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In this paper, sunflower seed husks were used as raw materials to prepare porous biomass carbon through physical carbonization and chemical activation. Calcium chloride and pyromellitic acid were used as activators and processing assistant. The influences of activation temperature and processing additives on the activation mechanism of CaCl2 were analyzed. The results showed that activation temperature and processing aids act on the two competing mechanisms of micropore formation and pore expansion, respectively. The average pore diameter of the resulting sample was 9.75 nm, and the specific surface area was 404.215 m2 g−1. The sample was circulated 100 cycles at 0.2 C. The specific flow was 1100 mAh g−1 in the change rate test. The discharge specific capacity was 590 mAh g−1 after 450 cycles at 2 C rate. The structure of the sample collapsed after 250 cycles at 5 C, and the specific discharge capacity dropped to 390 mAh g−1 after 350 cycles.

The cryogenic process has been widely applied in various fields, but it has rarely been reported in the preparation of anode materials for lithium-ion battery. In this paper, activated carbon derived from hemp stems was prepared by carbonization and activation; then, it was subjected to cryogenic treatment to obtain cryogenic activated carbon. The characterization results show that the cryogenic activated carbon (CAC) has a richer pore structure than the activated carbon (AC) without cryogenic treatment, and its specific surface area is 1727.96 m2/g. The porous carbon had an excellent reversible capacity of 756.8 mAh/g after 100 cycles at 0.2 C as anode of lithium-ion battery, in which the electrochemical performance of CAC was remarkably improved due to its good pore structure. This provides a new idea for the preparation of anode materials for high-capacity lithium-ion batteries.

TiO2 precursor has been synthesized by sol-solvothermal method with tetrabutyl titanate as raw material. Nitrogen-modified TiO2 with different reaction temperatures (150, 180, 200 °C) was successfu...

ZnO is considered to be the next generation lithium-ion battery anode material due to its high theoretical capacity, low potential, abundant resources and low toxicity. However, high volume expansion during charge–discharge process makes ZnO powdered and agglomerated easily. In the work, we fabricate a porous carbon skeleton by using rice husk (RH) lignin, and the ZnO nanoparticles are supported on the skeleton uniformly. Its unique structure provides excellent stability and electrical conductivity. RH as a carbon source will improve the utilization rate of biomass materials in the refining process. The samples were characterised by XRD, Raman, TG, SEM and transmission electron microscopy, and the materials presented a promising Li storage properties and electrochemical performance with a discharge capacity of 898.1 mAh g−1 at 0.2C after 110 cycles, which is very close to the theoretical specific capacity of zinc oxide (978 mAh g−1).

We employ the coarse-grained molecular dynamics simulation to investigate the fundamental structural and dynamic properties of the ionic solution with and without the application of an external electric field. Our simulations, in which the solvent molecules are treated as Stockmayer fluids and the ions are modeled as spheres, can effectively account for the multi-body correlations between ion-ion, ion-dipole, and dipole-dipole interactions, which are often ignored by the mean-field theories or coarse-grained simulations based on a dielectric continuum. By focusing on the coupling between effects of ion solvation, electrostatic correlations and applied electric field, we highlight some nontrivial microscopic molecular features of the systems, such as the reorganization of the dipolar solvent, clustering of the ions, and diffusions of ions and dipolar solvent molecules. Particularly, our simulation indicates the nonmonotonic dependence of the ionic clustering and ion diffusion rates on the dipolar nature of the solvent molecules, as well as the amplification of these tendencies caused by the electric field application. This work provides insights into the fundamental understanding of physicochemical properties for ion-containing liquids and contributes to the design and development of ion-containing materials.

The Tianlai Cylinder Pathfinder is a radio interferometer array designed to test techniques for 21 cm intensity mapping in the post-reionization Universe, with the ultimate aim of mapping the large scale structure and measuring cosmological parameters such as the dark energy equation of state. Each of its three parallel cylinder reflectors is oriented in the north-south direction, and the array has a large field of view. As the Earth rotates, the northern sky is observed by drift scanning. The array is located in Hongliuxia, a radio-quiet site in Xinjiang, and saw its first light in September 2016. In this first data analysis paper for the Tianlai cylinder array, we discuss the sub-system qualification tests, and present basic system performance obtained from preliminary analysis of the commissioning observations during 2016-2018. We show typical interferometric visibility data, from which we derive the actual beam profile in the east-west direction and the frequency band-pass response. We describe also the calibration process to determine the complex gains for the array elements, either using bright astronomical point sources, or an artificial on site calibrator source, and discuss the instrument response stability, crucial for transit interferometry. Based on this analysis, we find a system temperature of about 90 K, and we also estimate the sensitivity of the array., 28 pages, 30 figures

Considerable efforts have been devoted to decipher the late Quaternary moisture and thermal evolution of arid central Asia. However, disparate interpretations still exist concerning different proxies. The spatial and temporal heterogeneities have inhibited a holistic understanding of general patterns and underlying mechanisms. To address these issues, two parallel cores (ONW I, 6.00 m; ONW II, 13.35 m) were retrieved in the Gobi Desert of Mongolia from lake Orog Nuur. Multidisciplinary investigations including geomorphological mapping, radiocarbon dating, sedimentological, palynological and ostracod analyses enabled us to gain a comprehensive dataset for vegetation development and hydrological variability over the last ~45 kyr. Higher lake levels during the Marine Isotope Stage (MIS) 3 and early MIS 2 (~35–~24 kyr) were probably caused by increased precipitation. The sharp transition of Termination I (~11 kyr) is indicated by sedimentological, palynological, and ostracod data. During the late Pleistocene, the lower area of the Orog Nuur catchment was dominated by Artemisia steppe and gradually altered to Chenopodiaceae desert steppe in the Holocene. The early Holocene is also characterized by a relatively humid environment. The humid pulses during the MIS 3 and the early Holocene were also recorded in other archives and are possibly the trait of a larger scale phenomenon in arid central Asia. Four major harsh climatic periods were documented in the core at ~43 kyr, ~36 kyr, during the global Last Glacial Maximum, and the Younger Dryas as playa phases. Reduced westerlies' moisture transport and a retreated East Asian Summer Monsoon influence probably caused those dry phases in the Gobi Desert of Mongolia.

Tin oxide (SnO2) has been considered as a promising anode candidate for lithium ion batteries (LIBs) due to its high theoretical capacity (782 mA h g−1). However, the large volume change (>300%) and severe structural collapse during cycles are serious. Herein, we design and synthesize a composite composed of rice husk cellulose (RHC) encapsulated SnO2. The ultrafine SnO2 nanoparticles were embedded in carbon film via a facile hydrothermal approach. It is worthy of note that the proposed hydrothermal treatment plays an indispensable role in the formation of this SnO2@RHC composite. As a promising anode for lithium ion batteries, the SnO2@RHC composite exhibits a large initial discharge capacity (2090 mA h g−1) and high capacities of 930 and 587 mA h g−1 after 100 cycles, respectively, at 0.2C and even 1C. The outstanding performance may benefit from the well-designed versatile nanostructure and the synergistic effects between the SnO2 and RHC.

TiO2 hollow spheres with porous crystalline shells were synthesised by hydrothermal treatment. The as-prepared samples possessed uniform and highly crystallized morphology have exhibited excellent electrochemical performance (high specific capacities of 223 mAh g−1 at 0.5 C after 100 cycles, and 129 mAh g−1 at 5 C after 100 cycles) and high photocatalytic activity, which indicating that TiO2 hollow nanocrystals have promising values in photocatalysis and advanced Li-ion batteries. The improvement of electrochemical performance and excellent photocatalytic activity is attributed to large surface areas, small crystallite size and unique hollow sphere nanostructure. The process in this paper provides a general route to synthesis hollow nanostructures composites. The as-prepared TiO2 hollow sphere nanostructures are also of great interests in catalysis, lithium-ion batteries, separation technology and nanotechnology.

In this work, we report a new type of anode consisting of mixed detonation nanodiamonds (DNDs) and titanium dioxide (TiO2) hollow nanospheres (HNSs) for improving the specific capacity of lithium ion batteries (LIBs). Benefiting from the unique characteristics (high lithium adsorption capacity, large specific surface area and chemical inertness) of DNDs and the porous structure of TiO2 HNSs, the anode plays an important role in realizing remarkable capacity performances (with a capacity of 348.8 mA h g−1 at 0.5C after 100 cycles) and superior long-term cycle stability (with a capacity of 246.3 mA h g−1 at 5C after 800 cycles) of LIBs, which are significantly better than those of the battery with the TiO2 anode alone. The improvement can be attributed to the enhanced Li+ storing capacity and stability of the anode consisting of DNDs and TiO2 HNS.

The water environment from river to reservoir has been considered as a hybrid river-reservoir system due to pronounced environmental properties. This study investigated the distribution and potential environmental behavior of pesticides in river-reservoir system, examining 31 target pesticides in water phase from a key drinking water source (Dongjiang River). The concentrations of ∑8OCPs, ∑16OPPs and ∑7SPs with the corresponding occurrence were in the range of 107.57–340.35 ng/L (moderate level), 232.65–1197.95 ng/L (moderate level) and 125.23–245.09 ng/L (low level), respectively. Ecological risk assessments indicated that most of the pesticides posed a high level of risk to the aquatic organisms. Moreover, seasonal agricultural application, rainfall and temperature could influence the levels and compositions of ∑8OCPs, ∑16OPPs and ∑7SPs in the river system, while seasonal hydrological processes could only influence their compositions in the reservoir system. In the wet season, the levels of ∑8OCPs and ∑7SPs decreased from the river system to reservoir system probably via biogeochemical processes, while the level of ∑16OPPs decreased along the environmental gradient probably via dilution process. Additionally, longer hydraulic retention time of the reservoir system could contribute to the biogeochemical processes for OPPs and SPs exported from the river system, but it might fail to facilitate this process for OCPs. Taken together, this study highlighted that the distributions and environmental behavior of pesticides in river-reservoir system varied seasonally from river system to reservoir system.

Degradation of salicylic acid (SA) was employed to investigate the Fenton-like reaction in CeO2-H2O2 system. The adsorption and degradation behaviors of adsorbates (eg. SA, H2O2) on CeO2 were observed through the kinetics tracks. It is found that SA follows Langmuir isothermal secondary adsorption and its adsorption capacity plays a significant role in promoting Fenton-like process. The enhanced adsorption of SA in acidic environment not only benefits the degradation of SA, but also depresses the H2O2 consumption. When surface Ce3+ sites are over-occupied with highly concentrated H2O2, the reactivity of interfacial peroxide species would suffer significant decline. Photoabsorption of CeO2 in visible region emerges due to the complexation of surface cerium ions with adsorbed species. Accordingly, a visible light sensitization process initiates electrons transfer from interface species to the ceria; and therefore, the degradation of SA in CeO2-H2O2 system was promoted by visible light (λ > 420 nm) irradiation. The enhanced Fenton-like reactivity under visible light was also confirmed with DMPO-trapping EPR spectroscopy.

The activated carbon materials from the corn stalk core raw materials were prepared through the carbonization and activation process and applied as electrode in supercapacitor. The biomass carbon materials activated under different temperatures were tested by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge cycling method. The corn stalk core-derived material activated at 700 °C with the highest specific surface area (2349.89 m2 g−1) has exhibited the maximum specific capacitance of 140 F g−1. Further detailed characterization and theoretical analysis have demonstrated that the corn stalk core derived activated carbon anode material can not only enhance the capacity of supercapacitor but also realize the comprehensive utilization of corn stalks.

In this paper, rice husk was selected as raw materials to prepare activated carbon via an effective and facile method. NaOH, as an activator, plays a crucial role in forming the hierarchical porous structure in this method. These materials were characterized through X-ray diffraction (XRD), Raman spectroscopy, Nitrogen adsorption-desorption analyses, Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The electrochemical properties have varied with the changes of morphology and structure after the activation process. After 100 cycles at a rate of 0.2C, the reversible specific capacity of rice husk-derived activated carbon (denoted as RHAC) stabilized at 448 mAhg−1. In addition, the RHAC electrode delivers an excellent rate capability with the discharge capacities of 652, 477, 363, 242 and 197 mAhg−1 at 0.2C, 0.5C, 1C, 2C, 5C, respectively. Compared with the non-activated materials (denoted as RHC), the significantly improved electrochemical performance of the RHAC could be attributed to the hierarchical porous structure with more edges, defects and the enlarged surface area.

Grain size control has been a research field of great importance as it requires the exploration of material formation mechanism, a major decisive factor in obtaining material’s ideal size and structure. The purpose of this experiment was to analyse the effect of cerium ion doping concentration on the transformation of TiO2. Mixed-phase anatase and rutile were prepared for this experiment, providing means to examine the specific transformation relationships at different temperatures for a specific phase, and vice versa. The results of this experiment clearly also deduced the formation mechanism based on the third L. Pauling Principle and Ostward’s rule, and found grain effect of cerium doping on the transition of TiO2.

A novel mesoporous activated carbon (AC) derived from corn stalk core is prepared via a facile and effective method which including the decomposition and carbonization of corn stalk core under an inert gas atmosphere and further activation process with KOH solution. The mesoporous activated carbon (AC) is characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) measurements. These biomass waste derived from activated carbon is proved to be promising anode materials for high specific capacity lithium ion batteries. The activated carbon anode possesses excellent reversible capacity of 504 mAh g−1 after 100 cycles at 0.2C. Compared with the unactivated carbon (UAC), the electrochemical performance of activated carbon is significantly improved due to its mesoporous structure.

ZnO is considered as a substitute for the next generation of lithium ion battery anode materials because of its high volumetric energy density and abundant resources. In this work, we fabricate a new material that has nanorod-like ZnO distributed in a disorderly fashion on the surface of a rice husk-derived carbon skeleton. Rice husk as a carbon source is suitable for easing the pressure on the environment and improving the utilization of agricultural residues. Its unique interconnected hollow nanosphere structured skeleton provides better support for ZnO loading and electron transport. The ZnO/rice husk-based carbonaceous nanosphere composite samples were characterised by XRD, Raman, SEM and TEM. When used as an anode for lithium-ion batteries, the material exhibited promising Li storage properties and a high specific charge capacity of 920 mA h g−1 at 0.2C after 100 cycles.

Lithium-ion batteries have drawn ever-increasing attention for application in electric vehicles owing to the high energy density and long cycle life. Herein, we report a novel porous silicon/carbon composite derived from rice husk through activation and subsequent calcinations. To consolidate the structural integrity, RGO is introduced into the porous silicon/carbon composite via ultra-sonication. The final product achieves a stable capacity of 760 mA h g−1 after 80 cycles as well as the notable rate performance of 317 mA h g−1 at 1 A g−1. The enhanced electrochemical properties are attributed to the porous structure, which provides more sites for the charge/discharge process. Meanwhile, the presence of RGO effectively improves the conductivity of the composite and conserves structural integrity. All the results have demonstrated its promising applications in LIBs.

As anodes of lithium-ion batteries, transition metal oxide materials have been considerably studied due to their high theoretical specific capacities. However, their poor conductivities and the disintegration of their structures due to volume changes when charging and discharging have restricted the development of transition metal oxide anode materials in lithium-ion batteries. In this work, a novel ZnMn2O4 sphere/jute porous carbon composite material is prepared and displays a high capacity of 1501.6 mA h g−1 after 200 cycles at a current density of 0.2 C (1 C = 784 mA g−1). At a current density of 2 C, it still has a capacity of 701.9 mA h g−1 and no capacity loss for 1000 cycles. The reason for this excellent cycling stability is that the anode material has formed a special structure of ZnMn2O4 spheres composited with jute biomass porous carbon during the preparation process. Biomass porous carbon can promote charge transfer and reduce the volume change of ZnMn2O4. This work proposes an approach to prepare an environmentally friendly, high-performance lithium-ion battery anode material.

Occurrence of antibiotic resistance genes (ARGs) in animal manure impedes the reutilization of manure resources. Aerobic composting is potentially effective method for resource disposal of animal manure, but the fate of ARGs during composting is complicated due to the various material sources and different operating conditions. This review concentrates on the biotic and abiotic factors influencing the variation of ARGs in composting and their potential mechanisms. The dynamic variations of biotic factors, including bacterial community, mobile genetic elements (MGEs) and existence forms of ARGs, are the direct driving factors of the fate of ARGs during composting. However, most key abiotic indicators, including pH, moisture content, antibiotics and heavy metals, interfere with the richness of ARGs indirectly by influencing the succession of bacterial community and abundance of MGEs. The effect of temperature on ARGs depends on whether the ARGs are intracellular or extracellular, which should be paid more attention. The emergence of various controlling strategies renders the composting products safer. Four potential removal mechanisms of ARGs in different controlling strategies have been concluded, encompassing the attenuation of selective/co-selective pressure on ARGs, killing the potential host bacteria of ARGs, reshaping the structure of bacterial community and reducing the cell-to-cell contact of bacteria. With the effective control of ARGs, aerobic composting is suggested to be a sustainable and promising approach to treat animal manure.

In the arid environment, due to the scarcity of a continuous terrestrial archive, lacustrine sequences are often employed as a paleoenvironmental repository. However, numerous spatial and temporal heterogeneities exist concerning previously studied sites in arid central Asia. Furthermore, surveys using a XRF core scanning technique on lacustrine sequences retrieved in hyperarid desert settings are largely rare. Hence, two parallel sediment cores (ONW I; ONW II) were retrieved from Orog Nuur, in the Gobi Desert of Mongolia. Continuous, high-resolution elemental abundances at a 1-cm scanning step size were examined in core ONW II using XRF core scanning. To constrain the data quality, elements with high error margins relative to measured peak areas and those elements/proxies below the significance level during the multivariate statistics are excluded for environmental/provenance implications. Based on multivariate statistical evaluation, the bulk-geochemistry of the core sediments are governed by (1) grain-size composition, (2) authigenic productivity (Ca, Cl, CaCO3) in an alkaline environment, (3) allochthonous organic material (TOC and C/Natomic), and (4) terrigenous input via fluvial inflows, as well as quasi-constant aeolian input through the late Quaternary (Al, Si, K, Ti, and Fe). Disparate source lithotypes, as well as authigenic productivity of the lake system existed before and after Termination I. The Holocene was dominated by a distinct high productivity alkaline environment with more felsic and alkaline input relative to the late Pleistocene. This might be attributed to an increased hydrodynamic strength of riverine inflow and/or intensified erosion and weathering of felsic source rocks in the upper catchment of the Orog Nuur. Therefore, in order to gain a better understanding of the bulk-geochemistry of lake sediments, the coupled provenance and environmental signatures, as well as land surface processes in the catchment need to be systematically discerned. Thus, the XRF core scanning data obtained in this study would have practical and complimentary merit for other lacustrine studies focused on the desert realm across the globe.

Disordered carbons are widely used as anode materials for lithium-ion batteries due to their stable cycle performance, high specific capacity and negative redox potentials. Among them, as an environmental friendly renewable source, biomass has attracted much attention for its application in the preparation of disordered carbon. We report a novel carbonaceous material with interconnected hollow nanosphere structure which used cellulose extracted from rice husk (RH) as a precursor and prepared through hydrothermal carbonization and high temperature calcination. When used as anodes for lithium-ion batteries, the first discharge specific capacity is as high as 1040 mAhg−1 at a rate of 0.2 C and the reversible specific capacity stabilized at 489 mAhg−1 after 100 cycles. The novel disordered nanostructure material displays superior Lithium-ion battery performance with large reversible capacities, excellent cyclic performance, and outstanding rate capability, highlighting the importance of hollow interconnected structure for maximum utilization of electrochemically active for energy storage applications in high-performance lithium-ion batteries.

The Tianlai Dish Pathfinder Array is a radio interferometer designed to test techniques for 21~cm intensity mapping in the post-reionization universe as a means for measuring large-scale cosmic structure. It performs drift scans of the sky at constant declination. We describe the design, calibration, noise level, and stability of this instrument based on the analysis of about $\sim 5 \%$ of 6,200 hours of on-sky observations through October, 2019. Beam pattern determinations using drones and the transit of bright sources are in good agreement, and compatible with electromagnetic simulations. Combining all the baselines, we make maps around bright sources and show that the array behaves as expected. A few hundred hours of observations at different declinations have been used to study the array geometry and pointing imperfections, as well as the instrument noise behaviour. We show that the system temperature is below 80~K for most feed antennas, and that noise fluctuations decrease as expected with integration time, at least up to a few hundred seconds. Analysis of long integrations, from 10 nights of observations of the North Celestial Pole, yielded visibilities with amplitudes of 20-30~mK, consistent with the expected signal from the NCP radio sky with $, 30 pages, 38 figures

As a biomass waste, hemp stems have the advantages of low cost and abundance, and it is regarded as a promising anode material with a high specific capacity. In this paper, activated carbon derived from hemp stems is prepared by low-temperature carbonization and high-temperature activation. The results of characterizations show the activated carbon has more pores due to the advantages of natural porous structure of hemp stem. The aperture size is mainly microporous, and there are mesopores and macropores in the porous carbon. The porous carbon has an excellent reversible capacity of 495 mAh/g after 100 cycles at 0.2 °C as the anode of lithium-ion battery. Compared with the graphite electrode, the electrochemical property of activated carbon is significantly improved due to the reasonable distribution of pore size. The preparation of the activated carbon provides a new idea for low cost and rapid preparation of anode materials for high capacity lithium-ion batteries.

Tin dioxide (SnO2) has a wide range of sources and high specific capacity, it is a forward-looking measure to use it as a lithium-ion battery anode, whereas its performance will hampered rapidly due to large volume expansion in practical applications. In this paper, based on the concept of environmental protection and green experiment, sunflower seed shell was used as raw material, biomass carbon microspheres were synthesized by hydrothermal method, and compounded with SnO2 nanoparticles in a certain proportion. Green biomass-derived carbon submicron spheres and their cross-linked structures can not only shorten the lithium ion transport path, but also reduce the structural damage caused by lithium ion intercalation. In particular, under the premise of carefully controlling the reaction time, those obtained after the reaction time for 24 h presented a promising Li storage properties and electrochemical performance with an excellent high-rate cycling stability of 590.5 mAh g−1 at 1C after 150 cycles. And it can still charge and discharge stably after 100 cycles at 0.2C and has a remarkable specific capacity of 959.2 mA h g−1.

Traffic flow prediction is the foundation of many applications in smart cities, and the granular precision of traffic flow prediction has to be enhanced with refined applications. However, most of the existing researches cannot meet these requirements. In this paper, we propose a spatial-temporal attention based fusion network (ST-AFN), for lane-level precise prediction. This seq2seq model consists of three parts, namely speed process network, spatial encoder, and temporal decoder. In order to exploit the dynamic dependencies among lanes, attention mechanism blocks are embedded in those networks. The application of deep spatial-temporal information matrix results in progresses in term of reliability. Furthermore, a specific ground lane selection method is also proposed to ST-AFN. To evaluate the proposed model, four months of real-world traffic data are collected in Xiaoshan District, Hangzhou, China. Experimental results demonstrate that ST-AFN can achieve more accurate and stable results than the benchmark models. To the best of our knowledge, this is the first time that a deep learning method has been applied to forecast traffic flow at the lane level on urban ground roads instead of expressways or elevated roads.

Jute fiber has been used as carbon precursor to prepare micro-mesoporous carbon material applying as anode materials for lithium ion battery. The main step was to use different quantity of zinc chloride as an activator under the carbonization at high temperature in the air atmosphere, and then an activated carbon material with prosper porosity and high specific surface area of 1028.614 m2 g−1 was obtained and named JFAC. The obtained micro-mesoporous structure benefits the lithium transfer in the active anode material. The impact of JFACs on the electrochemical performance was evaluated, showing its outstanding cycle stability and specific capacity with 742.7 mA h g−1 after 100 cycles at 0.2C. A discussion of the quantity of zinc chloride activator was exhibited and this method finally shows the high efficiency of zinc chloride for the activation of biomass carbon materials.

Coagulation has been accepted as a cost-effective and environmental-friendly method to remove pollutants. In our recent work, two coagulants of polyaluminum chloride (PAC) and polyaluminum ferric chloride (PAFC) with dosage gradients, and one coagulant aid of anionic polyacrylamide (PAM) were used to investigate their potential to remove particle-associated (PA) and free-living (FL) ARGs and MGEs detected by high throughput qPCR (HT-qPCR) method. The results indicated that the maximum removal efficiencies of PA- and FL-ARGs (4.67- and 3.18-logs) were obtained at the PAFC dosage of 50.0 mg/L. Excessive PAFC dosage can hamper the removal of size-fractionated ARGs. As PAC aid, anionic PAM (1.0 mg/L) had limited effects to promote the removal of PA-ARG, while FL-ARG removal was enhanced by 0.34 log at the PAC dosage of 50.0 mg/L. The fitted curves suggested that the optimal chemical dosages of PAC, PAFC and PAC coupled with PAM in the removal of total ARGs and MGEs were 40.5, 64.7 and 50.0 mg/L, respectively. In addition, we found that much more coagulants were needed to remove FL-ARGs compared to that of PA-ARGs. The removal efficiencies of size-fractionated ARGs by flocculation can be affected by coagulant type, dosage, coagulant aid, Zeta potential and microorganism lifestyle (PA or FL).

The one-dimensional hollow nanostructure can effectively decrease the diffusion distance of lithium ions and alleviate the volume change of SnO2 during cycling. In this work, SnO2/ZnO hollow nanotubes were obtained from two different molecular weights of Polyvinylpyrrolidone (PVP) by combining electrospinning technology and heat treatment. Mechanism studies indicated the hollow nanotubes with different morphology could be controllable by varying the molecular weight of PVP. SnO2/ZnO nanotubes with high molecular weight PVP as precursor (SnO2/ZnO–H) had smaller diameter and denser structure, which as anode showed better stability and capacity in electrochemical test. The conductivity and stability of SnO2/ZnO–H were further improved after coated with Polypyrrole (PPy) by the in-situ polymerization. The reversible capacity of the batteries was improved, and the volume expansion of the metal oxide was restrained during charging and discharging. The SnO2/ZnO@PPy anode exhibited a high discharge capacity of 626.1 mA h g−1 of 0.2C after 100 cycles, showing an outstanding stability. Therefore, controllable hollow metal oxide nanotubes structures could be obtained via different the molecular weights of precursor polymer. And the hollow nanotubes after coating by PPy as anode materials exhibited the excellent electrochemical performance. This research provided an idea in further design and optimization of anode microstructure for lithium-ion batteries.

Anatase TiO2 anchored on graphene oxide (GO) can be synthesized through a one-step hydrothermal method. The as-formed nanohybrid has a unique hollow structure and a large surface area. More importantly, compared to the pristine TiO2 counterpart, TiO2@RGO composite materials as anodes in lithium-ion batteries have demonstrated a uniform and highly crystallized morphology and exhibited excellent cycling stability and rate capability of 352 mA h g−1 at 0.5C and 223 mA h g−1 at 5C after 100 cycles, indicating that the TiO2@RGO nanocomposite has promise in advanced Li-ion batteries. The improvement of electrochemical performance is assigned to the enhanced conductivity in the presence of GO in the TiO2@RGO nanocomposite, the anatase and TiO2–B mixed crystal phase of the hollow sphere TiO2@RGO nanocomposite, the small size of TiO2 particles in the nanocomposite, and the enlarged electrode/electrolyte contact area, leading to more active sites in TiO2@RGO.

TiO2 has poor photocatalytic performance when synthesised using traditional processes under visible light, which has limited its practical applications. In this work, titanium sulfate and hydrazine hydrate were used as raw materials to fabricate highly mesoporous honeycomb TiO2via a two-step hydrothermal and calcination method. The formation mechanism of the highly mesoporous TiO2 was analyzed based on experiments and theories. The parameters were flexible using the preparation method. Samples with high photocatalytic performance can be obtained without strictly controlling the process parameters such as hydrazine hydrate dosage, the hydrothermal temperature and so on. The preparation process was as follows: the raw materials were prepared at 180 °C for 48 h in the first hydrothermal stage, and then synthesized at 150 °C for 48 h in the second hydrothermal process. The hydrazine hydrate dosage was 10 ml in the second process. The prepared grain sizes were about 16.4 nm and the specific surface areas were approximately 105.12 m2 g−1 after the samples were heated at 450 °C for 4 h. Their degradation rate was 1.8 times that of P25. The improved performances are ascribed to the unique point defects because of nitrogen atom doping in the TiO2 and the highly mesoporous structure increased by adding hydrazine hydrate.

Considerable efforts have been dedicated to desertification research in the arid and semi-arid drylands of central Asia. However, there are few quantitative studies in conjunction with proper qualitative evaluation concerning land degradation and aeolian activity in the alpine realm. In this study, spectral information from two Landsat-5 TM scenes (04.08.1994 and 28.07.2009, respectively) was combined with reference information obtained in the field to run supervised classifications of eight landscape types for both time steps. Subsequently, the temporal and spatial patterns of the alpine wetlands/grasslands evolutions in the Zoige Basin were quantified and assessed based on these two classification maps. The most conspicuous change is the sharp increase of ~627 km2 degraded meadow. Concerning other land-covers, shallow wetland increases ~107 km2 and aeolian sediments (mobile dunes and sand sheets) have an increase of ~30 km2. Considering the deterioration, an obvious decrease of ~440 km2 degraded wetland can be observed. Likewise, decrease of deep wetland (~78 km2), humid meadow (~80 km2) and undisturbed meadow (~88 km2) were determined. These entire evolution matrixes undoubtedly hint a deteriorating tendency of the Zoige Basin ecosystem, which is characterized by significantly declined proportion of intact wetlands, meadow, rangeland and a considerable increase of degraded meadow and larger areas of mobile dunes. In particular, not only temporal alteration of the land-cover categories, the spatial and topographical characteristics of the land degradation also deserves more attention. In the alpine rangelands, the higher terraces of the river channels along with their slopes are more liable to the degradation and desertification. This tendency has significantly impeded the nomadic and agriculture activities. The set of anthropozoogenic factors encompassing enclosures, overgrazing and trampling, rodent damaging and exceedingly ditching in the wetlands are assumed to be the main controlling mechanisms for the landscape degradation. A suite of strict protection policies is urgent and indispensable for self-regulation and restoration of the alpine meadow ecosystem. Controlling the size of livestock, less ditching in the rangeland, and the launching of a more strict nature reserve management by adjacent Ruoergai, Maqu and Hongyuan Counties would be practical and efficacious in achieving these objectives.

This article deduces the formation mechanism of hollow TiO2(B) nanocrystals by Oriented Attachment and Kirkendall effect. Charge density distribution and total energy can be calculated using SCC-DV-Xα-ECM. The diameter of the hollow nanocrystals is about 10–18 nm and the wall thickness of hollow nanocrystals is about 3–5 nm. The dimensions are smaller than other previous reports. In addition, their best discharge specific capacity has already reached nearly 360 mAhg−1 at 0.2 C. Comparing with other structures of TiO2(B), the hollow nanocrystals have a high rate capability and stable cycling.

To enhance the photocatalytic efficiency of TiO2, different concentration of Ce3+-doped TiO2 nanotubes were prepared using a sol-gel method combined with a hydrothermal process. After being calcined at 450°C, the morphology, composition, and crystal structures were investigated by SEM, TEM, XRD, and EDS. The samples' photocatalytic performance was characterized by degrading methylene blue under illumination of a 250 W UV-light. The result showed that both ends of the nanotubes were ringent and consisted of many layers. Their length could reach to hundred nanometers and the thickness of the walls was about 9 nm. The low-concentration Ce3+ did not influence the nanostructure and crystal structure but has a large correlation with the photocatalytic efficiency. The sample with the concentration of 1.5% performed best in photocatalytic reaction.

The mesoporous TiO2 nanoflakes have been prepared by the hydrothermal method, which is using Ti(SO4)2 as the titanium raw and KOH solution as alkaline medium. The TiO2 nanoflakes have been characterizated by transmission electron microscopy, X-ray powder diffraction, N2 adsorption–desorption analysis, cyclic voltammetry, and cycle performance test. Electrochemical performance test shows that mesoporous TiO2 nanoflakes have high discharge specific capacity and good cycle performance. Discharge specific capacity for the first time is in 0.2 C ratio of 278.1 mAh g−1. After 90 cycles, the discharge capacity reduces to 97.6% of the theoretical specific capacity.

Geochemical characteristics have been intensively used to assign sediment properties to paleoclimate and provenance. Nonetheless, in particular concerning the arid context, bulk geochemistry of different sediment archives and corresponding process interpretations are hitherto elusive. The Ejina Basin, with its suite of different sediment archives, is known as one of the main sources for the loess accumulation on the Chinese Loess Plateau. In order to understand mechanisms along this supra-regional sediment cascade, it is crucial to decipher the archive characteristics and formation processes. To address these issues, five profiles in different geomorphological contexts were selected. Analyses of X-ray fluorescence and diffraction, grain size, optically stimulated luminescence and radiocarbon dating were performed. Robust factor analysis was applied to reduce the attribute space to the process space of sedimentation history. Five sediment archives from three lithologic units exhibit geochemical characteristics as follows: (i) aeolian sands have high contents of Zr and Hf, whereas only Hf can be regarded as a valuable indicator to discriminate the coarse sand proportion; (ii) sandy loess has high Ca and Sr contents which both exhibit broad correlations with the medium to coarse silt proportions; (iii) lacustrine clays have high contents of felsic, ferromagnesian and mica source elements e.g., K, Fe, Ti, V, and Ni; (iv) fluvial sands have high contents of Mg, Cl and Na which may be enriched in evaporite minerals; (v) alluvial gravels have high contents of Cr which may originate from nearby Cr-rich bedrock. Temporal variations can be illustrated by four robust factors: weathering intensity, silicate-bearing mineral abundance, saline/alkaline magnitude and quasi-constant aeolian input. In summary, the bulk-composition of the late Quaternary sediments in this arid context is governed by the nature of the source terrain, weak chemical weathering, authigenic minerals, aeolian sand input, whereas pedogenesis and diagenesis exert only limited influences. Hence, this study demonstrates a practical geochemical strategy supplemented by grain size and mineralogical data, to discriminate sediment archives and thereafter enhance our ability to offer more intriguing information about the sedimentary processes in the arid central Asia.

In this research, we separated cellulose from wheat straw by chemical treatment, and then coated it around the ultrafine nano-size SnO2 by a hydrothermal method to form a unique carbon coating. The elastic feature of carbon supports could provide a cushion effect against the volume strain and increase the electrical conductivity of the nanocomposite material. Additionally, two non-metal elements, nitrogen and sulfur have been added to the composite to form chemical bonds with the external amorphous carbon of composite material, which leading to a further improved electrochemical performance. The final synthesized composite material was named SnO2@WSC, when used as an anode for lithium-ion batteries, the specific discharge capacity of SnO2@WSC in the first cycle reached 1750 mA hg−1. And after 200 cycles, the discharge specific capacity reached 1130 mA hg−1 and 1100 mA hg−1 at 0.2C and 1C current respectively, which exhibits superior cycle stability.

In this work, a unique nanocomposite of zinc-cobalt bimetallic sulfide and reduced graphene oxide (Zn0.76Co0.24S@rGO) is synthesized by a simple water bath-hydrothermal-sulfurization-annealing process. The designed nanomaterials have high theoretical capacity and excellent electrical conductivity of sulfide as well as excellent mechanical stability of reduced graphene oxide. When evaluated as the anode material for LIB, Zn0.76Co0.24S@rGO nanomaterial shows a high reversible capacity of 989 ​mAh g− 1 ​at a current density of 100 ​mA g− 1 after 100 cycles. The significant improvement in the electrochemical performance of Zn0.76Co0.24S@rGO nanocomposite anode can be attributed to the strong synergy between Zn0.76Co0.24S and reduced graphene oxide nanosheets, and the phase transition or alloying reaction of metal sulfides provides a higher theoretical capacity during lithium ion storage.

Ultrafine SnO2 nanoparticles anchored in porous corn straw carbon as an anode material of Li-ion batteries are synthesized via a facile hydrothermal method. The unique three-dimensional porous structure of corn straw carbon provides ideal accommodation for SnO2 (SnO2/P-CSC), and effectively alleviates the free expansion of SnO2 during charging-discharging process. The SnO2/P-CSC composite exhibits a high capacity of 648 mA h g−1 after 100 cycles at 0.2 C. In particular, compared with porous corn straw carbon (P-CSC) and pure SnO2, the capacity of SnO2/P-CSC is 1.6 times of P-CSC and 2.7 times of SnO2 respectively. The high-performances may benefit from the 3D structure of P-CSC and the synergistic effects between the SnO2 and P-CSC. The as-proposed synthetic strategy not only provides a new scalable application for corn straw carbon as a sustainable anode but also solves the serious volume expansion problem of SnO2.

With the rapid construction of dams worldwide, reservoir system has become a representation of modern aquatic environment. However, the profiles of antibiotic resistance genes (ARGs) and associated factor influencing their dynamics in modern aquatic environment (e.g., water phase, sediment phase, and soil phase) are largely unknown. Here, we comprehensively characterized the diversity, abundance, distribution of ARGs in a large drinking water reservoir using high-throughput quantitative PCR, as well as ranked the factors (e.g., mobile genetic elements (MGEs), bacteria community, bacterial biomass, antibiotics, and basic properties) influencing the profiles of ARGs on the basis of structural equation models (SEMs). Water phase was prone to harbor more diverse ARGs as compared to sediment phase and soil phase, and soil phase in drawdown area was a potential reservoir and hotspot for ARGs. Environmental media partially affected the ARG diversity in modern aquatic environment, while it observably influenced the distributions of ARGs and MGEs and their co-occurrence patterns. The pathways for the proliferation and spread of ARGs in water phase were both the horizontal gene transfer (HGT) and vertical gene transfer (VGT), while the dominant pathways in sediment phase and soil phase were the HGT and VGT, respectively. The SEMs demonstrated that MGEs contributed the most to drive the ARG dynamics in both water phase and sediment phase, while the most dominant factor for this in soil phase was bacterial community. Overall, environmental media exerted a bottleneck in driving the dynamics of ARGs in modern aquatic environment probably via diversifying the MGEs, bacterial community, bacterial biomass, antibiotics and basic properties.

Drinking water reservoir is threatened globally due to anthropogenic contamination and thus in need of more attention. Here, we comprehensively investigated the occurrence, distribution and risk assessment of representative antibiotics in a large drinking water reservoir (Fengshuba Reservoir, China). The total concentrations of antibiotics in the water phase, porewater phase, sediment phase and soil phase (drawdown area) were in the ranges of 195–569 ng/L, 47.1–333 ng/L, 114–272 μg/kg and 2.84–77.2 μg/kg, respectively. The dominant antibiotic was CIP in both the water and porewater phases, while it was OTC in the sediment phase. For the water phase, seasonal factor consisting hydrologic condition and pattern of antibiotic use could influence the occurrence level and environmental fate of antibiotics. In contrast, exogenous particles derived from the soils that had used manures during the spring planting season coupled with heavy rainfall was responsible for the occurrence level and composition of antibiotics in the sediment phase. Moreover, Chl-α, NO3−, TP and EC were the most dominant factor influencing the antibiotic distributions in the water phase, porewater phase, sediment phase and soil phase, respectively. Pseudo-partitioning coefficients indicated that PENV and PENG might accumulate more easily into the sediments from the aqueous phase compared with other antibiotics. Risk assessments suggested that TC might pose high risks to the aquatic ecosystem, but the antibiotics presented no risk to the health of consumers. Generally, TC could be used as a promising indicator for evaluating the occurrence and potential risk of antibiotics in Fengshuba Reservoir.

Antibiotic resistome is a raising concern around the world, especially considering treated wastewater for reclamation. A wastewater reclamation system (WWRS), composed by a treatment system (TS) and a reclamation system (RS) with supplementation from the treated effluent and considered as an integrated system of treatment and reclamation, was selected in this study. High-throughput qPCR (HT-qPCR) was applied to profile 283 antibiotic resistance genes (ARGs) and 12 mobile genetic elements (MGEs) in the WWRS. A total of 251 ARG and 12 MGE subtypes were detected in the WWRS. The TS exhibited good performance for the removal of ARGs with the number, relative abundance and absolute abundance of ARGs largely decreased (99.07% removal efficiency) in the final effluent, which might be ascribed to biosolid sedimentation. Enhancement of biosolids removal contributed the lessening of ARGs. In the RS, high quality effluent significantly reduced the number and abundance of ARGs along the flow to downstream. MGEs were less reduced in the treated effluent than that of the influent (R2 = −0.16, p > 0.05), and exhibited close connection with ARGs. Arcobacter, Cloacibacterium, Cyanobacteria, Acinetobacter, Flavobacterium and Dechloromonas were the relatively abundant genera in the WWRS, and exhibited significantly correlation with ARGs. Microbial communities and MGEs contributed 65.64% to the changes of ARGs. These two factors may be the main drivers of ARG proliferation in the WWRS. Thus, attention should be paid to MGEs and those abundant genera when considering treated wastewater for reclamation.

In this work, we report an anode material consisting of three-dimensional porous-carbon, nanometer-sized ZnO and Si nanoparticles to realize the high-performance lithium ion batteries. The composite powders are prepared following the processes of fabricating ZnO precursor by co-precipitation, hydrothermal reaction of mixed ZnO/SiO/porous-carbon powders, and subsequent neutralization and roast treatments. Using the hybrid anode material, the enhanced capacity performance (more than 900 mA h g−1 at 0.2 C after 300 cycles) and remarkable long-term cycle stability (more than 500 mA h g−1 at 2 C after 300 cycles) are achieved, which are significantly higher than that of using ZnO or graphite alone as anode. The improvement is ascribed to the synergistic effect of the highly conductive and large surface area porous-carbon, three-dimensional ZnO nanorods, and high adsorption of Li+ of Si particles.

We propose a green and sustainable development method to convert corn straw into porous carbon nanospheres for lithium ion battery electrode materials. Biomass porous carbon nanospheres were synthesized by high-temperature carbonization and activation using corn straw. Through the comparison of different activator, it is found that the carbon nanospheres activated by CaCl2 can not only retain the spherical structure, but also obtain rich porous, thereby enabling excellent electrochemical performance (546 mA h g−1 at the end of 100 cycles at 0.2C). The porous carbon nanospheres from low-cost and non-pollution corn straw cellulose are ideal candidate for the negative electrode material of lithium ion batteries.

The Tianlai Pathfinder is designed to demonstrate the feasibility of using a wide field of view radio interferometers to map the density of neutral hydrogen in the Universe after the Epoch of Reionizaton. This approach, called 21~cm intensity-mapping, promises an inexpensive means for surveying the large-scale structure of the cosmos. The Tianlai Pathfinder presently consists of an array of three, 15~m $\times$ 40~m cylinder telescopes and an array of sixteen, 6~m diameter dish antennas located in a radio-quiet part of western China. The two types of arrays were chosen to determine the advantages and disadvantages of each approach. The primary goal of the Pathfinder is to make 3D maps by surveying neutral hydrogen over large areas of the sky %$20,000 {\rm deg}^2$ in two different redshift ranges: first at $1.03 > z > 0.78$ ($700 - 800$~MHz) and later at $0.21 > z > 0.12$ ($1170 - 1270$~MHz). The most significant challenge to $21$~cm intensity-mapping is the removal of strong foreground radiation that dwarfs the cosmological signal. It requires exquisite knowledge of the instrumental response, i.e. calibration. In this paper, we provide an overview of the status of the Pathfinder and discuss the details of some of the analysis that we have carried out to measure the beam function of both arrays. We compare electromagnetic simulations of the arrays to measurements, discuss measurements of the gain and phase stability of the instrument, and provide a brief overview of the data processing pipeline., 18 pages, 10 figures

Porous biomass carbon derived from corn stalks was prepared via carbonization and activation of CaCl2. Combined with its microstructure, the formation mechanism and electrochemical properties were analyzed. The addition of CaCl2 was the key factor to form the porous structure, and the proportion of CaCl2 had a significant impact on the pores distribution and electrochemical properties. The resulting sample had a specific surface area of 370.6 m2 g−1 and an average pore size of 9.65 nm. The sample was circulated at 0.2C for 100 cycles, the specific discharge capacity was 783 mA h g−1. After 60 cycles at different rates, when the current was restored to 0.2C again, the discharge specific capacity quickly recovered. This showed that the sample had excellent rate performance and cycle stability for lithium-ion batteries.

To improve the photocatalytic property of TiO2, Fe3+-doped TiO2 nanotubes were fabricated by sol-gel and hydrothermal method. The prepared materials were characterized by XRD and TEM techniques. The photocatalytic properties of samples were evaluated based on the degradation of aqueous methylene blue solution under visible light. The obtained anatase-type titania nanotubes were hollow scrolls with outer diameter approximately 13 nm and length about 90–120 nm. The results showed that appropriate content of ferrum ion can improve the photocatalytic activity of titanium dioxide nanotubes significantly.