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Accurate gold determination in geological samples is important for studying geological problems. Here we perform a comparative study on four desorption methods based on meta-analysis and propose a new desorption method of polyurethane foam for gold determination.

Condensed π-conjugation C-PAN/MS-CN nanotubes were obtained through the facile polyacrylonitrile (PAN)-confined molten salt (MS) thermal condensation of melamine.

48 surface soil samples from the main urban areas in Changchun, Northeast China were analyzed for 18 organochlorine pesticides (OCPs) with the aim of elucidating their contamination status, distribution characteristics, influencing factors, and potential risks in this urban region. The total concentrations of OCPs ranged from 15.63 to 92.79 ng/g, with the geomean of 36.46ng/g. HCHs, DDTs, and Chlordanes were the most dominant OCPs, with γ-HCH and p,p'-DDT being the predominant isomer. Higher concentrations of OCPs mainly concentrated in the northeast and southwest of Changchun city and the artificial influences contributed to the fate of OCPs in the soils. The residues of OCPs were mainly derived from the historical application of the technology DDT, dicofol, and lindane. Pearson’s correlation analysis indicated that TOC was a key factor controlling OCPs accumulation. The data analysis based on the soil quality guidelines (SQGs) suggested that the presence of DDTs, lindane, and heptachlor may pose a certainly toxic ecological threat to the soil organisms. The evaluation results of incremental lifetime cancer risk (ILCR) showed that the cancer risk of OCPs to the posed population was low, while some specific locations with high OCPs residues ought to be a cause for concern.

Supramolecular host molecules are used as tools in the design of multifunctional nanoparticles for sensors, catalysts, biometric elements, etc. Combining with carbon dots (CDs) has excellent host-guest recognition properties and fluorescence characteristics, which can precisely capture and identify target analytes. Consequently, supramolecular host molecules-based CDs can significantly improve the detection performance of ions and molecules with different structures or intrinsic chemical properties. This currently responds to a wide range of analytes including metal cations, anions, organic compounds and other biomolecules, yielding fascinating achievements in the field of chemistry. Therefore, the present review summarizes outstanding supramolecular host molecules-based CDs reported in the past ten years. The focus is on elucidating the mechanisms, methodologies, advantages and disadvantages of modifying or preparing CDs with supramolecular host molecules. Current challenges encountered and outlooks are also be discussed.

Rock weathering is the main source of element geochemical cycle, which has a very important impact on the environment. Three well-developed basalt weathering profiles in Changbai Mountain area are selected in this study, and the samples of parent rock, parent material layer, sedimentary layer, and leaching layer are systematically collected. The systematic study showed that the basalt in the study area experienced moderate chemical weathering under warm and humid climate conditions, with leaching of some major elements such as silicon and aluminum. The distribution of the rare earth elements (REE) in the weathering products recalls that of an alkali-basalt, with an evident fractionation between light- and heavy-REE. Such a feature is therefore referable to the parent volcanic rock, although with some degree of leaching.

The source of recombinant collagen is clean, and it has the advantages of flexible sequence design, high yield and high purity, so it has a wide application prospect as biomaterials in tissue engineering and other fields. However, how to promote the cross-linking of recombinant collagen molecules and make them form a more stable spatial structure is the difficulty to be overcome in the design of recombinant collagen nanomaterials. Unnatural amino acid O-(2-bromoethyl)-tyrosine was incorporated into collagen by two-plasmid expression system. The results showed that high-purity collagen incorporated with unnatural amino acid could be obtained by induction with final concentration of 0.5 mmol/L IPTG and 0.06% arabinose at 25 °C for 24 hours. The intermolecular cross-linking through thioether bond was formed between collagen molecule incorporated with unnatural amino acid and collagen molecule with cysteine mutation in pH 9.0 NH4HCO3 buffer, which formed aggregates with the largest molecular size up to 1 micrometre. The results pave the way for the design of recombinant collagen biomaterials.

Reducing CO2 emissions is critical to sustainable economic development in China. In this article, we try to assess the implementation of dual controls policy on CO2 emissions within a unifi...

Taking renewable energy consumption as a concomitant variable and using data from 25 manufacturing subsectors in 38 countries from 2000 to 2014, this paper investigates the impact of economic growth on CO2 emissions at the subsector level by employing an endogenous finite mixture model for the first time. The results are as follows: (1) Manufacturing growth has led to a significant increase of CO2 emissions, but this promoting effect becomes weak as the share of renewable energy consumption expands; (2) With the growing impact of renewable energy consumption, nearly half of the sample countries and two-thirds of the subsectors have experienced the transformation of the nexus between manufacturing growth and emissions; and (3) Compared with coal, coke and crude, the growth of the manufacturing subsector that is mainly dependent on natural gas, electricity and heat, has produced lower emissions. Our findings provide significant evidence of and references for formulating renewable energy policy for various manufacturing subsectors.

Adaptive evolution is an effective strategy to obtain industrial strains with excellent performance, but this method is time-consuming and less efficient. To solve these problems, we constructed an autonomous evolution mutation system (AEMS) to promote the occurrence of mutations, based on the hierarchical dynamic control between the high-fidelity module and the mutagenic module. AEMS was applied in Bacillus subtilis to screen acetoin tolerance phenotypes and high-producing strains. The minimal inhibitory concentration of acetoin exhibited a large increase from 40 to 60 g/L, and acetoin production was increased by 42.8% compared to that of B. subtilis 168. Scaled-up production of acetoin with the directed evolution strain B. subtilis HS019 in a 30-L fermentor resulted in acetoin titer up to 82.5 g/L. These results indicated that AEMS could improve the efficiency of evolution and provide an effective method for obtaining tolerance phenotypes and high-producing strains.

By means of electrochemical atomic layer deposition (ECALD), cobalt selenide counter electrodes have been successfully prepared on FTO substrate for the first time. The as-grown films presented amorphous structure and their composition and microstructure could be regulated effectively by adjusting the depositing potential of Se via the route of ECALD. Cycle voltammograms and Tafel polarization measurements revealed that the cobalt selenide counter electrode exhibited an excellent catalytic activity and stability in the I−/I3− system. Due to the more active catalytic sites and less charge-transfer resistance, the Co1.2Se counter electrode yielded faster and more complete reduction of I3− to I− than the Pt and other compositions of cobalt selenide. As a result, the dye-sensitized solar cell based on the Co1.2Se counter electrode yielded a photoconversion efficiency of 9.28%, which improved by 136% than that of the DSSC based on the Pt electrode (6.84%). Taking the facility and cost efficiency into consideration, ECALD has great potential in preparing high efficient counter electrode for high performance DSSCs.

By dipping the mesoporous TiO 2 film in Sr 2+ solutions and subsequent annealing, a modification layer of SrTiO 3 has been formed on the surface of the mesoporous TiO 2 film, and the effect of modification on the photovoltaic characteristics of the perovskite solar cells has been studied detailedly. The XPS and TEM results verified the existence and nature of the SrTiO 3 modification layer. Benifiting from the TiO 2 surface modification, the morphology of perovskite film and light absorption of the CH 3 NH 3 PbI 3 absorber have been improved effectively, and a faster charge transfer has also been achieved between the CH 3 NH 3 PbI 3 perovskite layer and the modified TiO 2 . As a result, an average conversion efficiency of 11.4% has been achieved in the perovskite solar cell based on the modified mesoporous TiO 2 by 10 mM Sr 2+ solution, and it increases approximately by 46% in comparison with the photovoltaic efficiency of 7.8% of the perovskite solar cell based the bare mesoporous TiO 2 layer.

In this paper, a hybrid generator has been fabricated by connecting a dye sensitized solar cell (DSSC) with a single p–n junction thermoelectric generator (TEG) in series. Both the open-circuit voltage and the short circuit current of the hybrid generator have been enhanced obviously in comparison with the algebraic sum of those of the DSSC and TEG. The increase of non-equilibrium carrier concentration originates from the synergistic effect between the TEG and DSSC, which lifts the quasi-Fermi energy level and improve the photoelectric response rate thus enhancing the open-circuit voltage and current density of the DSSC. As a result, a conversion efficiency of 9.08% has been obtained in hybrid B, which is greatly enhanced by 20.6% and 725.5% in comparison with that of the separate DSSC and TEG, respectively.

In this study, high coverage and uniformly distributed Bi 2 S 3 and Sb 2 S 3 quantum dots (QDs) are deposited simultaneously on the surface of TiO 2 nanorods (NRs) via electrochemical atomic layer deposition (ECALD) method. The structure, morphology and composition of the deposits are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersion spectroscopy analysis (EDS), respectively. The results show that the deposits are of Bi 2 S 3 and Sb 2 S 3 compound semiconductor, and the Bi 2 S 3 /Sb 2 S 3 QDs cover on the top and side surface of TiO 2 NRs homogeneously. EDS analysis demonstrates that the ratio of both S to Sb and S to Bi are approximately 3:2, indicating that ECALD method can well control the deposition of each element. Owing to the better light absorption property and reduced recombination possibility of Bi 2 S 3 /Sb 2 S 3 QDs co-sensitized solar cells, the power conversion efficiency reaches 0.67% with a short-circuit current density of 4.83 mA cm −2 at AM 1.5 solar light of 100 mW cm −2 , which is much higher than that of Bi 2 S 3 or Sb 2 S 3 QDs sensitized solar cells.

Hexachlorocyclohexane(HCH) and Dichlorodiphenyltrichloroethane (DDT) are typical Organochlorine pesticides (OCPs), which were widely used in pest control and insect infestation in China. This study aimed at researching the concentration, potential sources and potential risk of HCH and DDT in Jilin University in Changchun, China. A total of 45 surface soil samples were collected from five land-use types in Jilin University campuses, the contents of were determined by Gas Chromatography and Mass Spectrometry (GC-MS) with Soxhlet extraction pretreatment technology. The overall HCHs existed the pollution in some campuses, while the DDTs were relatively low without pollution. Results of composition analysis showed that HCHs in campus soils mainly came from the mixed use of technical HCHs and lindane, and DDTs were mainly from the input of historical dicofol products. The potential health risks of HCHs and DDTs to campus populations were very low, while the potential ecological risks of HCHs and DDTs individual isomers should be paid attentions to.

In order to effectively curb the rapidly-increasing energy consumption in manufacturing industry, China has clearly stated in Made in China 2025, to reduce energy consumption per unit of industrial added value of the manufacturing by 18% in 2020 and 34% in 2025 relative to the 2015 level. Based on the ZSG-DEA and CAT models, this paper attempts to establish an efficiency-oriented energy-consuming right trading system (ECRTS) to design the energy allocation scheme along with the energy trading scheme for China’s 18 manufacturing sectors in 2020 and 2025. We find sectors with the allocated energy-consuming right could not only reach the DEA efficiency frontier, but also upgrade their energy-consuming mix. Further, the allocation scheme considering the sectoral heterogeneity is more rational as it relieves the pressure on some sectors to conserve energy. Finally, by integrating energy offsetting mechanism into the united energy market, the energy trading mechanism designed in this work can largely simplify the transaction process and improve the after-trading efficiency for all target sectors.

This paper applies the zero-sum gains data envelopment analysis (ZSG-DEA) model to assess the provincial CO2 emission reduction scheme of China in 2020 and then calculates optimized values for the provinces in 2030. Results from two standard optimization procedures to solve the ZSG-DEA model are compared. We also extend the current methods by improving the iterative approach and then introduce fairness to the efficiency-oriented approach for the 2030 case. We found that the choice of optimization procedures has only a minimal impact on the results, but the specification of model does matter. For 2020, a standard DEA approach shows that only 2 provinces out of 30 are efficient. According to the estimation results of the ZSG-DEA model, 12 provinces need to set higher reduction targets, whereas the other 18 provinces could have lower target values to achieve overall efficiency. These results are generally consistent across different optimization approaches. The improved approach is applied to further evaluate a number of scenarios in 2030, in which the adjustment values towards optimum can be calculated for each scenario. Furthermore, we show that the inclusion of fairness can significantly affect the adjustment targets, which is of great importance to policymakers

A novel bi-layer structure assembled by nanorods and three-dimensional hierarchical TiO 2 is synthesized by a facile two step hydrothermal method. By adjusting the acid concentration, the morphology of three-dimensional hierarchical TiO 2 can be well controlled. This bi-layer structure combines the merits of one-dimensional nanorods which can serve as direct electrons transport pathways and three-dimensional hierarchical structure supplying light scattering ability and large specific surface area for dye loading. Hence, the photovoltaic performance of the dye-sensitized solar cells based on the bi-layer TiO 2 is greatly enhanced compared to that of single nanorods film. The maximum short-circuit current and power conversion efficiency of the DSSCs based on bi-layer TiO 2 structure reach 12.55 mA/cm 2 and 5.61% respectively, which are remarkably larger than those of 5.00 mA/cm 2 and 2.38% for the DSSC based on a single layer TiO 2 nanorods film. The superior performance of bi-layer TiO 2 structure is attributed to the large dye loading amount and light scattering properties due to the unique hierarchical structure.