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This work investigated seasonal variation of aerosol iron (Fe) solubility for coarse (>1 µm) and fine ( µm) particles at Xi'an, a megacity in northwestern China impacted by anthropogenic emission and desert dust. Total Fe concentrations were lowest in summer and were similar in other seasons for coarse particles but lowest in summer and highest in spring for fine particles; for comparison, dissolved Fe concentrations were higher in fall and winter than spring and summer for coarse particles but highest in winter and lowest in spring and summer for fine particles. Desert-dust aerosol was always the major source of total Fe for both coarse and fine particles in all four seasons, but it may not be the dominant source of dissolved Fe. Fe solubility was lowest in spring for both coarse and fine particles and highest in winter for coarse particles and in fall for fine particles. In general, aerosol Fe solubility was found to be higher in air masses originating from local and nearby regions than those arriving from desert regions after long-distance transport. Compared to coarse particles, Fe solubility was similar for fine particles in spring but significantly higher in the other three seasons, and at a given aerosol pH range, Fe solubility was always higher in fine particles. Aerosol Fe solubility was well correlated with relative abundance of aerosol acidic species, implying aerosol Fe solubility enhancement by acid processing; moreover, such correlations were better for coarse particles than fine particles in all four seasons. Fe solubility was found to increase with relative humidity and acid acidity for both coarse and fine particles at Xi'an, underscoring the importance of aerosol liquid water and aerosol acidity in regulating Fe solubility via chemical processing.

The leakage or explosion of hazardous chemicals will seriously affect the operation safety of nuclear power plants. Therefore, in the nuclear safety review, it has been clearly proposed that the environmental risks of off-site toxic chemicals should be evaluated. When calculating the toxic chemical leakage accident, as HABIT model calculation result is based on the 2 min concentration limit condition assumed in RG1.78, and the longest duration is only 7.5 min, so it cannot be applied to the safety assessment of offsite toxic hazards. This paper presents a detail analysis of the impact on toxic chemical release using modified Gaussian plume algorithm model in ALOHA. The Gaussian plume algorithm is mainly used to calculate the plume diffusion emitted by continuous point sources, assuming that its concentration distribution obeys the empirical model of normal distribution. The plume is transported downwind at an average wind speed, ignoring turbulent diffusion downwind, with vertical and horizontal lateral diffusion described by diffusion parameters. The Gaussian plume algorithm has many advantages such as high computational efficiency and simple calculation method. Therefore, it has a wide application in the field of atmospheric diffusion. Calculation shows for the chlorine and ammonia leakage accident, chlorine’s influence area is much larger than ammonia. For ammonia, safe distance is about 3.5 km, but for chlorine, hydrogen fluoride and hydrazine, with the increase of storage capacity, their safety distance change slower at 8 km, which is consistent with HAD101/04. The storage amount of liquid ammonia shows an exponential increase, indicating that for liquid ammonia, the chemical safety control distance will not exceed 3.5 km. Conclusion of this paper has a long last meaning to NPP environmental assessment and safety evaluation, and full filled area of toxic chemicals quantitative analysis.

With the continuous update and iteration of Internet information technology, the application of BIM (Building Information Modeling) technology in the fields of project management, cost and construction is becoming more and more popular. The field of project cost relies on the significant advantages of BIM technology to realize the intelligence of project cost management. It can effectively promote the horizontal information collection and vertical information interaction of different participants, and achieve a good information exchange and interaction effect. This paper combines the characteristics of China nuclear power engineering projects, applies building information modeling (BIM) technology, and integrates it into the nuclear power engineering cost software framework. This paper firstly analyzes the basic characteristics of China nuclear power engineering cost software, and puts forward the key functional requirements for existing cost software. On this basis, the basic characteristics of foreign mainstream construction cost software with BIM technology and the feasibility of its application in China is also analyzed. The model consists of two parts, namely the BIM data management platform and the functional model of the construction project budget subsystem. Among them, the BIM data management platform realizes the analysis, storage and management of IFC (Industry Foundation Class) data, and provides a user interface for specific professional fields, such as the field of construction engineering budget, while the construction engineering budget subsystem provides users with cost budgeting expertise. In addition, this paper describes in detail the method of using BIM technology to create the most used pipe network model in cost assessment. Based on Revit software, combined with the use of visual programming tools Dynamo and Revit API, the repetitive and tedious manual modeling process is automated to compete the creation of the BIM model of a large number of pipe networks in a relatively short time, and make the model carry rich engineering information. This paper establishes a basic framework suitable for China nuclear power engineering cost software, which can lay the foundation for the subsequent development of corresponding software. The pipeline network BIM establishment method proposed in this paper can greatly improve the work efficiency of traditional CAD modeling, realize seamless connection with cost assessment, and has broad engineering application prospects.

The smart grid has attracted great attention as a new energy network. The power supplier collects the total consumption data through the smart meter. The data aggregation is a common operation in smart grid. However, the majority of existing data aggregation schemes are based on homomorphic encryption, suffering from heavy computation overhead. Recently, Gope et al. put forward a masking-based data aggregation scheme in smart grid, but there are some security problems by analyzing their scheme. If one of consumption data does not arrive at the aggregator on time, the power supplier will get incorrect aggregation results. To address these issues, we propose a lightweight and fault-tolerable data aggregation scheme. It can determine which smart meters fail to upload data on time with the idea of flag bit, and then power supplier can calculate the masking value of failed smart meter. So the proposed scheme can ensure the correctness of the final aggregation result even if a smart meter fails to upload data. In addition, the proposed scheme can achieve authentication and data collection only using one round of communication interaction while other schemes need more rounds. Security proof shows that the proposed scheme can achieve indistinguishable privacy. Experimental data confirms the efficiency of the proposed scheme.

Vehicular ad hoc network (VANETs) plays a major part in intelligent transportation to enhance traffic efficiency and safety. Security and privacy are the essential matters needed to be tackled due to the open communication channel. Most of the existing schemes only provide message authentication without identity authentication, especially the inability to support forward secrecy which is a major security goal of authentication schemes. In this article, we propose a privacy-preserving mutual authentication scheme with batch verification for VANETs which support both message authentication and identity authentication. More importantly, the proposed scheme achieves forward secrecy, which means the exposure of the shared key will not compromise the previous interaction. The security proof shows that our scheme can withstand various known security attacks, such as the impersonation attack and forgery attack. The experiment analysis results based on communication and computation cost demonstrate that our scheme is more efficient compared with the related schemes.

In situ transient synchrotron Laue x-ray diffraction based on high-energy and broadband x rays under high strain-rate tensile loading was developed at a superconducting wiggler beamline at the Beijing Synchrotron Radiation Facility. A split-Hopkinson tensile bar is utilized to realize this dynamic loading condition, while the transient Laue x-ray diffraction captures the transient internal structure of monocrystalline materials. Plastic deformation of a monocrystalline nickel specimen was investigated to prove the ability of this instrumentation in the characterization of a dynamic response of monocrystalline materials during a high strain-rate impact process with 5 µs time resolution.

Deposition of anthropogenic aerosols may contribute significantly to dissolved Fe in the open ocean, affecting marine primary production and biogeochemical cycles; however, fractional solubility of Fe is not well understood for anthropogenic aerosols. This work investigated mass fractions, solubility, speciation and isotopic compositions of Fe in coal and municipal waste fly ash. Compared to desert dust (3.1 ± 1.1%), the average mass fraction of Fe was higher in coal fly ash (6.2 ± 2.7%) and lower in municipal waste fly ash (2.6 ± 0.4%), and the average Fe/Al ratios were rather similar for the three types of particles. Municipal waste fly ash showed highest Fe solubility (1.98 ± 0.43%) in acetate buffer (pH: 4.3), followed by desert dust (0.43 ± 0.30%) and coal fly ash (0.24 ± 0.28%), suggesting that not all the anthropogenic aerosols showed higher Fe solubility than desert dust. For the samples examined in our work, amorphous Fe appeared to be an important controlling factor for Fe solubility, which was not correlated with particle size or BET surface area. Compared to desert dust (-0.05‰ to 0.21‰), coal and municipal waste fly ash showed similar or even higher δ

Phytoliths are siliceous substances that are abundant within intercellular spaces and inside cells of numerous types of plants. During the formation of phytoliths, between 0.2 and 5.8% of organic carbon (C) can be occluded within the phytoliths. Phytolith-occluded C (PhytOC) in terrestrial ecosystems is a stable C sink and can be distributed in organic matter that is not strongly associated with soil minerals (LFOM) or that is strongly associated with mineral particles (forming organo-mineral complexes) (HFOM). We (1) investigated the impact of plantation age and soil depth on the size of the PhytOC pool and its distribution in soil physical fractions in Moso bamboo (Phyllostachys pubescens) forests; and (2) explore the relationship among phytoliths and PhytOC (and their fractions) concentrations and the soil properties. We used a chronosequence approach by sampling 5-, 10-, 20-, 50-, and 100-year-old Moso bamboo stands to examine the effect of plantation age on PhytOC storage and its distribution between the LFOM and HFOM pools. Our results showed that PhytOC concentration and the concentration of PhytOC in LFOM and HFOM increased with increasing stand age in the topsoil (0–30 cm) but not in the subsoil (30–100 cm). Long-term planting of Moso bamboo forests increased the soil PhytOC pool size, as well as the LFOM- and HFOM-PhytOC fractions. The LFOM- and HFOM-PhytOC concentrations were positively correlated with soil organic C concentrations. The HFOM-PhytOC concentration was positively correlated with that of water-soluble silicon. We conclude that the increasing bamboo plantation age will promote PhytOC storage in the bulk soil and physical fractions in subtropical China. Management practices that increase PhytOC input and decrease PhytOC output should be developed in the future to increase PhytOC storage in bamboo plantations.

Advanced high-strength steels are key structural materials for the development of next-generation energy-efficient and environmentally friendly vehicles. Medium Mn steel, as one of the latest generation advanced high-strength steels, has attracted tremendous attentions over the past decade due to its excellent mechanical properties. Here, the state-of-the-art developments of medium Mn steel are systematically reviewed with focus on the following crucial aspects: (a) the alloy design strategies; (b) the thermomechanical processing routes for the optimizations of microstructure and mechanical properties; (c) the fracture mechanisms and toughening strategies; (d) the hydrogen embrittlement mechanisms and improvement strategies.

The application of manure-derived biochar offers an alternative to avoid the direct application of manure to soil causing greenhouse gas emission. Soil fauna, especially earthworms, can markedly stimulate carbon dioxide (CO2) and nitrous oxide (N2O) emissions from soil. This study therefore investigated the effect of cattle manure biochar (added at rates of 0, 2%, or 10%, coded as BC0, BC2 and BC10, respectively) application, with or without earthworm Aporrectodea turgida, on emissions of CO2 and N2O and changes of physic-chemical properties of agricultural and forest soils in a laboratory incubation experiment. The BC10 treatment significantly enhanced cumulative CO2 emissions by 27.9% relative to the untreated control in the agricultural soil. On the contrary, the BC2 and BC10 treatments significantly reduced cumulative CO2 emissions by 16.3%–61.1% and N2O emissions by 92.9%–95.1% compared to the untreated control in the forest soil. The addition of earthworm alone significantly enhanced the cumulative CO2 and N2O fluxes in agricultural and forest soils. Cumulative CO2 and N2O fluxes were significantly increased when BC2 and BC10 were applied with earthworm in the agricultural soil, but were significantly reduced when BC10 was applied with earthworm in the forest soil. Our study demonstrated that biochar application interacted with earthworm to affect CO2 and N2O emissions, which were also dependent on the soil type involved. Our study suggests that manure biochar application rate and use of earthworm need to be carefully studied for specific soil types to maximize the climate change mitigation potential of such management practices.

The use of exogenous silicon (Si) amendments, such as Si fertilizers and biochar, can effectively increase crop Si uptake and the formation of phytoliths, which are siliceous substances that are abundant in numerous plant species. Phytolith-occluded carbon (C) (PhytOC) accumulation in soil plays an important role in long-term soil organic C (SOC) storage. Nevertheless, the effects of both Si fertilizer and biochar application on PhytOC sequestration in forest plant-soil systems have not been studied. We investigated the impact of Si fertilizer and biochar applications on 1) the PhytOC pool size, the solubility of plant and soil phytoliths, and soil PhytOC in soil physical fractions (light (LFOM) and heavy fractions of organic matter (HFOM)) in Moso bamboo (Phyllostachys pubescens) forests; and 2) the relationships among plant and soil PhytOC concentrations and soil properties. We used a factorial design with three Si fertilizer application rates: 0 (S0), 225 (S1) and 450 (S2) kg Si ha−1, and two biochar application rates: 0 (B0) and 10 (B1) t ha−1. The concentrations of PhytOC in the bamboo plants and topsoil (0–10 cm) increased with increasing Si fertilizer addition, regardless of biochar application. Biochar addition increased the soil PhytOC pool size, as well as the LFOM- and HFOM-PhytOC fractions, regardless of Si fertilizer application. The Si fertilizer application increased or had no effect on soil phytolith solubility with or without biochar application, respectively. Soil PhytOC was correlated with the concentration of soil organic nitrogen (R2=0.32), SOC (R2=0.51), pH (R2=0.28), and available Si (R2=0.23). Furthermore, Si fertilizer application increased plant and soil PhytOC by increasing soil available Si. Moreover, biochar application increased soil PhytOC concentration in LFOM-PhytOC and the unstable fraction of PhytOC. We conclude that Si fertilizer and biochar application promoted PhytOC sequestration in the plant-soil system and changed its distribution in physical fractions in the Moso bamboo plantation in subtropical China.

Food safety is a top priority of concern for consumers. To promote growth, as well as to treat diseases which occur in aquaculture, antibiotics, even banned veterinary antibiotics, are widely used. This survey investigated the levels of chloramphenicol (CAP) by LC-MS/MS in 291 aquatic samples (all the products in this survey were local sales, exported products were not included), including shellfish, shrimp and fish, from Shenzhen, South China. The CAP concentrations in these samples (based on wet weight) were: shellfish (−1, mean: 68.8 µg kg−1); shrimp (−1, mean: 0.5 µg kg−1) and fish (−1, mean: 0.7 µg kg−1). The highest concentration of CAP was found in shellfish samples (Mactra veneriformis, 205 µg kg−1), these levels were greater than those reported in aquatic products from other locations in China. The detection rate of CAP was 37.2% in shellfish samples (64/172), 13.6% in shrimp samples (3/22) and 16.5% in fish samples (16/97). The detection rate of CAP in shellfish samples was higher than that in fish and shrimp samples, and therefore food safety in this region cannot be ignored. The results obtained from the current study indicated a high incidence of CAP in aquatic products in this region and argue for stronger market supervision and regulation in China.

Various DNA-modulated photosensitization schemes have been reported for various applications, but DNAzyme has not yet been included. Here, we found the DNAzyme with metal ion as cofactor could also be efficient in modulation of photosensitization process. The UO 2 2 + -specific DNAzyme can switch between double strand DNA (dsDNA) and single strand DNA (ssDNA) upon UO 2 2 + cleavage, which can regulate the photosensitization process of SYBR Green I. Coupling with photosensitization-induced chromogenic reaction (TMB oxidation), a simple colorimetric sensor for UO 2 2 + was developed accordingly. To increase the visual resolution of the proposed assay, a background color was supplied. Compared with the previous DNAzyme-based UO 2 2 + sensors, the proposed assay featured label-free and simple. Besides, the tolerance for high salinity of this assay is appealing. The proposed assay offered a detection limit of 0.08 μg/L with UV−vis detection and 0.5 μg/L with the naked eye. With the proposed colorimetric assay, UO 2 2 + levels in the range of 0.7–1.2 μg/L (2.9–5.0 nM) were identified in high salinity seawater samples, with spike-recoveries ranging from 93% to 104%.

H2 O2 and horseradish peroxidase (HRP) are commonly used together in bioassays. HRP is required to accelerate the reaction between a chromogenic substrate (e.g., 3,3',5,5'-tetramethylbenzidine, TMB) and H2 O2 , and thus amplifies the signal. Herein, molecular oxygen for enzyme-free and H2 O2 -free oxidation is explored, still using the same colorimetric reaction. Restricted by spin selection rules, the ground-state triplet oxygen needs to be converted to the singlet state to oxidize TMB. Phloxine B (PB) is used as the photosensitizer because of its excellent performance and safety. Under green light irradiation, each PB has a turnover of approximately 51 TMB molecules in 20 min, making PB a "molecular enzyme mimic" for signal amplification. With its small size, multiple PB molecules are loaded on a graphene oxide nanosheet to design a modified enzyme-linked immunosorbance (ELISA) assay (termed photosensitization immunosorbent assay, PISA), improving the 1:1 enzyme/target ratio to n:1. PISA is more sensitive for carcinoembryonic antigen than a commercial ELISA kit, and successfully measures the antigen in the serum of multiple cancer patients. This simple and green method of oxidation coupled with the small size of the photosensitizer and graphene oxide may enable many other applications in biosensor development, smart materials, and energy harvesting.

In the present study, we investigated the effects of morphology, tension and vibration on the wettability of graphene by performing classical molecular dynamics simulations. The contact angle of water droplet on ideal graphene is calculated to be 88.27° using the density profile method, which is in good agreement with the experimental data. The wrinkled morphology slightly decreases the wettability of graphene in most cases, and the droplet contact line always prefers to stay at the crest of wrinkles. The wrinkled morphology also brings extra barrier energy which leads to the pinning effect and discretized wetting effect with the droplet contact angle fluctuating up and down when the droplet volume increases. Tension and vibration strongly influence the wettability of graphene. The droplet contact angle linearly increases with increasing of biaxial tensile strain when the stain is lower than 10%, then remains at about 110°. The graphene becomes more and more hydrophobic with increasing of vibrational amplitude and decreasing of vibrational period. The contact angle of droplet on vibrational graphene and corresponding vibrational energy of graphene can be described by a logarithmic function.

The article describes a bienzyme visual system for aptamer-based assay of Hg(II) at nanomolar levels. The detection scheme is based on the finding that Hg(II) ions captured by aptamer-functionalized magnetic beads are capable of inhibiting the enzymatic activity of uricase and thus affect the formation of H2O2 and the blue product, i.e., oxidized tetramethylbenzidine. This strategy allows for a visual detection of Hg(II) at nanomolar levels without additional amplification procedure. Measuring the absorbance at 650 nm, the logarithmic calibration plot is linear in the concentration range of 0.5–50 nM and the limit of detection (LOD) is 0.15 nM. This is as low as the LOD obtained by atomic fluorescence spectrometry (AFS). The ions K+, Mg2+, Na+, Ca2+, Cu2+, Zn2+, Fe3+, Al3+, Co2+, AsO2 −, Ni2+, Cd2+ and Pb2+ do not have a significant effect on color formation. The method was applied to the analysis of (spiked) river water, lake water, mineral water, tap water and certified reference water samples, and the results agreed well with those obtained by AFS or certified values, with recoveries ranging from 97% to 109%. The relative standard deviation for five parallel detections at a 10 nM Hg(II) level is 5.2%.

Plantation management practices could markedly change the sequestration of phytolith-occluded carbon (PhytOC) in plants and soils. However, for Moso bamboo (Phyllostachys pubescens) plantations, the effect of intensive plantation management (including fertilization, tillage, and removal of understory vegetation) on the accretion rate of PhytOC in the soil-plant system is much less understood than extensive management (without fertilization, tillage, and removal of understory vegetation). The objectives of this study were to investigate the effect of intensive and extensive management practices on the production, accumulation, and runoff of PhytOC and their distribution in physical fractions in Moso bamboo plantations. Our results showed that intensive management (1) increased PhytOC production mainly due to increased forest productivity, (2) increased PhytOC storage in the heavy fraction but decreased its storage in the light fraction of organic matter, resulting in the lack of effect on soil PhytOC storage, (3) increased the rate of dissolution of phytolith and the loss of PhytOC in runoff, and (4) promoted PhytOC sequestration in the soil-plant system, mostly in the plants, due to the greater rate of PhytOC production than the rate of loss. We conclude that intensive bamboo plantation management practices are beneficial to increasing long-term PhytOC sequestration in the soil-plant system.

Various DNA-modulated photosensitization schemes have been reported for various applications, but DNAzyme has not yet been included. Here, we found the DNAzyme with metal ion as cofactor could also be efficient in modulation of photosensitization process. The UO

An on-line molecularly imprinted solid-phase extraction (MISPE) method was developed for the capillary electrophoresis (CE) detection of bisphenol A (BPA). Analyte extraction was achieved by using an in-column MISPE concentrator, which was prepared by coating the molecularly imprinted polymer (MIP) material directly in the separation capillary. The key parameters influencing the extraction efficiency, including the sample pH, extraction time, desorption solvent, and the injection duration of the desorption solution, were investigated. The combination of MISPE with CE produced a linear relationship between the CE peak areas versus the BPA concentration in the range from 3 to 300 ng mL − 1 with a limit-of-detection (LOD) as low as 0.8 ng mL − 1 . The LOD of MISPE-CE is over 100-fold lower than that of direct CE determination. The MISPE-CE method was used for the analysis of four BPA-spiked samples: tap water, river water, a beverage, and urine, with recoveries in the range of 87.2–108.3%. The MISPE-CE method features the advantages of on-line extraction, ease of atomization, and low sample consumption.

We report here the newly discovered photocatalytic activity of the dsDNA-SYBR Green I (SG) complex, which can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) under light irradiation corresponding to the excitation of the dsDNA-SG complex. The most appealing feature of the photocatalytic system here is that it can be obtained using random DNA sequences that can form a duplex. Considering the universality of the photooxidase, a label-free and universal platform was proposed for highly sensitive visual bioassays.