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Side-chain alkylation of toluene with methanol is a green pathway to realize the one-step production of styrene under mild conditions, but the low selectivity of styrene is difficult to be improved with by-products of ethylbenzene and xylene. In this study, a new way is introduced to improve the catalytic performance by means of assisting basic compounds as co-catalysts during the toluene side-chain alkylation with methanol to styrene. As a result, high activity of side-chain alkylation appears over the basic Cs-modified zeolite catalysts prepared by ion exchange and impregnation methods. This high performance should be mainly attributed to two co-catalysis actions: (1) the promotion of basic compounds for methanol dehydrogenation to formaldehyde as the intermediate for side-chain alkylation; (2) the suppression of the styrene transfer hydrogenation on basic Cs-modified zeolites to avoid the formation of ethylbenzene. Especially for Cs2O/CsX-ex catalyst, the addition of 2 mol% 2-picoline in reaction mixture could achieve both 12.3% toluene conversion and 84.1% styrene selectivity. Whereas the higher concentration of 2-picoline (>6 mol%) caused an inhibition to the catalytic activity because the excessive basic compound poisoned the combined acid-base pathway required for the side-chain alkylation process. In addition, two possible side-chain alkylation reaction routes on Cs-modified zeolite under the different 2-picoline absorption were described.

Excellent radiation resistance is a prerequisite for pressure-sensitive hydrogels to be used in high-energy radiation environments. In this work, tannic acid-modified boron nitride nanosheet (BNNS-TA) is first prepared as the radiation-resistant additive by a facile one-step ball milling of hexagonal boron nitride and tannic acid. Then, polyacrylamide (PAAm)-based pressure-sensitive hydrogel doped with BNNS-TA and Fe3+ ions is fabricated. The ternary BNNS-TA/Fe3+/PAAm hydrogel exhibits excellent compressive strength (at least four times the compressive strength of unfilled pure PAAm hydrogel), pressure-sensitive performance (gauge factor is up to 1.4), and performance recovery due to the combination of multiple intermolecular interactions, such as covalent crosslinking, hydrogen bonds, and ion coordination interactions. The BNNS-TA/Fe3+/PAAm hydrogel can be made as a pressure sensor installed in the control circuit or attached on the human body to detect human activities accurately. More importantly, the compressive strength and the pressure-sensitive performance of the BNNS-TA/Fe3+/PAAm hydrogel can be maintained after the hydrogel is irradiated by 60Co gamma-ray at an absorbed dose of 15 kGy. As a comparison, the compressive strength of the unfilled PAAm hydrogel is only a quarter of that before irradiation. This work not only reveals a facile method to achieve the preparation of chemically modified BNNS as a promising radiation-resistant additive but also provides a novel strategy for the development of pressure-sensitive hydrogel devices in radiation environments.

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a polarization of $\sim$80%) and protons (with a polarization of $\sim$70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2-3) $\times$ 10$^{33}$ cm$^{-2}$ s$^{-1}$. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC. The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies. This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China., EicC white paper, written by the whole EicC working group

In the single-point diamond turning (SPDT) of optical spherical/aspheric surface, tool deviating from the spindle rotation center significantly deteriorates the form accuracy of the spherical/aspherical surface and its optical performance. In this study, the influence of tool deviation on the form accuracy of a convex spherical surface and the cutting force forms during the turning process were studied first, following which a force-based tool deviation model was derived to identify the tool deviation using cutting force. Finally, by analyzing the influence of tool deviation on the three-dimensional (3D) form of residual structures at the center of the convex spherical surface, the 3D form of the convex spherical surface was predicted online. Results indicate the existence of a mapping relation between the tool deviation and the cutting force form, which could be further used to online predict the 3D form of the machined convex spherical surface in SPDT through the established geometric model.

As a novel method to reduce the temperature during electron beam welding, and to subsequently inhibit interfacial reaction between SiC and Al matrix, the electron beam surface heating - diffusion bonding is proposed for joining SiC particle reinforced aluminum alloy metal - matrix composite of 45 vol.% SiC/2024 Al. The defocused electron beam was used to heat the base metal surface, and the simultaneous pressure was applied to the butt surface to achieve bonding. The base metals were successfully joined by diffusion. The maximum temperature of the whole joint was effectively decreased to less than 650 ℃. The Gibbs free energy change of interfacial reaction was calculated, meaning a positive value reaching 218 kJ/mol and a consequently prominent inhibitory effect on the formation of brittle Al4C3 that was proved by microstructural observation. The tensile strength for the bonded joint was increased by 35 % compared to that for ordinary welded joint. When the TC4 layer was added, TiC strengthening particles were formed with the deficiency of Al4C3, corresponding to the significantly increased tensile strength of 63 % of base metal (154 MPa).

Blackleg of oilseed rape is a damaging invasive disease caused by the species complex Leptosphaeria maculans (Lm)/L. biglobosa (Lb), which is composed of at least two and seven phylogenetic subclades, respectively. Generally, Lm is more virulent than Lb, but under certain conditions, Lb can cause a significant yield loss in oilseed rape. Lb ‘brassicae’ (Lbb) has been found to be the causal agent for blackleg of oilseed rape in China, whereas Lm and Lb ‘canadensis’ (Lbc) were frequently detected in imported seeds of oilseed rape, posing a risk of spread into China. To monitor the blackleg-pathogen populations, a diagnostic tool based on loop-mediated isothermal amplification (LAMP) was developed using a 615-bp–long DNA sequence from Lbb that was derived from a randomly amplified polymorphic DNA assay. The LAMP was optimized for temperature and time, and tested for specificity and sensitivity using the DNA extracted from Lbb, Lbc, Lm, and 10 other fungi. The results showed that the optimal temperature and time were 65°C and 40 min, respectively. The LAMP primer set was specific to Lbb and highly sensitive as it detected the Lbb DNA as low as 132 fg per reaction. The LAMP assay was validated using the DNA extracted from mycelia and conidia of a well-characterized Lbb isolate, and its utility was evaluated using the DNA extracted from leaves, stems, pods, and seeds of oilseed rape. The LAMP assay developed herein will help for monitoring populations of the blackleg pathogens in China and in developing strategies for management of the blackleg disease.

Liaodong oak (Quercus liaotungensis Koidz.) dominated forests contribute to the few natural forest ecosystems in the semiarid Loess Plateau region in China. This study investigated the influence of soil nutrients and stand structure on aboveground net primary productivity (ANPP) in the oak communities. We aimed to understand the major factors and their possible pathways that determine the ecosystem productivity. The biomass and the ANPP were estimated using plot surveys and litterfall collection in fixed plots. Linear regressions and structural equation models were used to evaluate the relationships among soil nutrients, stand structure (including vertical and horizontal structure), and ANPP. The results showed that the effect sizes of soil nutrients on ANPP and leaf production were near 60% and 70%, respectively. More than 70% of the variation in woody production was explained by stand structure, while litterfall production was largely dependent on stand vertical structure with effect size of 64%. The effect of soil nutrients on stand structural indices was detected only in the case of the vertical structure. The results suggested that soil nutrients could affect forest productivity both directly and indirectly in coordination with stand vertical structure, and that the effect of stand structure was limited in these communities.

The Al–Al2O3 composites were prepared by fused alumina, α-Al2O3 micropowders, and metal aluminum powder. The samples with 3% carbon black (N330), 3% resin powder and α-Al2O3 micropowder, 10% α-Al2O3 micropowder were named S1, S2, and S3, respectively. They were oxidized at 1500 °C for 3 h in a box-type electric furnace, and then the unoxidized areas were analyzed by X-ray diffraction and scanning electron microscopy. It was found that the aluminum oxycarbonitride formed in situ during the oxidation resistance test inhibited further oxidation of S2. The in situ formation mechanism of aluminum oxycarbonitride in the unoxidized zone is believed to be 7Al + 3Al3C4 + 12AlN + 4Al2O3 = 12Al3CON, which is also verified and proven by XRD, SEM and EDS in this work. The oxidation depth of S2 is 46.7% lower than that of S3. Sample S2 hardly has any linear change after fired at 1500 °C × 3 h in coke, which benefits to improve the volume stability and prolongs the service life. Among the three batches, S2 exhibits the minimum creep rate, from 0% to 0.026% at 1500 °C, and the HMOR at 1500 °C in a N2 atmosphere of S2 is 58 MPa. The Al–Al2O3 composites combined with resin strengthened by in situ formed aluminum oxycarbonitride give the composites excellent high-temperature strength owing to the fiber-intersected reinforced microstructure of Al3CON crystals at high temperature. In the Al–C–N–O system, it was found that the general formula of aluminum oxycarbonitride is expressed by Al4n+m(C,O,N)3n+m, and the (n, m) values are (0, 3) for Al3CON.

Fly ash has been widely explored in alkali-activated concrete technology as a precursor; however, it suffers sudden brittle failure and requires heat activation for early-strength development. Previous studies have demonstrated that these shortcomings can be overcome by adding nanosilica and various types of fibers. However, they were mainly focused on improving the mechanical properties, but there is no clear understanding of the durability and microstructural changes. Therefore, this study systematically addresses the effects of nanosilica sol and hybrid fibers (steel and polypropylene fibers) on the workability, porosity, flexural/compressive strength development, flexural toughness, crack resistance, and durability (subjected to sulfuric acid of pH = 1, 5% sodium sulfate, and 3.5% seawater attacks) of fly ash-based mortars cured at ambient environments. The results demonstrate that nanosilica and hybrid fibers have acceptable simultaneous effects on the properties of mortar. Although they both reduce fluidity, nanosilica improves the pore enlargement caused by fiber materials; thus, it greatly improves the mechanical properties of mortar. The flexural toughness of the mortar with nanosilica and hybrid fibers was approximately 200% higher than that of the pure-fly ash. Only approximately 58.25 mm2 microcracks were observed during the early crack detection, and the residual strength also improved under chemical solution attack. The microstructures were studied by field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray diffraction/Rietveld method, and nanoscale 3D X-ray microscopy. The nanosilica enhanced the reactivity of the precursors and refined the pore structure of the mortar due to the changes in the crystalline and amorphous phases, and the hybrid fibers produced composites with good internal characteristics and strong fiber/matrix interfacial bonding.

The Meso-Neoproterozoic Rodinia supercontinent formed a coherent large landmass, which was later dispersed over all current major continents and a number of microcontinents. The Qinling block is a Precambrian continental mass, located in the Qinling orogenic belt, which marks the junction of the North China and South China cratons. In this paper, we present a systematic study of the petrology, whole-rock geochemistry and geochronology of metasedimentary rocks from the Xiahe Group, which is a key unit of the Precambrian basement in the Qinling block, to constrain the paleogeographic reconstruction of Rodinia. The studied metasedimentary rocks have detrital zircon ages of 3054–1082 Ma that peak at 1172 Ma and 1582 Ma. The protoliths of the metasedimentary rocks are mainly shales and wackes with maximum depositional ages from 1147 to 1082 Ma, representing a part of a continental arc-related sedimentary sequence. Combining our results with existing data, we propose that their protoliths constituted a sedimentary series including an older sequence of basement and a younger sequence with depositional ages between 1262 and 840 Ma. The detritus that is older than 1266 Ma was sourced from the continental margin of the Indian craton, which was part of the Columbia supercontinent. There was a Paleo-Mesoproterozoic continental nucleus in the Qinling block that split from the margin of the Indian craton during the breakup of Columbia. The source rocks for the younger detritus were arc magmatic rocks in the Qinling block, which formed in a continental arc by oceanic lithosphere subduction during the assembly of Rodinia. A sequence of oceanic subduction beneath the continental nucleus of the Qinling block (1262–981 Ma), arc-continent collision between the continental nucleus and the Indian craton (981–911 Ma), continuous subduction of oceanic crust beneath the block with formation of a mature volcanic arc (929–833 Ma), and continental rifting (833–774 Ma) during the formation of the Qinling block was identified. The block faced the Neoproterozoic ocean during the assembly of Rodinia, and finally rifted off the supercontinent during its breakup to form an isolated arc terrane

To analyze the influence of a curved ceiling and fire location on the combustion characteristics in a utility tunnel, the burning rate and temperature profile produced by a pool fire beneath a curved ceiling were investigated experimentally and theoretically. The results showed that oxygen supply and heat feedback from the surrounding form a competitive mechanism, determining the evolution of the burning rate. A qualitative analysis was performed to elucidate this competitive mechanism. With the fire source moving close to the sidewall, the positive influence from the heat feedback is is gradually compensated for by the negative influence from oxygen supply limitation. Moreover, it was inferred that the magnitude of decline of the burning rate near the wall has a positive correlation with heat release rate of the fire source. A characteristic inclined angle was defined to replace the changing angle of the curved ceiling along the ceiling jet path. Based on the definition of the characteristic ‘inclined angle’ concept, the relationship between the temperature profile beneath the curved ceiling centerline, tunnel height and horizontal position from fire source was unified by an empirical model. The maximum temperature delay beneath the curved ceiling centerline produced by the pool fire was analyzed by radial flow and one-dimensional flow. The proposed models for radial flow and one-dimensional flow were validated and could effectively predict the maximum temperature delay, which can be applied in utility tunnel’s fire protection engineering.

Hydratable magnesium carboxylate (HMC), which is similar to the properties of cement, can be used as a potential binder for refractory castables. However, its decomposition may lead to poor mechanical properties at medium temperatures (300 °C–1100 °C). This work investigated the effects of boric acid on the mechanical properties and microstructural evolution of castables bonded with hydratable magnesium carboxylate. The mechanical strength, bulk density, apparent porosity, thermal shock resistance, and sintering properties of the castables were evaluated. The results showed that the mechanical properties of HMC-bonded castables (HMCC) at various temperatures can be improved by adding boric acid. Boric acid reacts with HMC to form magnesium carboxylate borate ester (MCBE), which improves the bonding strength between HMC molecules. Thus, the cold modulus of rupture of HMCC containing boric acid dried at 110 °C are higher than that of calcium aluminate cement-bonded refractory castables (CACC). The decomposition temperature of MCBE is 77 °C higher than that of HMC, so MCBE can endow castables with better mechanical properties at 110 °C–500 °C. The B4C obtained by MCBE pyrolysis could form a boron-rich liquid phase, which can accelerate the structural densification of castables via transient liquid phase sintering, thus improving the mechanical properties of castables at 500 °C–1100 °C. Moreover, boric acid can improve the thermal shock resistance of HMCC. The residual strength rate first increases and then decreases with an increasing boric acid, and reaches a maximum value of 29.7% (1 wt% boric acid is added), which is 2.3 times that of the CACC. The nanoindentation test showed that the microcracks in the matrix of 1 wt% boric acid castables are easy to initiate but difficult to propagate, so the microcracks are many and wavy.

Since the production process in manufacturing industry is one of the main sources of carbon emissions, most governments have enacted relevant carbon policies to encourage manufacturers to invest in green production technology and reduce carbon emissions. However, the effectiveness of the carbon policy deserves further investigation because the manufacturers focus more on economic profits in actual operations. For this purpose, this paper proposes a dual-channel supply chain network (DCSCN) equilibrium model based on variational inequality theory to examine progressive carbon tax mechanism design of the government and its impacts on the production/pricing and abatement level decisions of the manufacturers in the DCSCN. In addition, this paper also examines the influences of the online channel introduction on supply chain network equilibrium decisions, carbon emissions and profits. We employ the modified projection and contraction algorithm to obtain the numerical solutions for several examples, and analyze the impacts of the key parameters on the equilibrium decisions and derive several managerial insights. The results show that if the government sets the high-level carbon tax and the cut-off value in progressive carbon tax policy appropriately, it can induce the manufacturers to improve abatement level actively; meanwhile the profit maximization goal of the manufacturer and the whole DCSCN can be consistent with the government's low-carbon emission target. Moreover, the introduction of online channel may depress the economic activities and lead to profit loss for the supply chain network but contributes to reducing the carbon emissions under progressive carbon tax policy. The conclusions may be useful for reference in the study of the low-carbon supply chain and the design of carbon emission reduction policy for government.

We performed a genome-wide scan to detect selection signatures that showed evidence of positive selection in the domestication process by re-sequencing the whole genomes of Landrace and Yorkshire pigs. Fifteen annotated elements with 13 associated genes were identified using the Z-transformed FST (Z(FST)) method, and 208 annotated elements with 140 associated genes were identified using the Z-transformed heterozygosity (ZHp) method. The functional analysis and the results of previous studies showed that most of the candidate genes were associated with basic metabolism, disease resistance, cellular processes, and biochemical signals, and several were related to body morphology and organs. They included PPP3CA, which plays an essential role in the transduction of intracellular Ca2+-mediated signals, and WWTR1, which plays a pivotal role in organ size control and tumor suppression. These results suggest that genes associated with body morphology were subject to selection pressure during domestication, whereas genes involved in basic metabolism and disease resistance were subject to selection during artificial breeding. Our findings provide new insights into the potential genetic variation of phenotypic diversity in different pig breeds and will help to better understand the selection effects of modern breeding in Landrace and Yorkshire pigs.

The complex mixed feeding process for the binary mixture of coal and cylindroid biomass particles in a screw feeder was numerically studied by the discrete element method (DEM). The effects of biomass feeding ratio, feeding rate, and screw rotational speed on the feeding performance were investigated with the continuity, uniformity, and stability of the mixed feeding process being emphatically discussed. The results reveal that the stability of real-time mass flow rate and biomass blending ratio performs better at higher biomass feeding ratios. A larger variability of real-time biomass blending ratio is found at low feeding rate, while increasing the feeding rate reduces the stability of real-time mass flow rate and the too high feeding rate would cause some cylindroid biomass particles being hindered by the front wall surface of the hopper. Moreover, increasing the screw rotational speed significantly increases the stability of the mixed feeding process.

A total of 707 isolates of Botrytis were collected from plastic tunnel-grown strawberry and tomato in the Hubei province of China. They were identified based on the specific molecular markers. Diversity of the B. cinerea (Bc) isolates was evaluated by typing the transposable elements (Boty, Flipper) and the mating types (MAT1-1, MAT1-2), as well as by determining virulence on tobacco (Nicotiana benthamiana) and fenhexamid sensitivity in agar medium. The results showed that 706 isolates (99.9%) were Bc and 1 isolate (0.1%) was B. pseudocinerea. The Bc isolates (n = 706) were classified into four transposable element types, Vacuma (3.1%), Boty (9.6%), Flipper (18.4%), and Transposa (68.8%). The strawberry and tomato subpopulations of Bc had significantly different (P < 0.05) compositions of the four transposable element types. The overall ratio of MAT1-1 to MAT1-2 deviated from 1:1 (n = 706; P = 0.0002), and MAT1-2 (56.9%) predominated over MAT1-1 (43.1%). In 7 of 12 geographic subpopulations, the ratio of MAT1-1 to MAT1-2 matched 1:1; however, in the remaining five geographic subpopulations, the ratio of MAT1-1 to MAT1-2 did not match 1:1. Results of the biological characterizations showed that most Bc isolates were highly sensitive or sensitive to fenhexamid, and the majority of Bc isolates were highly virulent or virulent on tobacco. Moreover, the relationship between genetic diversity and biological characteristics was analyzed. The results achieved during this study are helpful for understanding of the populations of B. cinerea.

Sulfur-doped carbon nanotubes (SCNTs) exhibit better conductivity and hydrophilicity, as compared to the undoped carbon nanotubes (CNTs). Low cost mass production of SCNTs is highly desirable for their real application at an industrial scale. Here, scalable green syntheses of SCNTs and S, N dual doped CNTs (SNCNTs) are demonstrated based on the gaseous S doping using SO2 as dopant. The process not only significantly promotes the hydrophilicity and conductivity of CNTs due to the incorporation of S atoms in carbon framework, but also purifies the final product due to burning off the carbon coatings of metal particles. SO2 is generated by CaSO3 pyrolysis and absorbed by CaO, thus realize the recycling of S species. The LiFePO4 cathodes using the as-prepared SCNTs and SNCNTs as conductive additive exhibit enhanced capacity and rate performance than the electrodes prepared with the pristine CNTs, not matter using N-methyl pyrrolidone or water as solvent.

Kondo effect is an interesting phenomenon in quantum many-body physics. Niobium (Nb) is a conventional superconductor important for many superconducting device applications. It was long thought that the Kondo effect cannot be observed in Nb because the magnetic moment of a magnetic impurity, e.g. iron (Fe), would have been quenched in Nb. Here we report an observation of the Kondo effect in a Nb thin film structure. We found that by co-annealing Nb films with Fe in Argon gas at above 400 $$^{\circ }$$ ∘ C for an hour, one can induce a Kondo effect in Nb. The Kondo effect is more pronounced at higher annealing temperature. The temperature dependence of the resistance suggests existence of remnant superconductivity at low temperatures even though the system never becomes superconducting. We find that the Hamann theory for the Kondo resistivity gives a satisfactory fitting to the result. The Hamann analysis gives a Kondo temperature for this Nb–Fe system at $$\sim $$ ∼ 16 K, well above the superconducting transition onset temperature 9 K of the starting Nb film, suggesting that the screening of the impurity spins is effective to allow Cooper pairs to form at low temperatures. We suggest that the mechanism by which the Fe impurities retain partially their magnetic moment is that they are located at the grain boundaries, not fully dissolved into the bcc lattice of Nb.

Tin dioxide (SnO2) has been demonstrated as one of the promising electron transport layers for high-efficiency perovskite solar cells (PSCs). However, scalable fabrication of SnO2 films with uniform coverage, desirable thickness and a low defect density in perovskite solar modules (PSMs) is still challenging. Here, we report preparation of high-quality large-area SnO2 films by chemical bath deposition (CBD) with the addition of KMnO4. The strong oxidizing nature of KMnO4 promotes the conversion from Sn(II) to Sn(VI), leading to reduced trap defects and a higher carrier mobility of SnO2. In addition, K ions diffuse into the perovskite film resulting in larger grain sizes, passivated grain boundaries, and reduced hysteresis of PSCs. Furthermore, Mn ion doping improves both the crystallinity and the phase stability of the perovskite film. Such a multifunctional interface engineering strategy enabled us to achieve a power conversion efficiency (PCE) of 21.70% with less hysteresis for lab-scale PSCs. Using this method, we also fabricated 5 × 5 and 10 × 10 cm2 PSMs, which showed PCEs of 15.62% and 11.80% (active area PCEs are 17.26% and 13.72%), respectively. For the encapsulated 5 × 5 cm2 PSM, we obtained a T80 operation lifetime (the lifespan during which the solar module PCE drops to 80% of its initial value) exceeding 1000 h in ambient condition.

In single-point diamond turning (SPDT), two-dimensional (2D) tool centre error is caused by the tool deviating from the workpiece rotation centre both in the horizontal direction (tool feed direction) and vertical direction (perpendicular to tool feed direction). This greatly affects the form accuracy of the machined surface and its optical function. Traditional tool centre error identification is usually performed off-machine manually with high-precision instruments, which is time-consuming and labour-dependent. In this paper, a novel force-based 2D tool centre error identification method in SPDT is introduced. First, according to the relative position between the tool and workpiece centre, the tool centre error is classified into nine cases. The relation between the cutting force profiles and the tool centre error is analysed for each case. Then, a numerical fitting model and a geometric model are established to identify tool-above-centre and tool-below-centre errors, respectively. Additionally, a geometric model is established to calculate the normal distance from the tool interference/exit cutting to the workpiece centre, which serves as a reference for the horizontal tool centre error identification. Finally, the on-machine identification results of the 2D tool centre error are verified by experiments. Theoretical and experimental results show that the proposed on-machine 2D tool centre error identification method is effective and accurate, which greatly improves the cutting efficiency in SPDT.

The addition of C/MgAl2O4 composite powders can improve the thermal shock resistance of low-carbon Al2O3–C refractories attribute to the formation of microcracks in the agglomerated structure, thus consuming more thermal stress and strain energy. Moreover, C/MgAl2O4 composite powders additive promote the formation of short fibrous ceramic phases in the refractories, which suggest a bridging role in the interior of the refractories and increase its toughness. Furthermore, the C/MgAl2O4 composite powders also result in a remarkable enhancement of the slag corrosion resistance in the refractories.

Manipulation of long-lived triplet excitons in organic molecules is key to applications including next-generation optoelectronics, background-free bioimaging, information encryption, and photodynamic therapy. However, for organic room-temperature phosphorescence (RTP), which stems from triplet excitons, it is still difficult to simultaneously achieve efficiency and lifetime enhancement on account of weak spin-orbit coupling and rapid nonradiative transitions, especially in the red and near-infrared region. Herein, we report that a series of fluorescent naphthalimides-which did not originally show observable phosphorescence in solution, as aggregates, in polymer films, or in any other tested host material, including heavy-atom matrices at cryogenic temperatures-can now efficiently produce ultralong RTP (ϕ=0.17, τ=243 ms) in phthalimide hosts. Notably, red RTP (λRTP =628 nm) is realized at a molar ratio of less than 10 parts per billion, demonstrating an unprecedentedly low guest-to-host ratio where efficient RTP can take place in molecular solids.

To understand rural sustainability, it is necessary to scrutinize the relationship between rural transition and economic growth. The article uses rural multifunctionality as an analytical lens through which to view the processes of the development of rural occupancy. There is a pressing need to ascertain how to quantify rural multifunctionality and reveal its spatial differentiation, as well as garner and investigate how multifunctional rural transition (MRT) responds to economic growth. This paper employed the concept of Transect to compensate for data deficiencies in a long temporal series and established the indicator system from three different aspects- “living function, production function, and ecological function”, to measure MRT along China’s Yangtze River Transect. Our analysis showed that living function and production function display an increasing trend from underdeveloped western regions to eastern economically prosperous regions, and represent a high degree surrounding urban agglomerations, while economic growth only leads to a statistically insignificant decreasing trend in ecological function. The MRT resulting from multiple factors is much diverse, complex, sophisticated, therefore, it should be understood within a framework incorporating both endogenous and exogenous factors. According to the results, it is thus important to formulate differentiated managerial countermeasures corresponding to the economic development level rather than the uniform regulations.

To reduce losses from the various disasters, regional water security evaluation and risk control model is studied. The model is built upon different kinds of indices in water security system, proceeding from the whole structure and its parts of evaluation, forewarning and decision making analysis. Based on China's national conditions, this study firstly advances an evaluation index system of regional water security, which includes three subsystems of water resource security, water environment security, and water disaster control security. Secondly, fuzzy analytic hierarchy process based on accelerating genetic algorithm (AGA-FAHP) combines with entropy weight method (EW) to determine the objective weights of evaluation indexes. The subjective and objective weights can be integrated by the principle of minimum relative information entropy. The subsystem weights are obtained by using AGA-FAHP. Then regional water security evaluation model is established. Thirdly, the comparison judging method is adopted to divide warning degree of water security with the comprehensive evaluation index and forewarning standards, and then the local conditions for proposing planning schemes. Finally, decision making analysis is employed to find the effective indices based on projection pursuit technique with the ideal point method in multi-index decision. This study takes Jiangsu province, China as an example. The evaluation results from 2000 to 2015 show that the development trend of water security is increasing on the whole except in several individual years. Risk forewarning doesn't take place in recent years. But risk is always there. So, project and non-project measures are proposed for the corresponding forewarning levels. From light warnings for three times and moderate warning for once in 2000, 2001, 2002, and 2004, index 1, 3, 4, 11, 13, 17, and 18 are selected as the effective indices to decision making analysis in common. Then, the solution schemes are given as the processing method accordingly. This conclusion is reasonable and its method is practical that match the reality. It suggests that the presented model is feasible with theory and application, which can offer advice in regional water security management to some extent.

The low-cost and high-capacity micron silicon is identified as the suitable anode material for high-performance lithium-ion batteries (LIBs). However, the particle fracture and severe capacity fading during electrochemical cycling greatly impede the practical application of LIBs. Herein, we first proposed an in situ reduction and template assembly strategy to attain a weave cage-like carbon nanostructure, composed of short carbon nanotubes and small graphene flakes, as a flexible nanotemplate that closely wrapped micron-sized mesoporous silicon (PSi) to form a robust composite construction. The in situ formed weave cage-like carbon nanostructure can remarkably improve the electrochemical property and structural stability of micron-sized PSi during deep galvanostatic cycling and high electric current density owing to multiple attractive advantages. As a result, the rechargeable LIB applying this anode material exhibits improved initial Coulombic efficiency (ICE), excellent rate performance, and cyclic stability in the existing micron-sized PSi/nanocarbon system. Moreover, this anode reached an approximation of 100% ICE after only three cycles and maintains this level in subsequent cycles. This design of flexible nanotemplated platform wrapped micron-sized PSi anode provides a steerable nanoengineering strategy toward conquering the challenge of long-term reliable LIB application.

Cadmium (Cd) is a heavy metal that is widely present in modern industrial production. It is a known, highly toxic environmental endocrine disruptor. Long-term exposure to Cd can cause varying degrees of damage to the liver, kidney, and reproductive system of organisms, especially the male reproductive system. This study aimed to explore the mechanism of Cd toxicity in the male reproductive system during puberty. Eighteen healthy 6-week-old male Sprague–Dawley rats were randomly divided into three groups (control group, low-dose group, and high-dose group) according to their body weight, with six in each group. Cd (0, 1, and 3 mg/kg/day) was given by gavage for 28 consecutive days. The results showed that Cd exposure to each dose group caused a decrease in the testicular organ coefficient and sperm count, compared with the control group. Cd exposure resulted in significant changes in testicular morphology in the 3 mg/kg/day Cd group. In the 1 and 3 mg/kg/day Cd groups, serum testosterone decreased and apoptosis of testicular cells increased significantly ( p < 0.05). In addition, compared with the control group, the activity of glutathione peroxidase and superoxide dismutase in each Cd exposure dose group decreased, but the content of malondialdehyde in the high-dose, 3 mg/kg/day Cd treatment group significantly increased ( p < 0.05). Although Cd exposure caused an increase in the messenger RNA (mRNA) levels of Bcl-2, Caspase-3 and Caspase-9 in the testicular tissues ( p < 0.05), Bcl-2 expression was unchanged ( p > 0.05). The expression level of Akt mRNA in testicular tissue of rats in the high-dose 3 mg/kg/day Cd group was increased ( p < 0.05). Our data suggest that Cd affected testosterone levels, and apoptosis was observed in spermatids.

To improve the pyrolytic carbon (PyC) deposition rate of Carbon/Carbon (C/C) composites prepared by the traditional chemical vapor infiltration (CVI) method, the 3D Ni/wood-carbon (3D Ni/C) catalyst was introduced into the CVI process. The effects of catalyst on the density of C/C composites were studied, and the deposition rate and morphologies of PyC were investigated after catalytic CVI. The morphologies of catalyst and PyC were characterized by scanning electron microscope and polarized light microscopy. The catalytic deposition mechanism of PyC was studied by density functional theory. The experimental results show that the initial carbon deposition efficiency of the catalytic pyrolysis process was 3–4 times that of the noncatalytic process. The catalyst reduced the energy barrier in the first step of deposition reaction from 382.55 to 171.67 kJ/mol according to simulation results. The pyrolysis reaction energy with Ni catalyst is reduced by 54% than that without the catalyst.

Intertwining quantum order and non-trivial topology is at the frontier of condensed matter physics1–4. A charge-density-wave-like order with orbital currents has been proposed for achieving the quantum anomalous Hall effect5,6 in topological materials and for the hidden phase in cuprate high-temperature superconductors7,8. However, the experimental realization of such an order is challenging. Here we use high-resolution scanning tunnelling microscopy to discover an unconventional chiral charge order in a kagome material, KV3Sb5, with both a topological band structure and a superconducting ground state. Through both topography and spectroscopic imaging, we observe a robust 2 × 2 superlattice. Spectroscopically, an energy gap opens at the Fermi level, across which the 2 × 2 charge modulation exhibits an intensity reversal in real space, signalling charge ordering. At the impurity-pinning-free region, the strength of intrinsic charge modulations further exhibits chiral anisotropy with unusual magnetic field response. Theoretical analysis of our experiments suggests a tantalizing unconventional chiral charge density wave in the frustrated kagome lattice, which can not only lead to a large anomalous Hall effect with orbital magnetism, but also be a precursor of unconventional superconductivity. An unconventional chiral charge order is observed in a kagome superconductor by scanning tunnelling microscopy. This charge order has unusual magnetic tunability and intertwines with electronic topology.

Melamine has been illegally adulterated in dairy food because of the rich nitrogen content and stable chemical properties in recent years. Therefore, the detection of melamine is of great significance for food safety supervision and human health protection. As melamine is a weak fluorescent substance, it is difficult to detect melamine directly by fluorescence spectroscopy. In this work, we found that melamine can significantly enhance the emission of the tetracycline–europium (EuTC) complex at 616 nm. Therefore, we took EuTC complex as a fluorescent probe to detect melamine. According to the characterizations of absorption spectra, molecular electrostatic potential distribution, and the time-resolved spectra, we speculated that tetracycline and melamine may form a complex through hydrogen bonding interaction in the melamine-EuTC reaction system, causing the melamine closer approach to Eu3+ and reducing the non-radiative energy loss of water molecules to Eu3+, which significantly enhanced the fluorescence intensity of EuTC. The fluorescence intensity of EuTC complex with melamine concentration in the range of 0.5–40.0 μM shows a good linear relationship, and the correlation coefficient is 0.9951 with the detection limit of 7.85 × 10−8 M. It shows a high sensitivity for the EuTC complex as a fluorescent probe to detect melamine, which provides a supplement and extension for the detection of melamine by fluorescence spectroscopy.

Fine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information on changes in fine roots along a density gradient is limited. In this study, plantations of black locust (Robinia pseudoacacia L.) and Chinese pine (Pinus tabuliformis Carr.) with four density classes were analyzed for the influence of soil and leaf traits on fine root growth. Fine root biomass increased with stand density. High fine root biomass was achieved through increases in the fine root production and turnover rate in the high-density black locust plantations and through an increase in fine root production in the pine plantations. In the high-density Chinese pine stand, there was a high fine root turnover which, coupled with high fine root production, contributed to a high fine root biomass. Overall, fine root production and turnover rate were closely related to soil volumetric water content in both kinds of plantations, while fine root biomass, especially the component of necromass, was related to soil nutrient status, which refers to phosphorous content in black locust plantations and nitrogen content in Chinese pine plantations. There was a close linkage between leaf area index and fine root dynamics in the black locust plantations but not in the pine plantations.

Asarum sieboldii, a well-known traditional Chinese medicinal herb, is used for curing inflammation and ache. It contains both the bioactive ingredient asarinin and the toxic compound aristolochic acid. To address further breeding demand, genes involved in the biosynthetic pathways of asarinin and aristolochic acid should be explored. Therefore, the full-length transcriptome of A. sieboldii was sequenced using PacBio Iso-Seq to determine the candidate transcripts that encode the biosynthetic enzymes of asarinin and aristolochic acid. In this study, 63 023 full-length transcripts were generated with an average length of 1371 bp from roots, stems, and leaves, of which 49 593 transcripts (78.69%) were annotated against public databases. Furthermore, 555 alternative splicing (AS) events, 10 869 long noncoding RNAs (lncRNAs) as well as their 11 291 target genes, and 17 909 simple sequence repeats (SSRs) were identified. The data also revealed 97 candidate transcripts related to asarinin metabolism, of which six novel genes that encoded enzymes involved in asarinin biosynthesis were initially reported. In addition, 56 transcripts related to aristolochic acid biosynthesis were also identified, including CYP81B. In summary, these transcriptome data provide a useful resource to study gene function and genetic engineering in A. sieboldii.

Nicotine-degrading Pseudomonas sp. JY-Q is a preferred strain utilized in reconstituted tobacco process for tobacco waste treatment. However, its efficiency of nicotine metabolism still requires to be improved via genomic technology such as promoter engineering based on genomic information. Concerning upstream module of nicotine metabolic pathway, we found that two homologous genes of nicotine dehydrogenase (nicA2 and nox) coexisted in strain JY-Q. However, the transcriptional amount of nox was 20-fold higher than that of nicA2. Thus, the nicA2 expression required improvement. Combinatorial displacement was accomplished for two predicted endogenous promoters, named as PnicA2 and Pnox for nicA2 and nox, respectively. The mutant with Pnox as the promoters for both nicA2 and nox exhibited the best nicotine metabolic capacity which increased by 66% compared to the wild type. These results suggested that endogenous promoter replacement is also feasible for function improvement of metabolic modules and strain enhancement of biodegradation capacity to meet real environment demand.

In the permafrost regions of the Qinghai-Tibet Plateau (QTP), the permafrost table has a significant effect on the stability of geotechnical engineering. The thermal boundaries and soil properties are the key factors affecting the permafrost table. Complex geological environments and human activities can lead to the uncertainties of thermal boundaries and soil properties. In this paper, an array of field experiments and Monte Carlo (MC) simulations of thermal boundaries and soil properties are carried out. The coefficient of variation (COV), scale of fluctuation (SOF), and autocorrelation distance (ACD) of uncertainties of thermal boundaries and soil properties are investigated. A stochastic analysis method of the probabilistic permafrost table is then proposed, and the statistical properties of permafrost table on the QTP are computed by self-compiled program. The proposed stochastic analysis method is verified with the calculated and measured temperature observations. According to the relationship between ACD and SOF for the five theoretical autocorrelation functions (ACFs), the effects of ACF, COV, and ACD of soil properties and the COV of thermal boundaries on the permafrost tables are analyzed. The results show that the effects of different ACFs of soil properties on the standard deviation (SD) of permafrost table depth are not obvious. The SD of permafrost table depth increases with time, and the larger the COVs of thermal boundaries and soil properties, the deeper the SD of permafrost table; the longer the ACD of soil properties, the shallower the SD of permafrost table. This study can provide a reference for the stability analysis of geotechnical engineering on the QTP considering the uncertainties of thermal boundaries and soil properties.

Low gravity fields have been simulated through magnetic acceleration to conduct experimental study on bearing capacity of circular footings on a type of crushable planetary regolith simulant, which has comparable density and particle size distribution of lunar soil. The load–settlement responses of surface spread footings are obtained by investigating the relative density, footing size and gravity effects. Applying the hyperbolic asymptote method, normalised foundation stiffness and ultimate bearing capacity are obtained by curve fitting and predicted by power functions using multivariate nonlinear regression. The results show that the nonlinear gravity effect is not negligible, related to stress condition, soil dilatancy and mobilised friction angle. A cone penetration test (CPT)-based method for prediction of bearing capacity is proposed with correlations between ultimate bearing capacity of footings and shallow penetration stiffness of CPTs, avoiding the uncertainties of soil property estimations. Analyses of allowable bearing capacity and footing influence zone in consideration of footing size and gravity effects could therefore improve the design of shallow foundations on the Moon and Mars, and provide new understandings and potential implications to the bearing capacity of shallow foundations on crushable granular material in both terrestrial and extraterrestrial geotechnical engineering.

Mg K-shell x-ray production cross sections have been investigated for the impact of H+, He2+ and highly charged heavy ions Xe20+ and Eu20+ in the energy range near the Bohr velocity. The x-ray production cross sections were extracted from the yield and compared with various theoretical calculations. It is found that, with the same incident energy per nucleon, the cross section induced by light ions is lower than that produced by highly charged heavy ions by a factor of about 104. With the impact of H+ and He2+ ions, the x-ray emission cross section can be well predicted by ECPSSR theory. However, for the bombardment of highly charged heavy ions, the BEA calculation, corrected both by Coulomb repulsion and effective nuclear charge, results in a good estimation to the experimental data.

Non-uniformity is a common phenomenon in infrared imaging system, which seriously affects imaging quality. In view of the problems of existing non-uniformity correction of infrared images, such as loss of image details and blurred edge of image, an improved non-uniformity correction method of infrared images based on convolution neural network using long-short connections (LSC-CNN) is proposed. The proposed method designs a long-short connection residual network structure suitable for non-uniformity correction of infrared image.The network depth is increased to fully learn the noise by short connections, image sizes are adjusted to reduce the number of parameters, the long connection is used to solve the problem of image information loss caused by transposed convolution, and a multiply operation is carried out to enhance the contrast of corrected images. Besides, batch normalization is utilized to improve the training speed. The experimental results show that LSC-CNN has excellent performance in non-uniformity correction of infrared images whether qualitative evaluation or quantitative evaluation. LSC-CNN is especially effective in image detail preservation and image edge protection whose average PSNR exceeds 37.5 dB and the average SSIM is greater than 0.98.

One component of the Joint United Nations Programme on HIV/AIDS (UNAIDS) goal to end the HIV/AIDS epidemic by 2030, is that 95% of all persons receiving antiretroviral therapy (ART) achieve viral suppression.† Thus, testing all HIV-positive persons for viral load (number of copies of viral RNA per mL) is a global health priority (1). CDC and other U.S. government agencies, as part of the U.S. President's Emergency Plan for AIDS Relief (PEPFAR), together with other stakeholders, have provided technical assistance and supported the cost for multiple countries in sub-Saharan Africa to expand viral load testing as the preferred monitoring strategy for clinical response to ART. The individual and population-level benefits of ART are well understood (2). Persons receiving ART who achieve and sustain an undetectable viral load do not transmit HIV to their sex partners, thereby disrupting onward transmission (2,3). Viral load testing is a cost-effective and sustainable programmatic approach for monitoring treatment success, allowing reduced frequency of health care visits for patients who are virally suppressed (4). Viral load monitoring enables early and accurate detection of treatment failure before immunologic decline. This report describes progress on the scale-up of viral load testing in eight sub-Saharan African countries from 2013 to 2018 and examines the trajectory of improvement with viral load testing scale-up that has paralleled government commitments, sustained technical assistance, and financial resources from international donors. Viral load testing in low- and middle-income countries enables monitoring of viral load suppression at the individual and population level, which is necessary to achieve global epidemic control. Although there has been substantial achievement in improving viral load coverage for all patients receiving ART, continued engagement is needed to reach global targets.

Artificial skins with sensing ability have great potential in applications of wearable devices and soft robotics. Inspired by the functions of human skins including sensing stimuli via electrical signal and bruising for injury indication, an ionic conductive and mechanochromic organohydrogel is synthesized and demonstrated as ionic skin (I-skin). The gel consisting of mechanochromophore cross-linked micelles is mechanically robust, stretchable, and deformation durable with minor hysteresis, and it also displays good solvent retention. The change of relative resistance during elongation and compression suggests a high sensitivity. An optical change from pale yellow to bruise-like blue-purple color is observed under a large deformation. The ionic conductive organohydrogel as I-skin is attached to different parts of the human body with movements mimicking various body-bruising scenarios, demonstrating successful perception and visualization of mechanical stimuli. The work vividly presents a strain sensor with the functions of injury visualization and damage warning for mechanical impacts. The I-skin can be potentially used in the applications including prosthetic devices, wearable electronics, and intelligent robots.

Sodium-ion batteries (SIBs), being an attractive candidate of lithium-ion batteries, have attracted widespread attention as a result of sufficient sodium resource with low price and their comparable suitability in the field of energy storage. However, one of the main challenges for their wide-scale application is to develop suitable anode materials with excellent electrochemical performance. Herein, a novel orderly layered VMoS2 (OL-VMS) anode material was synthesized through a facile hydrothermal self-assembly approach followed by a heating procedure. As the anode material of the SIBs, the unique structure of OL-VMS not only facilitated the rapid migration of sodium ions between the stacked layers but also provided a stable framework for the volume change in the process of intercalation/deintercalation. In addition, vanadium mediating in the framework caused more defects to produce abundant storage sites for Na+. As such, the obtained OL-VMS-based anode exhibited high reversible capacities of 602.9 mAh g-1 at 0.2 mA g-1 and 534 mAh g-1 even after 190-cycle operation at 2 A g-1. Furthermore, the OL-VMS-based anode delivered an outstanding specific capacity of 626.4 mAh g-1 after 100-cycle testing at 2 A g-1 in a voltage range from 0.01 to 3 V. In particular, even in the absence of conductive carbon, it still showed an excellent specific capacity of 260 mAh g-1 at 1 A g-1 after 130 cycles in a 0.3-3 V voltage range, which should contribute to the cost reduction and energy density increase.

The South China Sea (SCS) experienced a significant reduction in warming rate (− 0.01 °C decade−1, $$p>0.10$$ p > 0.10 ) during 1999–2010 following an accelerated and unprecedented warming (+ 0.15 °C decade−1, $$p p < 0.01 ) in the last three decades (1970–1998). However, most global climate models of the CMIP5 RCP4.5 scenario failed to capture this SCS warming slowdown. In this study, we identify two drivers through numerical simulations by using a regional high-resolution, ocean–atmosphere coupled climate model: the major variance (75%) in the sea surface warming slowdown could be explained by the strengthened winter monsoon over the SCS, and the minor variance (12%) could be explained by the changes in the upper ocean circulations. The winter monsoon over the SCS is likely linked to the La Niña-like SST pattern in the eastern tropical Pacific, which strengthens the Walker circulation and results in anticyclonic circulation over the northwestern Pacific. This enhanced winter monsoon is the atmospheric driver that slows down the SCS basin-scale warming, while the largest reduction of the warming rate occurs in the northern SCS that can be attributed to the oceanic throughflow via the Luzon Strait. These findings could have important implications for future climate projections over the SCS and adjacent oceans.

Proteins containing nuclear localization signals (NLSs) are actively transported into the nucleus via the classic importin-α/β-mediated pathway, and NLSs are recognized by members of the importin-α family. Most studies of insect importin-αs have focused on Drosophila to date, little is known about the importin-α proteins in Lepidoptera insects. In this study, we identified four putative importin-α homologs, Spodoptera frugiperda importin-α1 (SfIMA1), SfIMA2, SfIMA4 and SfIMA7, from Sf9 cells. Immunofluorescence analysis showed that SfIMA2, SfIMA4 and SfIMA7 localized to the nucleus, while SfIMA1 distributed in cytoplasm. Additionally, SfIMA4 and SfIMA7 were also detected in the nuclear membrane of Sf9 cells. SfIMA1, SfIMA4 and SfIMA7, but not SfIMA2, were found to associate with the C terminus of AcMNPV DNA polymerase (DNApol) that harbors a typical monopartite NLS and a classic bipartite NLS. Further analysis of protein-protein interactions revealed that SfIMA1 specifically recognizes the bipartite NLS, while SfIMA4 and SfIMA7 bind to both monopartite and bipartite NLSs. Together, our results suggested that SfIMA1, SfIMA4 and SfIMA7 play important roles in the nuclear import of AcMNPV DNApol C terminus in Sf9 cells. This article is protected by copyright. All rights reserved.

Preeclampsia (PE) is a pathologic condition in pregnant women which accounts for the inhibition of proliferation, migration and invasion of trophoblast cells. This study aimed to investigate the regulation of ubiquitin-specific peptidase 5 (USP5) on the trophoblast cells in PE. Expressions of USP5 in the placentas of PE patients and healthy donors were examined by qRT-PCR and Western blot. Hypoxia/reoxygenation (H/R) model in trophoblast cells was further established. Cell viability was examined using CCK-8 assay. Finally, the effect of overexpression and silence of USP5 using lentivirus transduction was studied. Our results showed that USP5 was lowly expressed in the placentas of PE patients as well as in H/R-induced trophoblast cells. In the experiments of overexpression, USP5 promoted the proliferation of trophoblast cells, and up-regulated the expressions of β-catenin and the downstream signals c-Myc and Cyclin D1 in trophoblast cells. On the other hand, silence of USP5 elicited the opposite results. The overexpression of USP5 in the H/R model greatly released the H/R-induced inhibition in the trophoblast cells, and moderated the down-regulation of β-catenin and c-Myc induced by H/R. We concluded that USP5 promoted the proliferation of trophoblast cells via the up-regulation of the Wnt/β-catenin signaling pathway.

With the gradual reduction of mineral resources, marine mining has increasingly been developed as a method of exploiting resources. However, the cutting efficiency of submarine mineral deposits requires additional improvement. Investigating the preferable cutting efficiency in marine mining, it is important to establish a theoretical model of predicting the peak cutting force for polymetallic sulfide. The polymetallic sulfide was taken from the floor of the Indian Ocean and maintained at constant temperature and humidity conditions during transportation. In the paper, some experiments were conducted to study the physicomechanical properties of polymetallic sulfide. And the cutting experiments were conducted to investigate the cutting force at room temperature and atmosphere pressure, preliminarily. Then, based on maximum tensile stress theory, the theoretical equation of predicting the peak cutting force was derived, and an improved high-precision theoretical model was established. The reliability and accuracy of this model was verified using the experimental data. Based on the improved theoretical model, the brittleness index and the cutting depth, which influenced the peak cutting force, were investigated. Results show that the established model improved the accuracy of predictions. The peak cutting force decreased with the increase of the brittleness index, but it increased with the increase of the depth, which followed the power-law pattern. The power-law coefficient was generally at 1-2. The experiments verified that this improved theoretical model and the related conclusions can predict the peak cutting force. It is significant for the design and study of conical picks and cutting mechanisms in marine mining.

In this paper, the initiation characteristics of the oblique detonation flow field induced by single- and double-wedge surfaces of finite length in a confined space are investigated. Numerical simulations with a detailed H2/air reaction and theoretical shock polar analyses are combined to study the influence mechanism of a complex wave system structure on the characteristics of the oblique detonation. The effects of expansion waves on the oblique detonation waves (ODWs) and their flow field characteristics for different equivalent ratios and geometric sizes are analyzed in single-wedge and double-wedge structures with the same inflow parameters. The results show that the length of the induced ODW is shorter in the double-wedge structure than in the single-wedge structure. For the single-wedge structure, the strength of the expansion wave increases, the wall temperature drops, and the characteristic length of the induction zone decreases with increasing deflection angle of the second wedge. If the strength of the expansion wave is sufficiently large, the ODW is initiated. For the double-wedge structure, the ODWs interact and form a complex wave system structure, consisting of a Mach stem, two reflected detonation waves and slip lines. The length and the temperature before and after the Mach stem decrease with an increase in the strength of the expansion waves. The effects of the expansion waves on the flow field of the ODW are relatively small at a large equivalent ratio and significantly larger at a small equivalent ratio.

Warming on Earth’s Third Pole is leading to rapid loss of ice and the formation and expansion of glacial lakes, posing a severe threat to downstream communities. Here we provide a holistic assessment of past evolution, present state and modelled future change of glacial lakes and related glacial lake outburst flood (GLOF) risk across the Third Pole. We show that the highest GLOF risk is at present centred in the eastern Himalaya, where the current risk level is at least twice that in adjacent regions. In the future, GLOF risk will potentially almost triple as a consequence of further lake development, and additional hotspots will emerge to the west, including within transboundary regions. With apparent increases in GLOF risk already anticipated by the mid-twenty-first century in some regions, the results highlight the urgent need for forward-looking, collaborative, long-term approaches to mitigate future impacts and enhance sustainable development across the Third Pole. Global warming-driven deglaciation in high-mountain Asia raises the likelihood of natural dam failure and associated glacial lake outburst flood risk. This is estimated for lake development under present-day and future warming scenarios, highlighting emerging hotspots and transboundary impacts.

The presence of pesticide residues has become one of the main risk factors affecting the safety and quality of agro-food. In this study, a multi-residue method for the analysis of 284 pesticides in five local fruit cultivars in Shanghai was developed based on ultrahigh-performance liquid chromatography-quadrupole time-of-fight mass spectrometry (UPLC-QTOF/MS). The limits of determination and the limits of quantitation of pesticides were 0.6–10 and 2–30 µg/kg, respectively. A total of 44, 10, 10, 18, and 7 pesticides were detected in strawberries, watermelons, melons, peaches, and grapes, respectively. The pesticide levels in 95.0% of the samples were below the maximum residual limits (MRLs) prescribed by China, and in 66.2% of the samples below the EU MRLs. The dietary risk assessment study showed big differences in the chronic and acute exposure risk values among different Chinese consumer groups. Through fruit consumption, children/females showed higher exposure risks than adults/males. But both the risk values were less than 100%, indicating that potential dietary risk induced by the pesticides was not significant for Chinese consumers. Nevertheless, certain measures are needed for both growers and government in order to decrease the MRL-exceeding rate of pesticide residues and ensure the quality and safety of fruits for consumers.

TPGS approved by FDA can be used as a P-gp inhibitor to effectively reverse multi-drug resistance (MDR) and as an anticancer agent for synergistic antitumor effects. However, the comparatively high critical micelle concentration (CMC), low drug loading (DL) and poor tumor target limit its further clinical application. To overcome these drawbacks, the pH-sensitive star-shaped TPGS copolymers were successfully constructed via using pentaerythritol as the initial materials, ortho esters as the pH-triggered linkages and TPGS active-ester as the terminated MDR material. The amphiphilic star-shaped TPGS copolymers could self-assemble into free and doxorubicin (DOX)-loaded micelles at neutral aqueous solutions. The micelles exhibited the lower CMC (8.2 × 10−5 mg/ml), higher DL (10.8%) and long-term storage and circulation stability, and showed enhanced cellular uptake, apoptosis, cytotoxicity, and growth inhibition for in vitro MCF-7/ADR and/or MCF-7/ADR multicellular spheroids and in vivo MCF-7/ADR tumors via efficiently targeted drug release at tumoral intracellular pH (5.0), MDR reversal of TPGS, and synergistic effect of DOX and TPGS. Therefore, the pH-sensitive micelles self-assembled from star-shaped TPGS copolymers with ortho ester linkages are potentially useful to clinically transform for enhanced MDR cancer treatment., Graphical abstract pH-sensitive micelles self-assembled from star-shaped TPGS copolymers for enhanced apoptosis, cytotoxicity, and growth inhibition for in vitro MCF-7/ADR multicellular spheroids and in vivo MCF-7/ADR tumors.Image, graphical abstract

Fire zone sealing is an important approach to fire extinguishment and disaster relief. The study is aimed at investigating the distributions and evolutions of temperature and CH4 concentration fields during fire zone sealing and revealing the mechanism of sealing-induced gas explosion accidents. Firstly, the models of O2 consumption, heat production and products of coal combustion were constructed based on the Arrhenius equation of chemical reaction rate, and meanwhile the mathematical models of gases and temperature field in the sealing process were established. Besides, the variations of airflow volume, temperature and CH4 and O2 concentrations during and after fire zone sealing were numerically simulated. The results show that in the sealing process, the airflow into the fire zone gradually decreases, and air begins to flow out through the air intake at the later stage. After the completion of fire zone sealing, the temperature at fire source decreases briefly, then gradually increases and finally goes down. The temperature in the whole fire zone, except the fire source, also decreases first, then rises and finally falls gradually. The sealing raises the overall CH4 concentration in the fire zone, and the CH4 concentration at the air return side is always higher than that at the air intake side. When the sealed flow field gradually recovers to a steady flow field, the CH4 concentration goes up slowly under the influence of CH4 release. The research is of great significance for grasping the development of mine fire and the evolution of flow field in the sealing process and can provide guidance for the prevention of gas explosion accidents.

C/MgO composite powders were prepared by combustion synthesis using magnesium oxalate and magnesium powders as raw materials. The phase composition and microstructure of the composite powders were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy/energy dispersive spectroscopy (FESEM/EDS), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The synthetic mechanism was explored through TG-FTIR and combustion front quenching techniques. It was found that the C/MgO composite powders contained a large quantity of MgO nanofibers. When the molar ratio of magnesium oxalate and magnesium was 1:4, the carbon content of the product reached a maximum of 9.45 wt %. In the composite powders, cubic MgO particles were encapsulated by a thin carbon layer, and there was a tiny gap between MgO and the carbon layer; a large number of MgO nanofibers with aspect ratios of 80–100 were found. The cubic MgO particles of the products are the direct decomposition of MgC2O4, and the MgO nanofibers are the reaction product of gaseous Mg and CO2/CO at high temperature. Meanwhile, the carbon deposited on the MgO particles can inhibit the grain growth of MgO particles and result in the refinement of MgO particles. The uniform dispersion of carbon and the weak C/MgO interface combine, making the composite powders a potential additive for low-carbon MgO–C refractories with excellent thermal shock resistance.

Electrolyte formulation with high stability towards both Li metal anode and high-voltage cathode is considered as one of key points for the high-energy density lithium metal batteries (LMBs). In our previous study, by adding only 2% of 2-fluoropyridine (2-FP) as the additive in the carbonate and ether-based electrolyte formulations effectively suppressed Li dendrite growth. In this study, we further found that the main fluoropyridine (FP) family members can serve as not only the effective additive but also the excellent electrolyte solvent in the electrolyte formulations to enhance the performance of LMBs. For the 2-FP, when it was also used the electrolyte solvent and paired with single-salt lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), the obtained electrolyte formulation of 1 M LiTFSI in pure 2-FP solvent not only allowed faster ion transport though solvation effect, but also possessed impressive oxidation stability window over 4.3 V. As a result, the high-voltage LiNi1/3Mn1/3Co1/3O2 (1.5 mA h cm−2)|Li metal battery with it exhibited a capacity retention of more than 80 % over a long-term cycle even at 0.45 mA cm−2 with a lean electrolyte (30 μL). Meanwhile, for another FP family member (i.e., 3-FP) as the electrolyte additive, the 4.3 V LMBs with the carbonate-based electrolyte containing only 1% of 3-FP maintained 83.9 % of initial capacity after 200 cycles at 0.75 mA cm-2. Density functional theory (DFT) calculations and experiments confirmed that three typical FPs, i.e., 2-FP, 3-FP and 4-FP can not only regulate the initial Li nucleation process, but more importantly also induce a protective layer, leading to a uniform and dendrites-free Li deposition. This bifunction of the FP family member as either electrolyte solvent or additive in the electrolyte formulations should be promising for the achieving of dendrites-free high-energy density LMBs.