied by using polarizing texture, small angle X-ray scattering, ~2H-NMR and rheometer etc. Theresult shows that when the composition of the system changes along the line of AA′ in this largeliquid crystal region, the structural change iscubic→cubic/lamellar→lamellar→larnellar/hexagonal→hexagonal. Meanwhile, we made the firstattempt of systematic study of the rheological properties of the above system. The lattice constantsof cubic and hexagonal liquid crystals are 10.53 and 5.68 nm, respectively.
基金supported by the National Natural Science Foundation of China(Grant No.21673065,No.21403045,No.21611130177)。
文摘Mn doping is deemed as a promising strategy to improve the electrochemical performance of the a-Ni(OH)_(2)battery-type supercapacitor electrode.However,the internal structure evolution,the pathways and the dynamics of the proton/intercalated anion migration,as well as the functioning mechanism of Mn dopant to stabilize the layered structure during cycles remain unclear.Here,we unveil that irreversible oxidization of Mn^(3+)at the initial CV cycles,which will remain as Mn^(4+)in the NiO_(2)slabs after the first oxidization to effectively suppress the phase transformation fromα-Ni(OH)_(2)/γ-NiOOH toβ-Ni(OH)_(2)/β-NiOOH and further maintain the structural integrity of electrode.With a synergistic combination of theoretical calculations and various structural probes including XRD and^(2)H MAS solid state NMR,we decode the structure evolution and dynamics in the initial CV(cyclic voltammetry)cycles,including the absorption/desorption of hydrogen containing species,migration of intercalated anions/water molecules and the change of interlayer space.This present work elucidates a close relationship between doping chemistry and structural reliability,paving a novel way of reengineering supercapacitor electrode materials.
文摘Oriented stratum corneum model lipid membranes were used to study the influence of the short chain ceramides （CER）[NP] and [AP] as well as the impact of the lipophilic penetration enhancer molecules oleic acid （OA） and isopropyl myristate （IPM） on the lipid nanostrueture. The influence of the enhancer molecules were studied using specifically deuterated OA and IPM and neutron diffraction. 2H NMR spectroscopy was used to study the impact of the ceramides＇ degree of order within the stratum corneum model lipid membranes. It was found that CER[NP] forms two very stable phases with high resistance against temperature increase. Phase B showed unusual hydration behavior as no water uptake of this phase was observed. The 2H NMR spectroscopic measurements showed that CER[NP] based ternary model system had a higher state of lamellar order in comparison to CER[AP] based lipid matrix. The studies confirmed that the short chain ceramides, particularly CER[NP], have a very high impact on the integrity of the Stratum comeum lipid bilayers. The penetration enhancer OA has not influenced the repeat distance of the model membrane based on CER[AP], and was not able to induce a phase separation in the investigated lipid matrix. However, a disorder and a fluidisation of the model membranes were observed when OA was incorporated. IPM showed the same effect but two phases （assigned as phase A and B） appeared, when IPM was used as penetration enhancer and incorporated into the model membrane. Furthermore, two arrangements of IPM were identified in phase A using deuterated IPM. A model of the nanostructure of the Stratum corneum lipid membranes is presented.
基金This work was supported by the National Natural Science Foundation of China(Grant No.30370945)the Science Research Developed Foundation of Liaocheng University.
文摘Splendidly colored lyotropic liquid crystals formed in the ternary system of a novel cationic surfactant, 3-p-nonylphenoxy-2-hydroxypropyl trimethyl ammonium bromide (NPTAB)-n-butanol-water system, had been ob-served under polarized light microscope. Small-angle X-ray scattering (SAXS), 2H (deuterium) quadrupolar splitting (2H NMR) were employed to confirm the structures of these liq-uid crystals. The structural transformation of these special lyotropic liquid crystals had been confirmed by differential scanning calorimetry (DSC). The influences of liquid crystal film thickness, temperature and conserving time on the color of liquid crystals have been investigated. It is also theoreti-cally discussed for forming and changing of liquid crystal color.
基金Project supported by the National Natural Science Foundation of China.
文摘Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV-vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.
