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In this work, through the self-developed setup for in situ electrochemical tests, the corrosion behavior of 13Cr stainless steel under the combined effect of stress and crevice in high pressure CO2/O2 environment was investigated. The results show that 13Cr stainless steel presents a self-passivation state. Under the action of stress, the anodic dissolution process of steel inside crevice is expedited. There is a galvanic effect between the stressed steel inside crevice and the unstressed steel outside crevice. The applied stress reduces the induction stage of crevice corrosion and induces a larger galvanic current, i.e., the applied stress promotes the development of crevice corrosion. Meanwhile, adding 0.1 MPa O2 is conducive to forming a more stable passive film but causes a greater galvanic effect.

A series of aromatic sulfonic acids is synthesized by subjecting arenes and NaHSO4·H2O to high-speed ball milling in the presence of P2O5. It is suggested the aromatic sulfonation occurs via in situ generated H2SO4 to give aromatic sulfonic acids. In some cases, formation of diaryl sulfones was observed.

In this paper, we study the equivalent conditions for the boundedness of the commutators generated by the multilinear maximal function and the bounded mean oscillation (BMO) function on Morrey space. Moreover, the endpoint estimate for such operators on generalized Morrey spaces is also given.

As high capacity anode materials, spinel-type transition metal oxides have a bottleneck of poor cyclic stability. Nano structure and carbon loading are common modification approaches, while the high cost is unaffordable for industrial implementation. In this study, micron scale zinc manganate was synthesized by solvothermal plus calcination process. The pomegranate-shaped ZnMn2O4 (p-ZMO) was obtained using solvent of ethylene glycol, and the microsphere-shaped ZnMn2O4 (m-ZMO) was obtained using water. During electrochemical testing, the p-ZMO anode delivered larger charge capacity of 726 mAh g‒1 at 0.2 A g‒1 than 589 mAh g‒1 of m-ZMO. Even over 1000 cycles at 1 A g‒1, the p-ZMO still maintained a reversible capacity of 506 mAh g‒1 (much higher than 372 mAh g‒1 of graphite anode), with a superior retention of 84%. It indicates that this work develops an effective strategy to prepare high-performance transition metal oxides for anode materials of lithium-ion batteries.

Single-atom metal-insulator-semiconductor (SMIS) heterojunctions based on Sn-doped Fe2 O3 nanorods (SF NRs) were designed by combining atomic deposition of an Al2 O3 overlayer with chemical grafting of a RuOx hole-collector for efficient CO2 -to-syngas conversion. The RuOx -Al2 O3 -SF photoanode with a 3.0 nm thick Al2 O3 overlayer gave a >5-fold-enhanced IPCE value of 52.0 % under 370 nm light irradiation at 1.2 V vs. Ag/AgCl, compared to the bare SF NRs. The dielectric field mediated the charge dynamics at the Al2 O3 /SF NRs interface. Accumulation of long-lived holes on the surface of the SF NRs photoabsorber aids fast tunneling transfer of hot holes to single-atom RuOx species, accelerating the O2 -evolving reaction kinetics. The maximal CO-evolution rate of 265.3 mmol g-1 h-1 was achieved by integration of double SIMS-3 photoanodes with a single-atom Ni-doped graphene CO2 -reduction-catalyst cathode; an overall quantum efficiency of 5.7 % was recorded under 450 nm light irradiation.

This paper mainly studied the problem of energy conserving in wireless sensor networks for target tracking in defensing combats. Firstly, the structures of wireless sensor nodes and networks were illustrated; Secondly, the analysis of existing energy consuming in the sensing layer and its calculation method were provided to build the energy conserving objective function; What’s more, the other two indicators in target tracking, including target detection probability and tracking accuracy, were combined to be regarded as the constraints of the energy conserving objective function. Fourthly, the three energy conserving approaches, containing optimizing the management scheme, prolonging the time interval between two adjacent observations, and transmitting the observations selectively, were introduced; In addition, the improved lion algorithm combined with the Logistic chaos sequence was proposed to obtain sensor management schemes. Finally, simulations had been made to prove the effectiveness of the proposed methods and algorithm.

Dissolved Mn(II) in the hydrothermal plume is known to be microbially oxidized to form Mn(III/IV) oxides, and the Mn oxides scavenge other trace elements in seawater. In the GEOTRACES GP16 cruise, dissolved Mn (dMn) and particulate Mn (pMn) were found to be transported over 4000 km westwards from the Southern Eastern Pacific Rise. Previous studies in this plume showed different removal rates of dMn and pMn as well as pMn size distribution between the near-field (80 km) plumes. In order to understand Mn cycling in these plumes, spatial distribution, oxidation states, and mineral structures of Mn in small size fraction (SSF; 0.8–51 μm) and large size fraction (LSF; >51 μm) particles from the near-field and far-field plumes were examined using micro X-ray fluorescence spectrometry (μ-XRF), X-ray absorption near-edge structure spectroscopy (XANES), chemical species mapping, and extended X-ray absorption fine-structure spectroscopy (EXAFS). In the near-field plume, pMn in the SSF is dominated by oxidized Mn with Mn(III) fractions of ∼30%. They are a mixture of δ-MnO₂ and triclinic birnessites that is known to be formed as a result of autocatalytic Mn(II) oxidation at the surface of freshly-formed δ-MnO₂, suggesting that both microbial and autocatalytic Mn oxidation occur in the near-field plume. The LSF pMn in the near-field plume is also oxidized and often found in large aggregates several hundreds of μm in size. These aggregates settle out in the near-field and during transport, and are not found in the far-field plume. In the far-field plume where Mn oxides are not newly formed, pMn in the SSF is oxidized, but their Mn(III) fractions are smaller than in the near-field pMn. Unlike the SSF, the far-field plume LSF pMn is dominated by reduced Mn, implying very slow aggregation of pMn in the far-field plume. The different characteristics of pMn between the near-field and far-field plumes affect its scavenging of other trace elements. In the near-field plume, Co, Mo, ²³¹Pa are associated with pMn, but not in the far-field plume. ²³¹Pa is adsorbed to pFe rather than pMn in the far-field plume, and Pb is adsorbed to pFe in the entire plume. The result shows that freshly-formed Mn oxides in the near-field plume have higher scavenging capacity than the far-field plume pMn. Our findings suggest that the mineralogical age of Mn oxides may be an important parameter that controls the scavenging of many other trace elements and isotopes.

A couple of enantiomers of 2, 6-diaminotriptycene ( R, R - 1 and S, S - 1 ) are split by chiral HPLC and their absolute configurations are identified by single-crystal X-ray diffraction technology. Using the enantiomers as monomers, a couple of chiral porous polyimides ( R - FTPI and S - FTPI ) are prepared by polycondensation reactions and display good heat stability, high BET surface area and good solubility in organic solvents. Moreover, both of R - FTPI and S - FTPI can be cast into robust, free-standing films suitable for enantioselective separation with symmetrical chiral selectivity.

As a highly toxic heavy metal, chromium has caused a certain threat to public health and livestock breeding in recent years. In poultry, as one of our most commonly consumed meat product, its health issues will seriously threaten the safety of human life. As previous studies have confirmed, when cells are stimulated by the external environment, mitochondria, as an organelle that provides energy to the cells, can cause damage and autophagy. The purpose of this study is to confirm whether Cr(VI) can cause mitophagy in cock heart. We first randomly divided 32 cocks into four groups to explore the mechanism of this effect. The cocks were then separately exposed to four different dose levels, namely, the control level and 10, 30, and 50 mg/kg levels, via daily oral intake into the body through mixed feeding for 45 days. After 45 days, we sampled and detected pathological changes and the levels of inflammatory factors (IL-6, TNF-α, and IFN-γ), mitochondrial membrane potential (MMP), adenosine triphosphatases (ATPases), and mitophagy-related proteins (LC3, p62/SQTM1, TOMM20, and Parkin). We found that IL-6, TNF-α, IFN-γ, and LC3II contents increased with the increase in Cr(VI) concentration. However, MMP, ATPases, p62/SQTM1, and TOMM20 levels decreased with the increase in Cr(VI) concentration. At the same time, Cr(VI) exposure caused heart tissue damages and Parkin translocation. In conclusion, our results proved that inflammatory damage, mitochondrial function damage, and mitophagy in cock heart tissues were dependent on Cr(VI) concentration.

To deeply understand and even describe the evolutions of the low-energy twin boundary density (BLD∑3n) in a thermal-plastic deformation process, an improved twin density model as a function of average grain size and stored energy is developed. For Nimonic 80A superalloy, the model is solved based on the EBSD statistical results of grain size and BLD∑3n in the specimens compressed at temperatures of 1273–1423 K and strain rates of 0.001–10 s–1. The corresponding relationships of BLD∑3n with stored energy and grain size varying with temperature and strain rate are clarified by the superimposed contour plot maps. It is summarized that BLD∑3n increases with increasing stored energy and decreasing grain size, and higher BLD∑3n with finer grains corresponds with lower temperatures and higher strain rates. Such relationships are described by the improved twin density model, and the prediction tolerance of the solved model is limited in 2.8%.

Despite the importance of maternally selected nests in shaping offspring phenotypes, our understanding of how the nest environment affects embryonic development and offspring traits of most non-avian reptiles is rather limited largely due to the logistical difficulty in locating their nests. To identify the relative contributions of environmental (temporal [seasonal] and spatial [nest-site]) and intrinsic (clutch) factors on embryonic development and offspring traits, we conducted a cross-fostering experiment by swapping eggs between maternally-selected nests of the toad-headed agama (Phrynocephalus przewalskii) in the field. We found that nest environment explained a large proportion of variation in incubation duration, hatching success, and offspring size and growth. In contrast, clutch only explained a small proportion of variation in these embryonic and offspring traits. More significantly, compared with spatial effects, seasonal effects explained more phenotypic variation in both embryonic development and offspring traits. Eggs laid early in the nesting season had longer incubation durations and produced smaller hatchlings with higher post-hatching growth rates than did later-laid eggs. Consequently, hatchlings from early-laid eggs reached larger body sizes prior to winter. In addition, we found that female toad-headed agama did not select nests specific to reaction norms of their own offspring because hatchlings from original or translocated nests had similar phenotypic traits. Overall, our study demonstrates the importance of seasonal variation in nest environments in determining embryonic development and offspring phenotypes, which has not been widely appreciated at least in non-avian reptiles.

A low phase noise millimeter-wave (MMW) signal generator is proposed and experimentally demonstrated with a C-band passively Fabry-Perot (F-P) quantum dot mode-locked laser. A novel method is proposed to generate low phase noise MMW signal, which is simply based on a commercial off-the-shelf dual-driven LiNbO3 Mach-Zehnder modulator and a passively F-P quantum dot mode-locked laser. MMW signal with the frequency of 30 GHz, 45 GHz and 90 GHz respectively is obtained experimentally. Single-sideband phase noise of the 30 GHz and 45 GHz MMW signal is −112 dBc/Hz and −106 dBc/Hz at an offset of 1 kHz, respectively. The linewidth of the 30 GHz and 45 GHz MMW signal is about from 225 Hz and 239 Hz. This is considered a very simple MMW generator with a quasi-tunable broadband and ultra-low phase noise.

Graphite is the mainstream anode material of commercial lithium-ion batteries, while its low theoretical capacity and short supply limit its application in the ever-increasing demand for high-capac...

In order to obtain a high removal efficiency of Cd(II) in aqueous solution, natural attapulgite (ATP) was modified with hydrochloric acid (HCl), octadecyl trimethyl ammonium chloride, nitrilotriacetic acid (NTA), and ethanediamine (EDA) to develop an effective Cd(II) adsorbent. The characteristics of the modified adsorbents and the natural ATP were characterized using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. The adsorption kinetics of Cd(II) in aqueous solution were well described by a pseudo-second-order kinetic equation, and the sorption isotherm most closely followed the Langmuir model. Complexation was determined to be the main adsorption mechanism. Among the four modified ATPs, EDA-ATP (ATP modified by EDA) showed the best adsorption capacity for Cd(II), reaching 10.55 mg g−1, which was 115 and 27 percentages higher than the capacity of the unmodified ATP and NTA-ATP (ATP modified by NTA), respectively. The ionic strength and pH of the initial solution had no significant impact on the adsorption capacities of Cd(II) onto EDA-ATP. The EDA-ATP loaded with Cd(II) could be regenerated easily by acid treatment. These results give an available choice for the effective and recyclable Cd(II) ions sorbents from water.

In order to deeply understand the grain growth behaviors of Ni80A superalloy, a series of grain growth experiments were conducted at holding temperatures ranging from 1223 to 1423 K and holding time ranging from 0 to 3600 s. A back-propagation artificial neural network (BP-ANN) model and a Sellars model were solved based on the experimental data. The prediction and generalization capabilities of these two models were evaluated and compared on the basis of four statistical indicators. The results show that the solved BP-ANN model has better performance as it has higher correlation coefficient (r), lower average absolute relative error (AARE), lower absolute values of mean value (μ) and standard deviation (ω). Eventually, a response surface of average grain size to holding temperature and holding time is constructed based on the data expanded by the solved BP-ANN model, and the grain growth behaviors are described.

Let A be an artin algebra. An A-module M is semi-Gorenstein-projective provided that Exti(M,A) = 0 for all i ≥ 1. If M is Gorenstein-projective, then both M and its A-dual M∗ are semi-Gorenstein projective. As we have shown recently, the converse is not true, thus answering a question raised by Avramov and Martsinkovsky. The aim of the present note is to analyse in detail the modules M such that both M and M∗ are semi-Gorenstein-projective.

To understand the genetic diversity and dispersal history of Schlegel’s Japanese gecko (Gekko japonicus), we performed genetic analyses and paleo-species distributional modelling. For the genetic analysis, we analyzed mitochondrial DNA (mtDNA) (cytochrome b [Cytb] and NADH dehydrogenase 2 [ND2]) and seven microsatellite loci of 353 individuals from 11 populations (2 east coast China, 4 west and central coast Japan and 5 Korea). For the paleo-species distribution modelling, we used 432 occurrence data points (125 China, 291 Japan and 16 Korea) over the Pleistocene and Holocene. China is inferred to be the source population, which had higher genetic diversity (mtDNA) and more private alleles (mtDNA) compared to Japanese and Korean populations. Differences between the three counties were very small in the mtDNA haplotype network despite some genetic structure among the three countries. Microsatellite analysis inferred that genetic exchange has actively occurred among the Chinese, Japanese and Korean populations. Suitable habitats in Japan should have been plentiful by the mid-Holocene, but have only recently become available in Korea. These results suggest that dispersal of G. japonicus occurred after the Holocene warming from the east coast of China to the west and central coasts of Japan and Korea, and gene flow is actively occurring among the three countries.

In the present study, the nanocatalyst of imidazolium based ionic liquids (ILs) is synthesized for the fixation of carbon dioxide (CO2) under moderate conditions by utilizing a balloon of CO2 with commercially available epoxides. IL incorporated porous dendritic fibrous nanosilica (DFNS) catalyst (IL/DFNS) was designed and synthesized. The synthesized catalyst was characterized using N2 absorption desorption isotherm, XPS, SEM, EDX, TGA, HR-TEM, and AFM. For cyclic carbonate, an environmental friendly catalyst of porous IL/DFNS indicate highly impressive catalytic efficiency from CO2 through CO2 fixation and epoxides under mild condition. Attendance of polar hydroxyl and anion exchange nature groups of IL frame work to high surface area is known as the main aspect to be reliable for elevated catalytic efficiency and also advance in stability of catalyst and providing a proper recyclability.

Triple oxygen isotope compositions have become one of critical proxies in characterizing a wide range of geochemical and hydroclimate processes. However, Δ17O (carbonate 17O anomaly) has only been barely used in the last decade because it is difficult to measure δ17O of natural samples to a sufficient precision in order to resolve small natural variability. In this study, we present triple oxygen isotope data from speleothems obtained by an O2-CO2 Pt-catalyzed oxygen-isotope equilibration method. The high precision (9 per meg or better, 1σ SD) of our new speleothem Δ17O data is sufficient to resolve subtle hydroclimatic signals. Based on this method, we established triple-oxygen-isotope records of TON cave in westerly region since the last 135ka, providing the evolution history of water vapor source and water vapor cycle in the orbit-millennium scale atmospheric precipitation in the Central Asia. In addition, the triple-oxygen-isotope records of speleothem from Asian and South American monsoonal regions were established in the key periods, such as glacial and interglacial periods. Our speleothem Δ17O data indicate a 20 per meg difference between Marine Isotope Stage 5d and 5e in samples from Central Asia, suggesting a shift in moisture source and/or fractionation history. Unexpectedly, there were no measurable Δ17O differences between glacial and interglacial samples from both the South American (western Amazon) and Asian (southern China) monsoon domains, implying consistent moisture-source conditions across glacial and interglacial cycles, at least in terms of relative humidity. Speleothem Δ17O data may thus provide new and important constraints for understanding regional and global hydroclimate dynamics.

The beaconless acquisition pointing and tracking (APT) system uses signal light to act as beacon. But the signal light’s divergence angle is so small that it is difficult to capture. In this work, aiming at the different requirements of divergence angle for a free-space optical-communication (FSO) system in a different working phase, we use a stepper motor for automatic focusing control in the acquisition and pointing process to change the spot size. For this purpose, we derive a formula for the average acquisition time of continuous raster scanning. The relationship between the received power and the divergence angle under the influence of the atmospheric transmission and the pointing errors is analyzed to obtain the optimum range of the divergence angle. Also the relationship between defocusing and the divergence angle of collimated beam is given. Finally, we prove by experiments that the automatic focusing control method effectively solves the contradiction of the different divergence angles between communication phase and acquisition phase.

Electro-optic (EO) modulators, which convert signals from the electrical to optical domain plays a key role in modern optical communication systems. Lithium niobate on insulator (LNOI) technology has emerged as a competitive solution to realize high-performance integrated EO modulators. In this Letter, we design and experimentally demonstrate a Mach–Zehnder interferometer-based modulator on a silicon nitride loaded LNOI platform, which not only takes full advantage of the excellent EO effect of L i N b O 3 , but also avoids the direct etching of L i N b O 3 thin film. The measured half-wave voltage length product of the fabricated modulator is 2.24 V·cm, and the extinction ratio is ∼ 20 d B . Moreover, the 3 dB EO bandwidth is ∼ 30 G H z , while the modulated data rate for on–off key signals can reach up to 80 Gbps.

Islet beta-cell viability, function, and mass are three decisive attributes that determine the efficacy of human islet transplantation for type 1 diabetes mellitus (T1DM) patients. Islet mass is commonly assessed manually, which often leads to error and bias. Digital imaging analysis (DIA) system has shown its potential as an alternative, but it has some associated limitations. In this study, a Smartphone-Fluidic Digital Imaging Analysis (SFDIA) System, which incorporates microfluidic techniques and Python-based video processing software, was developed for islet mass assessment. We quantified islets by tracking multiple moving islets in a microfluidic channel using the SFDIA system, and we achieved a relatively consistent result. The counts from the SFDIA and manual counting showed an average difference of 2.91 ± 1.50%. Furthermore, our software can analyze and extract key human islet mass parameters, including quantity, size, volume, IEq, morphology, and purity, which are not fully obtainable from traditional manual counting methods. Using SFDIA on a representative islet sample, we measured an average diameter of 99.88 ± 53.91 µm, an average circularity of 0.591 ± 0.133, and an average solidity of 0.853 ± 0.107. Via analysis of dithizone-stained islets using SFDIA, we found that a higher islet tissue percentage is associated with top-layer islets as opposed to middle-layer islets (0.735 ± 0.213 and 0.576 ± 0.223, respectively). Our results indicate that the SFDIA system can potentially be used as a multi-parameter islet mass assay that is superior in accuracy and consistency, when compared to conventional manual techniques.

The mitochondrial genome of Teratoscincus roborowskii (Squamata: Gekkonidae) (GenBank No. MT107158) was a circular molecule of 16,693 bp in length, including 13 protein-coding genes, 2 ribosomal RN...

The genetic structure and evolutionary relationship of Dulong chicken with other native Chinese species remained unclear. In this study, the mitochondrial control region was analyzed in total of 343 samples comprising 59 from Dulong chicken and 284 from 8 other Chinese local breeds revealed 51 mutation sites that defined 42 haplotypes. The maximum genetic variation was observed between the Shimian caoke and Pengxian yellow chickens. Phylogenetic analysis revealed that these local chickens mainly scatter in two southwestern clades. Dulong chickens have close relationship with other native chicken. Finding of this study suggests a single matrilineal lineage of indigenous Dulong chickens.

A metal-insulator-semiconductor (MIS) photosystem based on covalent organic framework (COF) semiconductors was designed for robust and efficient hydrogen evolution under visible-light irradiation. A maximal H2 evolution rate of 8.42 mmol h-1 g-1 and a turnover frequency of 789.5 h-1 were achieved by using a MIS photosystem prepared by electrostatic self-assembly of polyvinylpyrrolidone (PVP) insulator-capped Pt nanoparticles (NPs) with the hydrophilic imine-linked TP-COFs having =C=O-H-N= hydrogen-bonding groups. The hot π-electrons in the photoexcited n-type TP-COF semiconductors can be efficiently extracted and tunneled to Pt NPs across an ultrathin PVP insulating layer to reduce protons to H2 . Compared to the Schottky-type counterparts, the COF-based MIS photosystems give a 32-fold-enhanced carrier efficiency, attributed to the combined enhancement of photoexcitation rate, charge separation, and oxidation rate of holes accumulated in the valence band of the TP-COF semiconductor.

The experimental study on thermocapillary convection in liquid bridges of large Prandtl number has been carried out on Tiangong-2 in space. The purpose of these experiments is to study the oscillation instability of thermocapillary convection, and to discover and recognize the mechanism of destabilization of thermocapillary convection in the microgravity environment in space. In this paper, the geometry of a half-floating-zone liquid bridge is featured by the aspect ratio Ar and volume ratio Vr, and its influence on critical conditions of oscillatory thermocapillary convection is studied. More than 700 sets of space experiments have been finished. The critical conditions and oscillation characteristics of thermocapillary convection instability in the Ar–Vr parameter space have been fully obtained under microgravity conditions for the first time. It is found that the Ar–Vr parameter space can be divided into two regions of different critical conditions and oscillation characteristics: the region of low frequency oscillation, and the region of high frequency oscillation. More importantly, we obtain the complete configuration of these two stability neutral curves, and find that the low frequency mode is a ‘’ type curve. Based on this, we discuss the influence of heating rate on the oscillation mode. It is found that the heating rate affects the selection of critical mode, which results in a jump change of critical temperature difference. The findings of this study are helpful to better understand the critical modes and transition processes of thermocapillary convection in liquid bridges with different configurations.

Ethanol is a green, sustainable, and high-energy-density liquid fuel that holds great promise for direct liquid fuel cells (DLFCs). However, it remains highly challenging to develop electrocatalyst...

Acetophenones with a variety of substituents could be converted to diacylfuroxans in a solvent-free reaction by combining the reagents Fe(NO3)3·9H2O and P2O5 under high-speed ball milling. This reaction was facile and eco-friendly, and exhibits advantages in terms of better toleration, safety, and easier operation. The nitrate acid and nitrogen dioxide generated in situ should play a major role in this mechanochemical reaction.

Chemically functionalized carbon nanotubes were combined with PVC to enhance both toughness and strength by simply mixing long alkyl chain modified multi-wall carbon nanotubes (abbreviated as MWNTs) or Ester-functionalized soluble MWNTs (abbreviated as eMWNTs) with PVC in Tetrahydrofuran (THF)/Cyclohexanone (CH) solution to obtain good dispersity solution. The MWNTs modified with 1-Bromohexadecane can effectively increase the intermolecular force with PVC by hydrogen bond. The obtained nanocomposite has a regular shape with homogeneously dispersed particles. PVC/2 wt% eMWNTs has been proved to possess excellent thermal stability. The intermolecular force between eMWNTs and PVC endows the as-fabricated nanocomposite with enhanced toughness and strength, indicating that our method is promising for wide use in PVC/eMWNTs nanocomposition.

Influences of adverse pressure gradient (APG) on supersonic turbulent boundary layers are numerically studied using Reynolds-averaged Navier–Stokes (RANS) equations. The RANS methodology is validated by comparing the numerical results with the existing experimental data. Although the flame is restricted in the boundary layer, the heat flux is reduced rather than increased for the suppressed turbulence momentum transportation ability. Moreover, APG contributes more to the heat flux than combustion heat release does. Compared with no-injection case, a large skin friction reduction can be obtained by boundary layer combustion, and further reduction can be achieved in APG state. Additionally, the effects of combustion in APG on the velocity laws of the wall show that White's velocity law is close to the numerical results in the outer region of boundary layer, and Nichols's velocity law is appropriate in the whole boundary layer unless the APG is too strong. Turbulence intensity influences are analyzed in the end. Results show that the additional reduction of skin friction due to induced combustion cannot offset the skin friction increase caused by high turbulence intensity.

Particulate organic carbon (POC) produced in the surface ocean sinks through the water column and is respired at depth, acting as a primary vector sequestering carbon in the abyssal ocean. Atmospheric carbon dioxide levels are sensitive to the length (depth) scale over which respiration converts POC back to inorganic carbon, because shallower waters exchange with the atmosphere more rapidly than deeper ones. However, estimates of this carbon regeneration length scale and its spatiotemporal variability are limited, hindering the ability to characterize its sensitivity to environmental conditions. Here, we present a zonal section of POC fluxes at high vertical and spatial resolution from the GEOTRACES GP16 transect in the eastern tropical South Pacific, based on normalization to the radiogenic thorium isotope (230)Th. We find shallower carbon regeneration length scales than previous estimates for the oligotrophic South Pacific gyre, indicating less efficient carbon transfer to the deep ocean. Carbon regeneration is strongly inhibited within suboxic waters near the Peru coast. Canonical Martin curve power laws inadequately capture POC flux profiles at suboxic stations. We instead fit these profiles using an exponential function with flux preserved at depth, finding shallow regeneration but high POC sequestration below 1,000 m. Both regeneration length scales and POC flux at depth closely track the depths at which oxygen concentrations approach zero. Our findings imply that climate warming will result in reduced ocean carbon storage due to expanding oligotrophic gyres, but opposing effects on ocean carbon storage from expanding suboxic waters will require modeling and future work to disentangle.

We classify all the indecomposable modules of dimension ⩽ 5 over the quantum exterior algebra k〈x, y〉/〈x2, y2, xy + qyx〉 in two variables, and all the indecomposable modules of dimension ⩽ 3 over the quantum complete intersection k〈x, y〉/〈xm, yn, xy + qyx〉 in two variables, where m or n ⩾ 3; by giving explicitly their diagram presentations.

Financial returns of forest plantations are an important concern around the world. In this research, we focused on South China’s timber investments, collected data from the Pingxiang, Guangxi Province, China, which is the demonstration zone of Fast-growing and High-yielding Timber Plantation Base Construction Program and National Timber Strategic Storage and Production Bases Construction Program, and used capital budgeting analysis method and sensitivity analysis to compare different scenarios of planted forest management. The results showed that excluding land costs, (1) the financial returns of Eucalyptus forest managed by small business were excellent, having an IRR of 28% per year and a LEV of $7555 per ha, but it had a high risk with fluctuations of cost, timber price and timber yield; (2) the results for the Experimental Center of Tropical Forests indicate that the Eucalyptus forest and Castanopsis hystrix forest returns were greater than those for Cunninghamia lanceolata forest and Pinus massoniana forest, with having IRRs of 24%, 21%, 13% and 10% per year respectively. The mixed planted forest of Castanopsis hystrix × Eucalyptus and Castanopsis hystrix × Pinus massoniana had the features of high profits and low risks; (3) the forest farmers had lower levels of returns for Eucalyptus forest management in South China, but were still in the middle rank of global comparisons. This study gave a view of China’s timber investment and provided more options of improving the economic returns of planted forest management to both small businesses and forest farmers in South China.

A new analytical method is described for the colorimetric detection of sulfide. This approach involves the use of Pd nanocubes (PdNCs) as artificial peroxidases that can effectively generate a colored signal by catalyzing the oxidation of peroxidase substrates. In the presence of sulfide, the colored signal is greatly diminished because of the specific and efficient inhibition of the peroxidase-like activity of the PdNCs through their surface inactivation by the formation of PdS. Based on this finding, sulfide assay can be achieved in the 0.125–2.75 μM concentration range with a detection limit of 80 nM. This method shows high selectivity to sulfide besides other ions, and has been applied for the determination of sulfide in spiked real samples. It also features simplicity and rapidness since the assay can be conducted at room temperature, in aqueous solution, and requires only ∼5 min.

In this paper, one-step preparation of graphene/gold nanoparticle hydrogel film through the hydrothermal method is reported. The hydrogel film could be formed on a glass substrate under hydrothermal conditions, and upon freeze-drying, the aerogel film of 40 μm thickness with satisfying flexibility and strength is obtained. The aerogel composite film is characterized by scanning/transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy. Moreover, the aerogel film is directly used as the electrochemical electrode for sensing H2O2, and exhibits good performance with a broad linear range, low detection limit and excellent selectivity. This work provides a route for the fabrication of graphene film material with wide potential in various aspects.

The optical absorption properties of carbon nanotubes (CNTs) have attracted extensive research attention. Here we report the fabrication of sea-island structured polymer-based multi-walled CNT (MWNT) composite with high solar-thermal-conversion performance. MWNT-grafted 4-chloromethyl styrene (MWNTs-g-CMS) is prepared via esterification between carboxyl groups on the MWNT surface and the chloromethyl group of the CMS in the presence of a phase-transfer reagent in water. Covalent bonding between the CMS and the MWNTs is confirmed by Fourier transform infrared spectra. Thermogravimetric analysis of the MWNTs-g-CMS shows a mass percentage of the attached methyl styrene chains as high as 24.31 wt%. Subsequently, polymer-based MWNT-graft-polyvinyl-chloride (MWNTs-g-PVC) composite was prepared via an in-situ graft polymerization between the vinyl chloride and active styryl groups of the MWNTs-g-CMS. The MWNT grafting efficiencies in a series of MWNTs-g-PVC composites are 0.013–0.103%. The sea-island structure of the MWNTs-g-PVC composites and the fine dispersion of MWNTs in the island are verified by electron microscopy. The solar-thermal conversion performance of the MWNTs-g-PVC composites is studied. The composites exhibit excellent light-absorption properties that resemble a black body, and yield a higher solar-thermal conversion efficiency than the carboxylic MWNT (PVC/MWNTs-COOH) composites, which is attributed to the sea-island structure and the good dispersion of MWNTs in the islands.

Demands on effective diagnosis and therapy, especially in the antibacterial field, are increasing. This study presents multifunctional Fe3O4@NaGdF4:Yb:Er-HMME (Fe@UCNP-HMME) nanoparticles for applications in bioimaging as well as photodynamic therapy (PDT)/sonodynamic therapy (SDT). We constructed a core-shell structure of Fe3O4 and upconversion nanoparticles (UCNPs) for T2-weighted MRI and upconversion luminescence (UCL) imaging both in vitro and in vivo. Moreover, we modified the surface of the Fe@UCNPs with the photo/sonosensitizer hematoporphyrin monomethyl ether (HMME), which could be excited to produce 1O2 for photo/sonodynamic antimicrobial chemotherapy (PACT). Furthermore, deep tissue penetration of UCL and ultrasound led to the temporal induction of cytotoxicity when applied to drug-resistant Gram(+) and Gram(−) bacteria, by which these pathogens were efficiently killed through damage of the cell wall structure. In summary, we developed a multifunctional Fe@UCNP-HMME-based platform for both dual-modality imaging and photo/sonodynamic antimicrobial chemotherapy, employing its complementary array of UCL, T2-MRI, and 1O2 production properties to kill bacteria (100%) through PDT and SDT. Our experimental results verify the excellent potential of Fe@UCNP-HMME for applications in diagnosis and therapy.

Peroxidase-like activity of MoS2quantum dots can be manipulated by aggregation/dispersion in the presence of Fe3+or a mix of Fe3+and pyrophosphate (PPi). Based on this finding, a simple and reliable method for colorimetric PPi detection is developed.

In this work, we report a fast and colorimetric method for the detection of antioxidants based on the oxidase-like activity of two-dimensional MnO2 nanosheets. Specifically, MnO2 nanosheets can transform the colourless substrate, 3,3',5,5'-tetramethylbenzidine (TMB), into a deep blue product (oxTMB) via catalytic oxidation, with a specific absorption peak arising at 652 nm. In the presence of antioxidants, both the dramatic colour fading and the decrease in absorbance at 652 nm are observed owing to the inhibition of catalytic oxidation of TMB, where MnO2 nanosheets can be transformed into Mn2+ with the aid of antioxidants. Based on the linear relationship between the absorbance at 652 nm and the concentration of the antioxidants, quantitative determination of antioxidants in the range of 0.1-12 μM has been achieved. Moreover, combined with smartphone-based technology, a portable colorimetric analytical platform for assay of antioxidants is further developed. This method shows advantages including easy operation, low cost, rapid detection and high sensitivity and has been successfully applied in the determination of total antioxidants in red wine.

We establish the weighted estimates for the parametric Marcinkiewicz integral operators with rough kernels along “polynomial curves” on $$\mathbb {R}^n$$ . As applications, we obtain that the above operators are bounded on the mixed radial-angular spaces, on the vector-valued mixed radial-angular spaces and on the vector-valued function spaces. Particularly, the above bounds are independent of the coefficients of the polynomials in the definition of the operators.

At present, China's carbon emissions rank first in the world, which not only brings huge challenges to the sustainable development of China's economy, but also brings more pressure from public opinion in the international community. With the outward migration of China's manufacturing industries to Southeast Asia, the carbon emissions embodied in trade has also been transferred. These trends provide a good opportunity to analyze the characteristics of transnational industrial restructuring and spatial structure transformation of carbon emissions between China and Southeast Asian countries. In 2020, ASEAN has become China's largest trading partner, and Thailand, due to its unique industrial structure and investment environment, will surely become one of the main ASEAN countries to undertake the transfer of China's manufacturing industry. Over the years, the shift of carbon emissions by the continuous transfer of a large number of basic manufacturing industries from China to Thailand promoted the release of China's carbon emission pressure. In this article, on the basis of the data of import and export commodities between China and Thailand from 2012 to 2017, the input-output model is carried out to analyze the energy consumption of China's various industries, and three periods, namely 2012, 2015, and 2017, are used to be key periods to calculate the embodied carbon of China's manufacturing migration and Sino-Thailand trade. The empirical results show that the transfer of China's manufacturing to Thailand from 2012 to 2017 has continued to rise. The transfer of Chinese manufacturing to Thailand is positively correlated with the carbon emissions of trade between the two countries, which has promoted the relief of China's pressure on energy conservation and emission reduction. Therefore, government departments should formulate differentiated and stable domestic manufacturing policies, spend on the development of advanced manufacturing industries with low energy consumption and high technology density, and encourage the relocation of industries with low technology density and high-carbon emissions to effectively reduce environmental pressure in China.

The synthesis of stimuli-responsive hybrid structures composed of drug-loaded UiO-66 metal-organic framework nanoparticles, NMOFs, locked by DNA tetrahedra gates is presented. The hybrid systems combine the high loading capacity of drugs in the porous NMOFs and the effective cell permeation properties of the DNA tetrahedra. The nucleic acid-functionalized UiO-66 NMOFs are loaded with drugs (doxorubicin, DOX, or camptothecin, CPT) or with dyes as drug models (Rhodamine 6G or fluorescein) and used to prepare stimuli-responsive carriers. In this study, two different stimuli-responsive NMOFs are presented. One system introduces the drug-loaded NMOFs locked by pH-responsive DNA tetrahedra. At acidic pH values, the gating tetrahedra are dissociated from the NMOFs through the formation of i-motif structures, resulting in the unlocking of the NMOFs and the release of the drugs. In addition, the tetrahedra gates are modified with AS1411 aptamer tethers, and these target the drug-loaded NMOFs to nucleolin receptors overexpressed in certain malignant cells. A second system involves the preparation of NMOFs loaded with drugs/dyes and gated by the microRNA (miRNA)-responsive tetrahedra (miRNA-21 or miRNA-155). In the presence of miRNAs, the dissociation of miRNA-responsive tetrahedra from the NMOFs leads to the unlocking of the NMOFs and the release of the loads. Further developments of the miRNA-responsive tetrahedra-gated hybrid carriers include the following. (i) By appropriate engineering of the miRNA gating units, the exonuclease III (Exo III)-amplified unlocking of the carriers, through the regeneration of the miRNA triggers, and the enhanced release of the loaded drugs are demonstrated. (ii) By applying mixtures of miRNA-21-responsive DNA tetrahedra-gated DOX-loaded NMOFs and miRNA-155-responsive DNA tetrahedra-gated CPT-loaded NMOFs, the multiplexed miRNA-21/miRNA-155-dictated release of the drugs is demonstrated. As compared to the analog DNA duplex-modified NMOFs, DNA tetrahedra-gated, drug-loaded NMOFs permeation into malignant MDA-MB-231 breast cancer cells presents more effective cell permeation. Effective and selective cytotoxicity toward the malignant cells, as compared to nonmalignant epithelial MCF-10A breast cells, is demonstrated due to the acidic pH, present in cancer cells, or the miRNA-21, present in MDA-MB-231 malignant cells.

The blast furnace casthouse is a typical heavy-polluting factory building of a steel enterprise. During the tapping process and the taphole opening, the dust concentration in the factory building's workroom can reach tens of thousands mg/m³. Over time, the air pollutants in the workplace can have unwanted consequences on employees' health. This paper selected a typical blast furnace tapping workshop and measured on-site the characteristics of the wind speed distribution, temperature distribution, and soot concentration distribution during the taping period. A numerical simulation model was established to analyze the taphole smoke exhaust system's performance based on computational fluid dynamics. The findings are: the velocity, temperature, and smoke density distributions in the workplace were very uneven, and the thermal comfort of the workers' area was relatively poor. Also, the concentration of PM2.5 was mostly below 80μg/m³. Besides, due to the plant's on-site measurement, real data was obtained for numerical simulation verification, making the evaluation of the entire plant's ventilation performance more reliable. Hence, this article's finding provides a scientific basis for optimizing the air distribution in the blast furnace cast house's workplace.

The development of space experiment payload for studying thermocapillary convection in the liquid bridge with large Pr number on TG-2 space laboratory as well as the experiments are presented in detail in this paper, and the objectives of the space experiments are confirmed. The functions of the payload are analyzed, and the technical and engineering specifications are determined. Detailed designs and experimental verifications are performed on the structure of liquid bridge columns, the method of bubble removing in the liquid, the bridge cleaning system, the accurate control of aspect ratio and volume ratio, and the high-sensitivity measurement of fluid temperature. Matching experiments on the ground according to space experiment properties are carried out, 5cSt silicone oil is selected as the fluid medium in space experiments. And the states of liquid bridge and temperature oscillation signals obtained from space experiments are presented at the end of this paper. Specific summarizations and discussions to the experiment project on fluid science in space are conducted in this paper, which will provide a useful reference for scientists participating space experimental research in the future.

The hysteresis of water-sediment mixture seepage in rock fractures is one of the critical factors which affect the determination of the timing of coal mine water inrush disasters prevention and control. In this paper, a mechanical model was established to study the hysteresis whose criteria were also put forward. The area of the hysteresis loop and the maximum pressure gradient were selected as characterization parameters of hysteresis. On this basis, an experimental system was established to study influences of different sand particle size, sand mass concentration, and fracture opening on water-sediment mixture seepage in rock fractures. The results indicated that the increase in the sand particle size and sand mass concentration could effectively enhance hysteresis characteristics of specimen fractures. While hysteresis characteristics decreased significantly with the increase of fracture opening. The research results are useful to prevent and control water inrush disasters of coal mine.

We investigate the spatial Goos-Hanchen (GH) shift of reflected beam from quasicrystals composed of Fibonacci dielectrics and graphene. The quasicrystals are composed of two symmetrical Fibonacci dielectrics and graphene is embedded in the center of the quasicrystals. The compound structure could induce enhanced band edge states, around which the complex phases of reflection coefficients change dramatically with the light wavelength. Consequently, large spatial GH shifts which may be negative and positive are achieved. Furthermore, the signs of GH shifts may be tuned by the incident wavelength conveniently. This may have potential applications for highly sensitive sensors.

Quinolones are ranked as the second most commonly used class of antibiotics in China, despite their adverse clinical and environmental effects. However, information on their cardiac developmental toxicity to zebrafish is limited. This study investigates the relationships between different quinolone structures and toxicity in zebrafish embryos using in vivo and in silico methods. All of the experimentally tested quinolones show cardiac developmental toxicity potential and present mortality and teratogenic effects in a dose-dependent manner. Theoretically, the acute toxicity values predicted using quantitative structure−toxicity relationship (QSTR) modeling based on previously reported LC50 values are in good agreement with the in vivo results. Further investigation demonstrates that the hormetic concentration response of some quinolones may be related to methylation on the piperazine ring at the C-7 position. The amino group at the C-5 position, the methylated or ethylated piperazine group at the C-7 position, halogens at the C-8 position and a cyclopropyl ring at N1 position may be responsible for cardiac developmental toxicity. In terms of survival (key ecological endpoint), the naridine ring is more toxic than the quinoline ring. This combined approach can predict the acute and cardiac developmental toxicity of other quinolones and impurities.

Carotid atherosclerosis is the leading cause of death worldwide. Magnetic Resonance Imaging (MRI) techniques are commonly used to depict luminal stenosis resulting from atherosclerosis progression. This paper proposed a yolov3 based method to automatically detect carotid arteries in MRI images, which includes two branches: coordinate prediction and confidence prediction. The network also use the K-means clustering to get nine sizes of bounding box priors. Compared with other methods, this network has high accuracy and processing speed and can realize the automatic detection of carotid arteries, which greatly reduces the burden on doctors.

In this paper, the iterated commutators of multilinear maximal square function and pointwise multiplication with functions in Lipschitz spaces are studied. Some new estimates for the iterated commutators with kernels satisfying some Dini type conditions on Lebesgue spaces, homogenous Lipschitz spaces and homogenous Triebel-Lizorkin spaces will be given, respectively.

Regulating the catalytic activity of nanozymes is significant for their applications in various fields. Here, we demonstrate a new strategy to achieve reversible regulation of the nanozyme’s activity for sensing purpose. This strategy involves the use of zero-dimensional MoS2 quantum dots (MQDs) as the building blocks of nanozymes which display very weak peroxidase (POD)-like activity. Interestingly, such POD-like activity of the MQDs largely enhances in the presence of Fe3+ while diminishes with the addition of captopril thereafter. Further investigations identify the mechanism of Fe3+-mediated aggregation-induced enhancement of the POD-like activity and the inhibitory effect of captopril on the enhancement, which is highly dependent on their concentrations. Based on this finding, a colorimetric method for the detection of captopril is developed. This sensing approach exhibits the merits of simplicity, rapidness, reliability and low cost, which has been successfully applied in quality control of captopril in pharmaceutical products. Moreover, the present sensing platform allows smartphone read-out, which is promising to apply in point-of-care testing devices for clinical diagnosis and drug analysis.