LiFePO4 doped with magnesium prepared by hydrothermal reaction in glucose solution

Lithium iron phosphate （LiFePO4） doped with magnesium was hydrothermally synthesized from commercial LiOH, FeSO4, H3PO4 and MgSO4 with glucose as carbon precursor in aqueous solution. The samples were characterized by X-ray powder diffraction, scanning electron microscopy and constant charge-discharge cycling. The results show that the synthesized powders have been in situ coated with carbon precursor produced from caramel reaction of glucose. At ambient temperature （28±2℃）, the electrochemical performances of LiFePO4 prepared exhibit the high discharge capacity of 135 mAh g^-1 at 5C and good capacity retention of 98% over 90 cycles. The excellent electrochemical performances should be correlated with the intimate contact between carbon and LiFePO4 primary and secondary particles, resulting from the in situ formation of carbon precursor/carbon, leading to the increase in conductivity of LiFePO4.     

NOVEL pH-SENSITIVE DRUG DELIVERY SYSTEM BASED ON NATURAL POLYSACCHARIDE FOR DOXORUBICIN RELEASE

A novel pH-sensitive nanoparticle drug delivery system (DDS) derived fl'om natural polysaccharide pullulan for doxorubicin (DOX) release was prepared.Pullulan was functionalized by successive carboxymethylization and amidation to introduce hydrazide groups.DOX was then grafted onto pullulan backbone through the pH-sensitive hydrazone bond to form a pullulan/DOX conjugate.This conjugate self-assembled to form nano-sized particles in aqueous solution as a result of the hydrophobic interaction of the DOX.Tr...     

Reversible redox-switchable second-order optical nonlinearity in polyoxometalate: a quantum chemical study of [PW11O39(ReN)]n- (n = 3-7)

In this paper, the relationship between the reversible redox properties and the second-order nonlinear optical (NLO) responses for the title series of complexes has been systematically investigated by using the time-dependent density functional theory (TDDFT) method combined with the sum-over-states (SOS) formalism. The results reveal that the successive reduction processes of five PW11ReN redox states should be PW11ReVII (1) --> PW11ReVI (2) --> PW11ReV (3) --> PW11ReV1e ( 4) --> PW 11ReV2e (5). Furthermore, their electrochemical properties have been reproduced successfully. It is noteworthy that the second-order NLO behaviors can be switched by reversible redox for the present studied complexes. Full oxidation constitutes a convenient way to switch off the second-order polarizability (system 1). The incorporation of extra electrons causes significant enhancement in the second-order NLO activity, especially for the third reduced state (system 4), whose static second-order polarizability (betavec) is about 144 times larger than that of fully oxidized 1. The characteristic of the charge-transfer transition corresponding to the dominant contributions to the betavec values indicates that metal-centered redox processes influence the intramolecular donor or acceptor character. Therefore, these kinds of complexes with the facile and reversible redox states could become excellent switchable NLO materials.     

C60 on SiC nanomesh

A SiC nanomesh is used as a nanotemplate to direct the epitaxy of C60 molecules. The epitaxial growth of C60 molecules on SiC nanomesh at room temperature is investigated by in situ scanning tunneling microscopy, revealing a typical Stranski-Krastanov mode (i.e., for the first one or two monolayers, it is a layer-by-layer growth or 2-D nucleation mode; at higher thicknesses, it changes to island growth or a 3-D nucleation mode). At submonolayer (0.04 and 0.2 ML) coverage, C60 molecules tend to aggregate to form single-layer C60 islands that mainly decorate terrace edges, leaving the uncovered SiC nanomesh almost free of C60 molecules. At 1 ML C60 coverage, a complete wetting layer of hexagonally close-packed C60 molecules forms on top of the SiC nanomesh. At higher coverage from 4.5 ML onward, the C60 stacking adopts a (111) oriented face-centered-cubic (fcc) structure. Strong bright and dim molecular contrasts have been observed on the first layer of C60 molecules, which are proposed to originate from electronic effects in a single-layer C60 island or the different coupling of C60 molecules to SiC nanomesh. These STM molecular contrast patterns completely disappear on the second and all the subsequent C60 layers. It is also found that the nanomesh can be fully recovered by annealing the C60/SiC nanomesh sample at 200 degrees C for 20 min.     

Diethylenetriamine-grafted poly(glycidyl methacrylate) adsorbent for effective copper ion adsorption

Amine-functionalized adsorbents have attracted increasing interest in recent years for heavy metal removal. In this study, diethylenetriamine (DETA) was successfully grafted (through a relatively simple solution reaction) onto poly(glycidyl methacrylate) (PGMA) microgranules to obtain an adsorbent (PGMA-DETA) with a very high content of amine groups and the PGMA-DETA adsorbent was examined for copper ion removal in a series of batch adsorption experiments. It was found that the PGMA-DETA adsorbent achieved excellent adsorption performance in copper ion removal and the adsorption was most effective at pH>3 in the pH range of 1-5 examined. X-ray photoelectron spectroscopy (XPS) revealed that there were different types of amine sites on the surfaces of the PGMA-DETA adsorbent but copper ion adsorption was mainly through forming surface complexes with the neutral amine groups on the adsorbent, resulting in better adsorption performance at a higher solution pH value. The adsorption isotherm data best obeyed the Langmuir-Freundlich model and the adsorption capacity reached 1.5 mmol/g in the case of pH 5 studied. The adsorption process was fast (with adsorption equilibrium time less than 1-4 h) and closely followed the pseudo-second-order kinetic model. Desorption of copper ions from the PGMA-DETA adsorbent was most effectively achieved in a 0.1 M dilute nitric acid solution, with 80% of the desorption being completed within the first 1 min. Consecutive adsorption-desorption experiments showed that the PGMA-DETA adsorbent can be reused almost without any loss in the adsorption capacity.     

Novel Water‐Soluble Shape‐Regulatable Luminescent Nanoparticles by Non‐Covalently Bonded Self‐Assembly

Summary: Novel non‐covalently connected water‐soluble nanoparticles that contain poly(fluorene‐co‐phenylene) with hydroxy‐capped alkoxy side chains (PF3BOH) and poly(acrylic acid) (PAA) have been obtained and characterized. With different proportions of PF3BOH and PAA, the shape and size of the nanoparticles can be regulated. The nanoparticles are quite stable in water with no precipitate being observed after weeks. Transmission electron microscopy and dynamic laser light scattering are used to confirm the morphology of the PF3BOH/PAA nanoparticles. Their optical properties have been investigated and show similar optoelectronic properties to a PF3BOH solid film although they do not undergo aggregation.

TEM images of the nanoparticles obtained upon varying the PAA/PF3BOH content.     

A Home-made Simple Set-up for Measurement of Electrochemical Surface Tension Spectrum on a Mercury Drop Electrode

A setup for recording surface tension curves at a mercury drop during potential scanning is designed based on photo-sensitive detection system. Surface tension spectrum at Hg drop can be recorded by voltammetric study. A Yb(III)-NO2- catalytic reduction system was used for characterization. The simple, sensitive technique can be expected to provide fresh information on molecular interactions at electrode surfaces.     

新型纤维素衍生物手性固定相的制备及其对几种对映异构体的高效液相色谱分离

合成了一种经环十二烷修饰的纤维素酯，将其涂敷于小粒径的氨丙基化硅胶（APS）上，制备出高效液相色谱手性固定相，以正己烷、异丙醇为流动相拆分了2-对氯苯基丙腈、1-对氟苯基乙醇、1-对叔丁基苯氧基-2-丙醇、2-对氯苯基辛腈及三唑醇等5种外消旋对映体，并考察了流动相中异丙醇含量对分离效果的影响。     

A simple and direct isolation of whey components from raw milk by gel filtration chromatography and structural characterization by Fourier transform Raman spectroscopy

A simple and economical method to isolate whey protein from fresh raw milk is developed by serial defatting, casein eliminating, lactose removing, and separating by gel filtration chromatography. Four major whey components, including immunoglobulin (Ig), bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and -lactalbumin (-Lac), and a non-protein of low molecular mass (1.7 kDa) but strong absorbance at 280 nm, are detected simultaneously. The small non-protein molecule is rich in aromatic amino acids and thiol groups as supported by the structural characterization with near infrared Fourier transform Raman spectroscopy (FT-Raman). FT-Raman results show that the secondary structure of Ig is dominated by anti-parallel β-pleated sheet; BSA is mainly in -helix; both β-form and unordered structure are important in β-Lg; while -Lac is mostly in -helix coupling with random coil. Differences in the Raman profile for each whey component reflect their intrinsic compositional differences and distinct spatial arrangement. The S–S linkages diverging around 510–540 cm⁻¹ indicate that the conformation of disulfide bonds in each whey components is different, which may be responsible for their diversified behaviors in solubility, rheological and functional properties.