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Additional file 1: Figure S1. The structure of the microfluidic chip. Figure S2. The BioDigital-QING dPCRTM system. Table S1. Training set sample information. Table S2. Sequence information for primers and probes. Table S3. Estimation of number of droplet required for a dPCR reaction.

Developing a convenient and rapid detection method for water is greatly desirable in the field of chemical industry. Herein, we present a simple and effective strategy combining a fluorescence sensor and a one-to-two fluorescence colorimetric logic operation to monitor water in a wide range of organic media and classify aprotic/protic polar solvents. The dual-emitting luminescent detector was prepared by incorporating a fluorescent dye Rhodamine 6G (R6G) with strong green light emission within a red light-emitting Eu-metal-organic framework (MOF) through the "bottle around ship" method. R6G@Eu-MOF displays completely different fluorescence response behaviors to various organic solvents. Thus, when one made use of the intensity ratio of different fluorescence emission centers, a 3D decoded map was proposed to reliably and effectively distinguish different aprotic/protic polar solvents. Moreover, R6G@Eu-MOF exhibited two different ratiometric sensing modes when detecting water in aprotic/protic polar solvents due to the hydrogen bonding interaction, that is ratiometry with one reference signal or two reversible signal changes. Furthermore, using water content as the input signal and two kinds of fluorescence emission as the output signals, a one-to-two logic gate system was constructed, making it possible to develop an intelligence system for water detection. Overall, we demonstrated for the first time that R6G@Eu-MOF could serve as an efficient platform for tracing water in organic media and distinguishing protic/aprotic polar organic solvents.

Agriculture is the foundation of the national economy. The periodicity of agricultural product output and prices, the asymmetry of information between buyers and sellers, and the inherent characteristics of small scale, high cost, and low profit have caused slow sales, which greatly hurt the enthusiasm of farmers to develop production and endanger social stability. Constructing an informationized and commercialized trading platform and an information sharing platform through e-commerce and establishing related systems and supervision mechanisms will help to promote the rapid growth of agricultural product sales. Research has shown that in the field of agricultural circulation, e-commerce has a significant effect on increasing the scale of agricultural trade.

In order to analyse the effects of inserts configurations on heat transfer performance of solar cavity receiver tube (RT), a three-dimensional numerical model with four different inserts under non-uniform heat flux boundary condition was developed. Based on this model, the effects of inserts configurations, the effects of non-uniform heat flux boundary condition, the effects of thickness and positions of twisted-tape were analyzed. The numerical results show that RT-I with the twisted-tapes has the better comprehensive performances than those of other three kinds of RTs, and the RT-I with twisted-tapes is recommended to the solar cavity tower receiver. The twisted-tape RT-I has the highest Nu and the lowest circumferential temperature difference ΔT and average temperature of outer surface of receiver tube Tm, which are 21.74, 43 K, and 586 K, respectively. In addition, the thickness of twisted-tape has the significant effect on heat transfer performances of RTs. The twisted-tape with much more thickness will enhance the heat transfer and reduce the ΔT and Tm. Moreover, under the non-uniform boundary heat fluxes, RT-I with twisted-tapes placed in the back-sunlight domain is favorable than that of twisted-tapes placed in the sunlight concentrated domain. The contribution can provide a reference for this type of receiver design and reconstruction.

Plateau zokors (Eospalax baileyi) are an agent actively involved in causing soil erosion and meadow degradation in the Yellow River Source Zone of West China. This study aims to quantify the amount of soil and nutrient loss from zokor mounds in relation to slope gradient and rainfall intensity, and to assess the amount of soil loss in zokor-infested areas compared with healthy meadows in Henan County, Qinghai Province. The results showed that zokor mounds were gradually lowered at a rate of 1.8&ndash, 3.9 cm h&minus, 1. Soil loss occurred two min after the rain began, reaching the maximum level during the first 20 min. The rate of soil loss and nutrient loss increased with the rainfall intensity and slope gradient. When the rainfall intensity rose from 5 to 10 mm h&minus, 1, and from 10 to 15 mm h&minus, 1, the total soil loss on 10&deg, slopes increased by 2.5 times and 3.9 times, respectively, and soil nutrient loss increased by 1.7 times and 2.7 times, respectively. As the slope gradient steepened to 20&deg, the corresponding figures were 2.8 times and 4.3 times for total soil loss, and 1.8 times and 2.9 times, respectively, for soil nutrient loss. When the slope rose to 30&deg, the soil loss increased by 3.0 and 4.5 times, and the soil nutrient loss increased by 1.8 times and 3.1 times, respectively. There was a power function between soil loss and surface runoff (S = 0.2371Q2.2307, R2 = 0.9529). The soil was eroded at a rate of 256.6 g m&minus, 2 h&minus, 1 from zokor mounds, 17.7 times higher than in intact meadows, and 1.8 times higher than in partially recovered meadows. Most of the eroded soils had a mean diameter of 0&ndash, 1.2 mm. It is recommended that artificial control of plateau zokors should be implemented, together with other ecological restoration measures to restrain the soil erosion problem caused by zokor activities.

In this work, a novel and effective ratio fluorescent porphyrin metal–organic framework (MOF) probe by encapsulating UiO-66(OH)2 into the porphyrin MOF (PCN-224) was prepared, showing the excellent fluorescence performance in detecting Cu2+. In this probe, the signal from the green-emission UiO-66(OH)2 encapsulated in PCN-224 was deemed as an effective reference, thus affording an effective built-in correction in complex environmental effects. The red-emission PCN-224 contained the active site for detecting Cu2+. At the same time, Cu2+ can selectively quench the fluorescence intensity of PCN-224. The ratiometric probe therefore gave an effective and reliable Cu2+ determination platform with an LOD value as low as 0.068 nM. This LOD result was better than the Cu2+ concentration limitation in drinking water regulated by World Health Organization (WHO) and reported by some other methods. This provides a simple new sensor for rapidly detecting copper ions, which can be further expanded in various environmenta...