Electrochemical characteristics of amorphous silicon carbide film as a lithium-ion battery anode.

The electrochemical reactions of SiC film with Li+ have been investigated by electrochemical characterization and X-ray photoelectron spectroscopy. The SiC film is prepared by inductively-coupled-plasma chemical-vapor-deposition (ICP-CVD) technique and displays an amorphous state due to the low processing temperature (∼350 °C). An irreversible reaction of SiC with Li+ occurs with the formation of lithium silicon carbide (Li x Si y C) and elemental Si, followed by a reversible alloying/dealloying reaction of the elemental Si with Li+. The 500 nm SiC film shows an initial reversible specific capacity of 917 mA h g-1 with a capacity retention of 41.0% after 100 cycles at 0.3C charge/discharge current, and displays much better capacity retention than the Si film (5.2%). It is found that decreasing the SiC thickness effectively improves the specific capacity by enhancing the reaction kinetics but also degrades the capacity retention (for 250 nm SiC, its initial capacity is 1427 mA h g-1 with a capacity retention of 25.7% after 100 cycles). The better capacity retention of the 500 nm SiC anode is mainly because residual SiC exists in the film due to its incomplete reaction caused by its lower reaction kinetics, and it has high hardness and can act as a buffer matrix to alleviate the anode volume change, thus improving the mechanical stability and capacity retention of the SiC anode.

[Studies on chemical constituents from Buddleja lindleyana Fert].

OBJECTIVE: To study the chemical constituents of Buddleja lindleyana. METHOD: Separation by chromatographic methods and identification by spectral analysis. RESULT: Seven compounds vanillic acid, daidzein octacosanoic acid, beta-sitosterol-3-O-beta-D-glucopyranoside, stigmasterol-3-O-beta-D-glucopyranoside, alpha-spinasterol-3-O-beta-D-glucopyranoside, betulin acid were isolated. CONCLUSION: All the compounds were obtained from this plant for the first time.

Assessment of intradermal test in longitudinal surveillance of bancroftian filariasis.

Longitudinal surveillance was carried out consecutively during 1982-1987 in two pilot villages where bancroftian filariasis was prevalent in different severity before 1982. Intradermal test (IT) with filaria polypeptide (FPT) antigen prepared from Dirofilaria immitis was made. It was shown that the level of immediate hypersensitivity reaction to the antigen in population as shown by IT appeared to be directly proportional to both the prevalence of the disease and the infection rate of mosquitoes harbouring larval filariae before mass and selective treatment with diethylcarbamazine. Time for negative conversion of IT after chemotherapy was significantly longer in previous microfilaraemic patients than that in amicrofilaraemic cases. The selected three criteria of IT used in filariasis surveillance, namely, the positive rate, frequency of strong reaction and positive conversion rate, were diminished gradually after chemotherapy year by year, so that the three criteria were demonstrated to be useful for longitudinal surveillance of lymphatic filariasis.