Electrochemical impedance spectra (EIS) for lithium ion insertion and deinsertion in spinel LiMn 2 O 4 were obtained at different potentials and different temperatures during initial charge-discharge cycle. The results revealed that, at intermediate degrees of intercalation, three semicircles appeared in the Nyquist diagram. This new phenomenon has been investigated through EIS measurements as a function of temperature. It has found that the high frequency semicircle and the middle to high frequency semicircle begin to overlap each other above 20 °C, which indicates that the high frequency compressed semicircle commonly obtained at room temperature in the literature may consist of two semicircles. This signifies that the effects of the electronic and ionic transport properties of lithium intercalation materials clearly appear as separate features in the EIS spectra at low temperatures. A new equivalent circuit that includes elements related to the electronic and ionic transport, in addition to the charge transfer process, is proposed to simulate the experimental EIS data. The change of kinetic parameters for lithium ion insertion and deinsertion in spinel LiMn 2 O 4 as a function of potential in the first charge-discharge cycle is discussed in detail, and a modified model is proposed to explain the impedance response of the insertion materials for lithium ion batteries.

Due to advances in telemedicine, mobile medical care, wearable health monitoring, and electronic skin, great efforts have been directed to non-invasive monitoring and treatment of disease. These processes generally involve disease detection from interstitial fluid (ISF) instead of blood, and transdermal drug delivery. However, the quantitative extraction of ISF and the level of drug absorption are greatly affected by the individual’s skin permeability, which is closely related to the properties of the stratum corneum (SC). Therefore, measurement of SC impedance has been proposed as an appropriate way for assessing individual skin differences. In order to figure out the current status and research direction of human SC impedance detection, investigations regarding skin impedance measurement have been reviewed in this paper. Future directions are concluded after a review of impedance models, electrodes, measurement methods and systems, and their applications in treatment. It is believed that a well-matched skin impedance model and measurement method will be established for clinical and point-of care applications in the near future.

A double-laser beam lidar was successfully developed to simultaneously measure K and Na layers at Beijing (40.6°N, 116.2°E) in 2010. Statistical analysis of the parameters of sporadic K (K s ) and sporadic Na (Nas) layers was performed over 2 years of lidar data, and different characteristics of them were found. The average K s occurrence (2.9%) was lower than that of Nas (5.9%); the Nas occurrence had a maximum (19.3%) in May-June months and a minimum (1.6%) in January-February months, while the K s occurrence had a maximum (4.9%) in January-February months and a minimum (1.0%) in September-October months; most K s peaks tended to occur around 93 km, which was~2 km lower than that of Nas (~95 km); the K s peak density was often at least 1 order of magnitude lower than that of Nas; notably, two K s with high peak densities (>1000 cm À3 ) were observed, which were much higher than K density (15-300 cm À3 ) reported before. The ascending time of K s was often longer than its descending time, but an opposite trend occurred for Nas. During the 152 cases of joint observation for the K and Na layers, 21% (32/152) were cases in which K s and Nas events simultaneously occurred, while 79% (120/152) were cases in which only one layer (K or Na) exhibited a strong K s or Nas.

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The present results demonstrates that the main iridoid glycosides and crocetin derivatives in Gardenia can be obtained efficiently from extracts using HSCCC.

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