[Precipitable Water Vapor Retrieval with MODIS Near Infrared Data].

Precipitable water vapor (PWV) shows great significance in remote sensing quantitative application and ecological research. Aiming at solving the problems of traditional methods, an Improved Continuum Interpolated Band Ratio (ICIBR) algorithm was proposed based on the ratios of apparent reflectance of multi-channels in this paper. The ICIBR algorithm considers the absorption characteristics of water vapor absorption in three MODIS near infrared channels (Bands 17, 18 and 19) and the relationship between the PWV and the ICIBRs of above three channels were simulated by using the MORTRAN model. Then the PWV retrieval model for MODIS data was constructed. Texas, Oklahoma region, a typical arid/semi-arid areas, located in North South America were selected as the study area and four different MODIS 1B data were obtained to perform PWV retrieval experiments using the ICIBR algorithm. Last, the corresponding GPS PWV ground observation data provided by SuomiNet and the MODIS PWV product (MOD05) were obtained to verify the experiment results. Evaluation and comparison results showed that the PWV retrievals showed a higher consistency (r=0.967) with the GPS ground measured PWV data with smaller RMSE~0.276 cm and a total of 71.08% of observation points falling within PWV Expected Errors (EE~±0.05+0.15PWVgps). Moreover, the ICIBR algorithm showed an obviously great improvement in PWV estimation, which can effectively reduce 61% overestimation of PWV retrievals than MOD05 PWV products. This new algorithm is more simple and practical with an overall more reliable retrieval accuracy.

Measurement-device-independent quantum key distribution over 200 km.

Measurement-device-independent quantum key distribution (MDIQKD) protocol is immune to all attacks on detection and guarantees the information-theoretical security even with imperfect single-photon detectors. Recently, several proof-of-principle demonstrations of MDIQKD have been achieved. Those experiments, although novel, are implemented through limited distance with a key rate less than 0.1 bit/s. Here, by developing a 75 MHz clock rate fully automatic and highly stable system and superconducting nanowire single-photon detectors with detection efficiencies of more than 40%, we extend the secure transmission distance of MDIQKD to 200 km and achieve a secure key rate 3 orders of magnitude higher. These results pave the way towards a quantum network with measurement-device-independent security.

Tenuibacillus halotolerans sp. nov., a novel bacterium isolated from a soil sample from a salt lake in Xinjiang, China and emended description of the genus Tenuibacillus.

A Gram-positive, moderately halotolerant, rod-shaped bacterium, designated YIM 94025(T), was isolated from a soil sample from a salt lake in Xinjiang province, north-west China. Strain YIM 94025(T) was observed to grow at 25-45 °C (optimum 37 °C), 0-22 % NaCl (optimum 2-10 %) and pH 6.0-9.0 (optimum pH 8.0). Phylogenetic analyses based on 16S rRNA gene sequences revealed that the organism belongs to the genus Tenuibacillus and exhibited sequence similarity of 98.0 % to the closest type strain, Tenuibacillus multivorans AS 1.3442(T). The predominant menaquinone was found to be MK-7; the cell-wall peptidoglycan diamino acid was meso-diaminopimelic acid; the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unidentified phospholipid and an unknown lipid; and the major fatty acids were found to contain iso-C(15:0), anteiso-C(15:0) and iso-C(16:0). The chemotaxonomic characteristics of strain YIM 94025(T) are consistent with those of the genus Tenuibacillus. The level of DNA-DNA relatedness value between YIM 94025(T) and T. multivorans AS 1.3442(T) was 36.6 ± 4.5 %. The G+C content of the strain YIM 94025(T) was determined to be 38.5 %. Based on the comparative analysis of physiological, biochemical and chemotaxonomic data, as well as DNA-DNA hybridization results, the isolate is considered to represent a novel species of the genus Tenuibacillus, for which the name Tenuibacillus halotolerans sp. nov., is proposed, with the type strain of YIM 94025(T) (=CCTCC AB 2012860(T) = KCTC 33046(T)).

Real-time energy measurement of high repetition rate ultrashort laser pulses using pulse integration and FPGA processing.

Real-time energy measurement using pulse integration method for high repetition rate ultrashort laser pulses based on FPGA (Field-Programmable Gate Array) and high-speed pipeline ADC (Analog-to-Digital Convertor) is introduced in this paper. There are two parts contained in this method: pulse integration and real-time data processing. The pulse integration circuit will convert the pulse to the step type signals which are linear to the laser pulse energy. Through the real-time data processing part, the amplitude of the step signals will be obtained by ADC sampling and conducting calculation in real time in FPGA. The test result shows that the method with good linearity (4.770%) and without pulse measurement missing is suitable for ultrashort laser pulses with high repetition rate up to 100 MHz.