Search

A mechanically strong binder with polar functional groups could overcome the dilemma of the large volume change during charge/discharge processes and poor cyclability of lithium-sulfur batteries (LSBs). In this work, for the first time, we report the use of poly(thiourea triethylene glycol) (PTTG) as a multifunctional binder for sulfur cathodes to enhance the performance of LSBs. As expected, the PTTG binder facilitates the high performance and stability delivered by the Sulfur-PTTG cathode, including a higher reversible capacity of 825 mAh g−1 at 0.2 C after 80 cycles, a lower capacity fading (0.123% per cycle) over 350 cycles at 0.5 C, a higher areal capacity of 2.5 mAh cm−2 at 0.25 mA cm−2, and better rate capability of 587 mAh g−1 at 2 C. Such superior electrochemical performances could be attributed to PTTG's strong chemical adsorption towards polysulfides which may avoid the lithium polysulfide shuttle effect and excellent mechanical characteristics which prevents electrode collapse during cycling and allows the Sulfur-PTTG electrode to maintain robust electron and ion migration pathways for accelerated redox reaction kinetics.

In this study, Ni/Al2O3 was prepared with an impregnation method for CO2 hydrogenation into carbon nanofibers (CNFs). High purity CNFs were acquired from CO2 hydrogenation at 500 °C and 1 atm over Ni/Al2O3 catalyst after a liquid phase extraction process, removing the used catalysts and by-products. The particle properties of as-prepared Ni/Al2O3 have been well characterized for comparison with the commercial ones. The results of XPS spectra and XRPD patterns indicated that the commercial, as-prepared, and used Ni/Al2O3 were multicomponent with various crystal phases. The as-prepared Ni/Al2O3 can be sufficiently exposed in CO2 atmosphere for higher catalytic performances owing to its unique microstructure with higher specific surface area (429.2 m2/g). Both EXAFS and XANES spectra have shown that the first shell of Ni atom in commercial, as-prepared, and used Ni/Al2O3 were Ni O with bond distances of 1.61, 1.63, and 1.62 A, respectively. The configuration of fabricated CNFs was characterized by its unique ID/IG (Intensities of D-band/G-band) ratio of 0.23 in the Raman spectrum. Solid tubular shape with 30 nm diameter of CNFs was observed using FE–SEM and HR–TEM. Thermodynamic analyses indicate that CO2 hydrogenation into CNFs is a spontaneous and exothermic reaction with an optimal temperature of 500 °C.

Binders could play crucial or even decisive roles in the fabrication of low-cost, stable and high-capacity electrodes. This is especially the case for the silicon (Si) anodes and sulfur (S) cathodes that undergo large volume change and active material loss in lithium-ion batteries during prolonged cycles. Herein, a hydrophilic polymer poly(methyl vinyl ether-alt-maleic acid) (PMVEMA) was explored as a dual-functional aqueous binder for the preparation of high-performance silicon anode and sulfur cathode. Benefiting from the dual functions of PMVEMA, i.e., the excellent dispersion ability and strong binding forces, the as-prepared electrodes exhibit improved capacity, rate capability and long-term cycling performance. In particular, the as-prepared Si electrode delivers a high initial discharge capacity of 1346.5 mAh g−1 at a high rate of 8.4 A/g and maintains 834.5 mAh g−1 after 300 cycles at 4.2 A/g, while the as-prepared S cathode exhibits enhanced cycling performance with high remaining discharge capacities of 663.4 mAh g−1 after 100 cycles at 0.2 C and 487.07 mAh g−1 after 300 cycles at 1 C, respectively. These encouraging results suggest that PMVEMA could be a universal binder to facilitate the green manufacture of both anode and cathode for high-capacity energy storage systems.

The static recrystallization and associated texture evolution were investigated in an extruded Mg-Zn-Gd alloy with bimodal microstructure based on a quasi-in-situ electron back-scatter diffraction (EBSD) method. The typical rare earth (RE) texture formed during annealing, evolving from the bimodal microstructure with [10 1 ¯ 0] basal fiber texture that consisted of fine recrystallized (RXed) grains and coarse unrecrystallized (unRXed) grains elongated along the extrusion direction. In both RXed and unRXed regions, the RXed nucleation produced randomized orientations without preferred selection and the RXed grains with RE texture orientation had more intensive growth ability than those with basal fiber orientation, thereby leading to the preferred selection of RE texture orientation during grain growth. The relationships between stored strain energy, solute drag, grain growth and texture evolution are discussed in detail. This study provided direct evidence of the RE texture evolution in an extruded Mg-RE alloy, which assists in understanding the formation mechanisms for RE texture during extrusion and better developing wrought Mg alloys with improved formability.

Nickel diselenide (NiSe2) is a promising low-cost catalyst for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), due to its suitable d-electron configuration and high electrical conductivity. Several representative elements, e.g., Co, Fe and P, have been utilized as cation or anion to promote the electrocatalytic activity of NiSe2 by modulating the interaction with Se element, whilst the catalyst stability is less concerned. In this work, the catalytic Ni nanoparticles were in-situ encapsulated in carbon nanotubes grown on three-dimensional conducting carbon framework. Subsequent phosphorization and selenization yield dispersed P-doped NiSe2 nanoparticles protected by carbon shell with highly exposed yet stable active sides, resulting in significantly promoted HER and OER activities as well as accelerated kinetics. In detail, the P-NiSe2@N-CNTs/NC hybrid catalyst deliver low overpotentials of 95 and 306 mV at 10 mA cm−2 for HER and OER in alkaline media, respectively. DFT calculations reveal that P doping reduces the electron density surrounding Ni atoms while accumulates the charges to Se, respectively, which in turn reduces the energy barriers for both water dissociation and intermediates adsorption for both HER and OER. As a concept of proof, a cell assembled by P-NiSe2@N-CNTs/NC hybrid catalyst-based anode and cathode performs a low applied voltage of 1.609 V to reach 10 mA cm−2, and outstanding long-term stability.

Li-rich oxides are considered as the most commercial potential cathode materials due to the high theoretical specific discharge capacity. Here, ZrO2 in different crystalline states are applied as the coating layers to enhance the electrochemical performance of hollow Li[Li0.2Mn0.54Ni0.13Co0.13]O2 materials. Meanwhile, a series of characterizations (XRD, SEM, TEM, EDX etc.) are conducted to compare the effects of ZrO2 coating layer with different crystalline states on the host material. The results elucidate that the Li-rich Mn-based material with the polycrystal ZrO2 coating layer has a slight advantage in rate performance, while the host material with the single crystal ZrO2-coating layer has a better cycling performance and effectively suppresses voltage decay with the effect of excellently inhibiting layered to spinel-like phase transition and metal dissolution during charging and discharging process.

Strontium cobaltite-based perovskites (SrCoO3-δ) have been widely studied as a promising cathode for the next-generation solid-oxide fuel cell (SOFC). Here, we found a balance between oxygen vacancy (VO) formation and its migration in designing SrCoO3-δ-based materials by using two activity descriptors, i.e., radius and electronegativity. The ORR activity of these types of perovskites is found to strongly rely on the two proposed descriptors, and Nb- or Ta-doped SrCoO3-δ locates in the promising zone as predicted with a moderate value of both VO formation energy and ion migration barrier. Then Sc-Ta co-doped SrCoO3-δ (SSTC) and Sc-Nb co-doped SrCoO3-δ (SSNC) are screened out to be the best among 91 bimetal-doped SrCoO3-δ perovskites. Further experiments have been carried out to synthesize the co-doped SSTC and prove ultralow area-specific resistance values (0.071, 0.198, and 0.701 Ω·cm2 at 550, 500, and 450 °C, respectively), which is only one-third of that of benchmark materials for the SOFC cathodes. Our results open a novel pathway in designing SOFC cathodes with an optimal performance.

The volcanic rocks of the Elashan Formation provide important evidence for the Late Triassic post-collisional magmatism in the East Kunlun Orogenic Belt. This study focused on the geochronology, ge...

The homogenized Mg-8.2Gd-3.8Y-1.0Zn-0.4 Zr (wt.%) alloy full of plate-shaped long period stacking ordered (LPSO) phases was hot extruded in the atmosphere and cooled by the forced-air, then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this work. The results show that in comparison with the extruded sample cooling in the atmosphere, the forced-air cooling restricts dynamic recrystallization (DRX) and brings about finer dynamic recrystallized (DRXed) grain size, stronger basal texture and higher dislocation density. Furthermore, the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases and γ′ phases with smaller interspacing in the unrecrystallized (unDRXed) regions, then slightly restricts the precipitation of β′ phases during aging. After peak-ageing treatment, the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa, an ultimate tensile strength of 493 MPa, and elongation to failure of 18.6 %.

Severe stress concentration occurs around circular vent holes of an industrial turbine sealing disk. This paper investigates the structural design and optimization for the vent holes to effectively reduce the maximum von Mises stress and improve the fatigue life of the turbine sealing disk. An efficient integrated design optimization method is presented based on a novel non-circular vent hole design method in combination with a variable dimension sub-model method, a self-developed modeling and meshing tool, and the Multi-Island Genetic Algorithm. The proposed non-circular vent hole is biaxial symmetric and consists of four smoothly connected arcs. The variable dimension sub-model method is utilized to obtain accurate results in the fields around the vent holes within the computationally acceptable time. The modeling and meshing tool is developed by using the Tcl/Tk Scripts to rebuild the geometry and generate the high-quality hexahedral mesh automatically. The Multi-Island Genetic Algorithm is adopted to solve the studied constrained optimization problem. After optimization, the maximum von Mises stress is reduced from 1305.644 MPa to 963.435 MPa, and the fatigue life is increased from 3091 cycles to 30,297 cycles. The results show that the proposed design and optimization methods can significantly improve the performance of the turbine sealing disk along with the remarkable drop in stress concentration.

Ni-rich cathodes exhibit appealing properties, such as high capacity density, low cost, and prominent energy density. However, the inferior ionic conductivity and bulk structural degradation become bottlenecks for Ni-rich cathodes and severely limit their commercial utilization. Traditional coating and doping methods suffer fatal drawbacks in functioning as a unit and cannot radically promote material performance to meet the needs of Li-ion batteries (LIBs). Herein, we successfully devised an ingenious and facile synthetic method to establish Ni-rich oxides with a La2Zr2O7 coating and Zr doping. The coating layer improves the ion diffusion kinetics and enhances Li-ion transportation while Zr doping effectively suppresses the phase transition of LiNi0.8Co0.1Mn0.1O2 cathode. Owing to the synergetic effect of Zr doping and La2Zr2O7 coating, the modified material shows prominent initial discharge capacity of 184.7 mAh g−1 at 5 °C and maintains 177.5 mAh g−1 after 100 cycles at 1 °C. Overall, the proposed feasible electrode design method can have a far-reaching impact on further fabrication of advanced cathodes for high-performance LIBs.

Searching for ultralight microwave absorber with good heat-insulating property is highly desirable to fulfill the technical requirement of modern society. Herein, the two-dimension (2D) graphene-like porous carbon nanosheets (GPCN) derived from the waste pomelo peel were developed. The preparation is performed by a facile hydrothermal process with synergistic usage of HAc and H2O2. Interestingly, the thickness and porosity of GPCN can be readily regulated by adjusting addition amount of the reagents. The related synthetic mechanism is investigated in depth. Compared with traditional graphene, the fabrication strategy of GPCN possesses many advantages, such as low cost, high yield and ease of production. The results show that GPCN presents superior thermal insulation and microwave absorption properties. The heat-insulating property is comparable to commercial products, e.g. polyurethanes (PU), nickel foam (NF), carbon foam (CF). The strong microwave absorption intensity of −56.4 dB and bandwidth of 6.4 GHz is achieved under ultralow filling ratio of 4 wt%. Moreover, the density of assembled 3D macroscopically product is merely 0.01 g/cm−3. The excellent performance should be attributed to the unique 2D morphology and high porosity of GPCN. Our work paves a new way for developing porous carbon nanosheet from sustainable biomass as heat-insulating ultralight microwave absorber.

The aim of this study was to establish a method for geographical origins identification of Panax notoginseng (P. notoginseng) based on abundant chromatographic spectral information. Characteristic fingerprints of P. notoginseng extracts samples were generated by Multi-wavelength Fusion Profiling (MWFP) method based on the HPLC fingerprints established at three wavelengths of 203 nm, 270 nm and 325 nm. The samples grouping results calculated with the averagely linear quantified fingerprint method (ALQFM) and the unsupervised statistical methods based on fusion fingerprints matches with the geographical origins. The Multi-wavelength Fusion Profiling (MWFP) method has been successfully applied to identification of geographical origins of P. notoginseng and shows the advantages compared with single—channel fingerprints. In addition, eight physiologically active components, including four saponins, two flavones and two amino acids, were identified from the most relevant ingredients of P. notoginseng geographical origins by fusion fingerprint-efficacy relationship analysis. Besides the recognized active saponins, other categories of active ingredients such as flavonoids and amino acids should be paid attention to in the producing areas identification or the quality judgment of P. notoginseng.

The live working paths for equipotential operators in the hanging basket method is determined by minimum safety values of various clearances stipulated in regulations. However, the optimization of the safety path planning by the complex gaps is scarce. In this paper, an optimization method for path planning is proposed based on ant colony algorithm. Grid model is established to partition the operation area into different calculation districts, in which key parameters are grid data and obstacle grids. Grid data are the maximum value of the electric field strength on the body surface, calculated by the finite element model. And obstacle grids are grids that dissatisfy the requirements of complex gaps and their data are larger than the air breakdown field strength. Then ant colony algorithm is employed to search for the best operation path with the minimum working distance and the minimum electric field strength value. After that, an application case is illustrated to demonstrate the optimizing processes. At last, the shock U50 test and power frequency corona discharge test are implemented to verify the safety of the optimized path. Therefore, the path obtained by the proposed method scientifically and effectively shortens the distance of the hanging basket method.

We have experimentally studied the stable trapping and rotation of silica microspheres using canonical vortex (CV) beam and power-exponent-phase vortex (PEPV) beam. Numerical simulation was carried...

The ester functionality is commonly seen in the areas of chemical biology and medicinal chemistry for the design of cell‐permeable active molecules. Ester‐based pro‐drug/pro‐sensor strategies are employed to mask polar functional groups (i. e. carboxylic acids) and improve the overall cell permeability of these functional molecules. However, their use as reactive units for sensing applications, including bacterial detection, has not been fully explored. Herein, we synthesised two TCF‐based fluorescent probes, TCF‐OAc and TCF‐OBu. As expected, both TCF‐OAc and TCF‐OBu demonstrated a significant fluorescence (22‐ and 43‐fold, respectively) and colorimetric response (yellow to purple) towards porcine liver esterase (PLE) with a limit of detection of 1.18 mU/mL and 0.45 mU/mL, respectively. With these results in hand, the ability of these probes to detect planktonic suspensions of gram‐positive Staphylococcus aureus (S. aureus) and gram‐negative Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli) were evaluated. Different fluorescence responses for gram‐positive and gram‐negative bacteria were observed between TCF‐OAc and TCF‐OBu. After 1 h incubation, TCF‐OAc proved more sensitive towards S. aureus, demonstrating a significant fluorescence “turn on” response (16‐fold); whereas, TCF‐OBu was more selective towards P. aeruginosa, with a 22‐fold increase in the fluorescence response observed. These results demonstrate the influence of the ester chain length on the selectivity for bacterial species.

Previous work showed that particle behaviors in ultrasonic atomization pyrolysis (UAP) reactor have a great influence on the transport and collection of particles. In this study, the effects of droplet behaviors (i.e. droplet collision and breakage) and solvent evaporation on the droplet size, flow field and collection efficiency during the preparation of ZnO particles by UAP were investigated. The collision, breakage and solvent evaporation conditions which affect the droplet size distribution and flow pattern were considered in CFD simulation based on Eulerian-Lagrangian method. The results showed that droplet collision and breakage would increase the droplet size, broaden the droplet size distribution and hinder the transport of droplets. Solvent evaporation obviously changed the flow pattern of droplets. In addition, both droplet behaviors and solvent evaporation reduced the collection efficiency. This study could provide detail information for better understanding the effect of droplet behaviors and solvent evaporation on the particle production process via UAP reactor.

To enhance ammonia nitrogen (NH3-N) and phosphate (PO43--P) removal in hyper-eutrophic water, electrolysis-enhanced ecological floating bed (EEEFB) was designed with a Mg-Al alloy anode, a Ir-Ta-Ti metal oxide-coated titanium anode, and an Fe anode with the same graphite cathode. The results showed that the Mg-Al alloy anode with graphite cathode had a better ability to enhance NH3-N and PO43--P removal. When the current density was 0.37 mA·cm-2, the electrolysis time was 24 h/d, and the net removal rates of NH3-N and PO43--P were 62% and 99.4%, respectively. In winter, the purification efficiencies of NH3-N and PO43--P were as high as 7388.4 mg·m-2 and 4297.5 mg·m-2, respectively, by EEEFBs which were significantly higher than the traditional ecological floating bed (p < 0.05). Scanning electron microscopy (SEM) and X-ray spectrometry confirmed that the PO43--P was deposited in the sediment of EEEFBs with Mg-Al alloy anode and Fe anode.

Enzyme-responsive drug delivery systems (DDSs) have shown great potential in the diagnosis and treatment of cancer. Nitroreductase (NTR) that plays an essential role in the reduction of nitro compounds has been found to be overexpressed in tumor cells than in normal cells. Here, we present an amphiphilic polymer TNP that is flanked by an NTR responsive 4-nitrobenzyl group, hydrophobic AIE tetraphenylethylene (TPE), and polyethylene glycol hydrophilic moieties, which can be self-assembled into micelles to efficiently encapsulate the hydrophobic drug doxorubicin (DOX) in aqueous solution. In the presence of NADH, the 4-nitrobenzyl unit of TNP is reduced by NTR, leading to the decomposition of the TNP micelles and DOX release with the detection limit as low as 2.6 ng mL−1. MTT assays showed that TNP@DOX micelles possess an obvious toxicity against cancer cells, while negligible toxicity towards normal cells was observed. With the advantage of the AIE properties of TNP, the TNP@DOX micelles were able to be efficiently endocytosed by HeLa cells, and release DOX in a selective manner as determined by confocal laser scanning microscopy (CLSM) and flow cytometry (FCM) analyses. This work provides a promising nanoplatform for cancer diagnosis and treatment with controlled drug release.

As a clean, eco-friendly and sustainable process, electrocatalysis has potential to replace the energy-consuming and environment-polluting Haber–Bosch process for N2 fixation. Although ruthenium (Ru) is generally considered as the best electrocatalyst for this process, its low faradaic efficiency greatly hampers the practical applications. Considering the solvent effects, our ab initio calculations and micro-kinetic simulations indicate that doping oxygen into the sublayer of Ru(0001) can turn some surface Ru0 atoms into positively charged Ru+, significantly boosting the reduction of N2. The overpotential can be dramatically reduced to 0.18 V only for Ru(0001) with 1.00 ML subsurface oxygen. Notably, the calculated turnover frequency (TOF) is 3.64 × 10−2 per s per site at 700 K and 100 bar, which is hundreds of times greater than that of the pure Ru(0001) surface. In terms of experimental progress on the successful incorporation of subsurface oxygen into the Ru(0001) surface, our work offers a practical and feasible route to boost electrochemical reduction of N2 to ammonia.

We report that atomically thin two-dimensional silicon quantum sheets (2D Si QSs), prepared by a scalable approach coupling chemical delithiation and cryo-assisted exfoliation, can serve as a high-performance brain photonic nanoagent for orthotopic glioma theranostics. With the lateral size of approximately 14.0 nm and thickness of about 1.6 nm, tiny Si QSs possess high mass extinction coefficient of 27.5 L g−1 cm−1 and photothermal conversion efficiency of 47.2% at 808 nm, respectively, concurrently contributing to the best photothermal performance among the reported 2D mono-elemental materials (Xenes). More importantly, Si QSs with low toxicity maintain the trade-off between stability and degradability, paving the way for practical clinical translation in consideration of both storage and action of nanoagents. In vitro Transwell filter experiment reveals that Si QSs could effectively go across the bEnd.3 cells monolayer. Upon the intravenous injection of Si QSs, orthotopic brain tumors are effectively inhibited under the precise guidance of photoacoustic imaging, and the survival lifetime of brain tumor-bearing mice is increased by two fold. Atomically thin Si QSs with strong light-harvesting capability are expected to provide an effective and robust 2D photonic nanoplatform for the management of brain diseases.

The magneto-refractive properties of Er/Yb co-doped silica fiber (EYDF) are important in magnetic field sensing. Here, we proposed a theoretical calculation model of the EYDF using density functional theory (DFT) and demonstrated it by an interferometric digital hologram magneto-refractive measurement system. The calculation results show that the fiber material, doped with Er/Yb atoms, has a large net spin and asymmetric spin distribution, which enables the elements to play an important role in the magnetic characteristics of the material. The experimental results show that the refractive index of the fiber decreases linearly with the increase of the magnetic field. The sensitivity of EYDF is 3.8279 × 10-5 RIU/Gs and is two orders of magnitude higher than that of single-mode fiber which is confirmed by the theoretical calculation. It demonstrated that the EYDF has advantages and potential of high sensitivity, miniaturization, and easy integration for magnetic field detection in harsh environments.

Alkaline phosphatase (ALP) is an important enzyme-based biomarker present in several bacterial species; however, it is currently undervalued as a strategy to detect pathogenic bacteria. Here, we explore our ALP-responsive colorimetric and fluorescent probe (TCF-ALP) for such applications. TCF-ALP displayed a colorimetric and fluorescence response towards Staphylococcus aureus (S. aureus), with a limit of detection of 3.7 × 106 CFU mL−1 after 24 h incubation. To our surprise, TCF-ALP proved selective towards Staphylococcus bacteria when compared with Enterococcus faecalis (E. faecalis), and Gram-negative P. aeruginosa and E. coli. Selectivity was also seen in clinically relevant S. aureus biofilms. Owing to the high prevalence and surface location of S. aureus in chronic wounds, TCF-ALP was subsequently encapsulated in polyvinyl alcohol (PVA)-based hydrogels as a proof-of-concept “smart” wound dressing. TCF-ALP hydrogels were capable of detecting S. aureus in planktonic and biofilm assays, and displayed a clear colour change from yellow to purple after 24 h incubation using ex vivo porcine skin models. Overall, TCF-ALP is a simple tool that requires no prior knowledge, training, or specialist equipment, and has the potential to overcome issues related to invasive swabbing and tissue biopsy methods. Thus, TCF-ALP could be used as a tool to monitor the early development of infection in a wound and allow for the rapid provision of appropriate treatment for Staphylococcal bacterial infections.

Bio-triboelectric nanogenerators (bio-TENGs) have become one of the choices of energy supply for new electronic devices, but the relationship between the internal crystalline structure of bio-derived materials and the triboelectric performance has not been investigated. In this paper, microbial polyhydroxybutyrate (PHB) with special wrinkled spherulites is prepared by a high-pressure solid-state forming method, which unexpectedly facilitates the contact electrification of PHB. When the PHB-based TENG is stimulated, the intrinsic micro-/nanoscale dual crystalline structure of wrinkled spherulites enables significant improvement of the surface charge density of PHB. The open-circuit voltage and short-circuit current of the high-pressure crystallized PHB based TENG are around 5 and 12 times higher than those of the normal-pressure crystallized PHB-based TENG, respectively. Moreover, the bio-TENG shows remarkable stability and durability, and can be utilized as a reliable power source to drive commercial LEDs. In particular, the self-powered TENG sensor based on high-pressure crystallized PHB exhibits great prospects for monitoring and recognizing human athletic motions. This work shows that there is a simple but novel method to improve the performance of bio-TENGs, which not only determines the relationship between the crystalline structure of biomaterials and triboelectricity, but also provides a new insight for developing high-performance and environment-friendly electronic devices.

Understanding the limitations of electrocatalytic activity and developing advanced catalysts with enhanced activity are of exceptional importance for future hydrogen energy applications. Due to the complexity of electrolytic hydrogen evolution in alkaline media, there are limited non-noble metal catalysts to afford large scale applications. Tungsten-based catalysts exhibit favorable stability but relatively low activity owing to their strong H* adsorption characteristics. In this work, cobalt hydroxides/cubic phase WN nanoparticles with strengthened interfaces and adjustable nitrogen vacancies anchored on multi-walled carbon nanotubes (Co(OH)2/c-WN1−x/CNTs) are exploited as highly efficient alkaline hydrogen evolution electrocatalysts, which exhibit remarkable activity with an overpotential of 78 mV at 10 mA cm−2 and a low Tafel slope of 43 mV dec−1 in 1 M KOH media. Density-functional theory calculations revealed that the interfacial combinations of Co(OH)2/c-WN1−x were tuned to facilitate the kinetics of hydrogen evolution, where Co(OH)2 promoted the adsorption of water molecules and the H–OH dissociation, and cubic phase WN with nitrogen vacancies (c-WN1−x) accelerated hydrogen generation by optimizing the hydrogen adsorption free energy.

Nonnegligible emission of bioaerosols usually occurs during aeration of wastewater in aerator tanks in wastewater treatment plants (WWTPs). Literature had shown that the respiratory and intestinal diseases of workers at WWTPs are related to bioaerosols. Thus, quantitative microbial risk assessment (QMRA) based on Monte Carlo simulation was utilized in this research to assess the health risks of Gram-negative bacteria bioaerosol (GNBB) and Staphylococcus aureus bioaerosol (SAB) among academic visitors and staffs. Results showed that the concentrations of GNBB and SAB in the inverted umbrella aeration mode were consistently higher than those in the microporous aeration mode under all six size distribution ranges of the Anderson six-stage impactor. Thus, GNBB and SAB can be highly threatening to the weasand and first bronchus (or alveoli and third bronchus) for the exposure populations. The health risks (annual probability of infection (Py) and disease burden (DB)) of males were constantly higher than those of females for each certain exposure scenario. The health risks of staffs were higher than those of academic visitors when assessed by Monte Carlo simulation. The wearing of mask is an effective measure to minimize health risks through reducing the bioaerosol concentration intake. Especially, for the academic visitors and staffs exposed to GNBB, all their DB failed to meet the World Health Organization DB benchmark under various credible intervals when they were without a mask on. In a word, the results of health risk assessment in this research can be utilized as an educational tool and policy basis to facilitate the implementation of efficacious prevention measures to protect the public health from bioaerosol health threats in WWTPs.

As people pay more attention to the aesthetics of teeth, the adhesion of brackets in the orthodontic process received a wider application in recent years. In this paper, experiments and finite elem...

Replacement and regeneration of damaged bone, particularly for those defects with critical size, are still major challenges in orthopaedic surgery. The conventional bone implants, normally with poor internal architecture design, may cause significant issues owing to the mechanical and structural mismatches between target bone and the implants. In this work, as inspired by hierarchical natural bone, for the first time, we developed hydroxyapatite (HA) and beta-tricalcium phosphate (β-TCP) scaffolds with three-level hierarchical structures across macro to nano scale using combined 3D printing (3DP) and freeze casting routines. It is clear these hierarchical porous scaffolds significantly enhance cell penetration (over 7 times) while maintaining cell proliferation ability. With three levels of hierarchies, the overall mechanical behaviour of the scaffolds can be tailored to be comparable to general cancellous bone (ranging from 1 to 6 MPa), demonstrating great potential for practical applications. Additionally, the combination of nanoindentation and mechanics model makes it possible to predict the mechanical behaviour of scaffolds at micro and macro scales.

Stress is considered to be the inducer of microspore embyogenesis (ME), and heat stress is indispensible in the ME of sweet pepper. The aim of the study was to explore differentially expressed genes of microspore embryogenesis under heat stress in sweet pepper. The swollen rate of microspore was significantly affected by heat stress, while no green plant could be acquired without heat pretreatment. Anthers with or without heat stress were used for whole transcriptome analysis by RNA sequencing to provide new insights on how cells adapt to stress. A total of 5031 differentially expressed genes were identified, among which 2657 differentially expressed genes were up-regulated and 2374 differentially expressed genes were down-regulated in the early stage of heat stress. KEGG pathway analysis identified "plant hormone signal transduction" (67; 11.20%), followed by starch and sucrose metabolism (63; 10.54%). RNA-Seq data and quantitative real-time polymerase chain reaction showed that 224 genes related to glutathione metabolism, starch and sucrose metabolism, plant hormone signal transduction and phenylpropanoid biosynthesis were the most likely specific genes in ME under heat stress. This research provides new insights into molecular regulation during the early stage of ME in sweet pepper under heat stress. Key words: Differentially expressed genes, heat stress, microspore embryogenesis, sweet pepper

In order to restore the vegetation of forests, China has implemented the project of restoring the farmland to the forest. With the advancement of this project, the artificial vegetation restoration area adjacent to the forest is expanding. In this study, a secondary oak forest, its adjacent restored poplar forest and the secondary oak forest-restored forest ecotone were selected as the study sample plots, and the ground-dwelling beetle community was investigated by pitfall trap method for exploring the diversity characteristics of the ground-dwelling beetle community in this complex ecosystem, in order to reveal the relationship between the ground-dwelling beetle and the environmental changes. In this study, 2458 ground-dwelling beetles belonging to 94 species of 24 families were collected from the secondary oak forest and its adjacent restored poplar forest from April to September 2017, of which Scarabaeidae, Carabidae and Silphidae were the dominant communities of ground-dwelling beetles in the sample plots. The order of the species number and individuals number of ground-dwelling beetles in the different types of vegetation was the secondary oak forest > ecotone > restored poplar forest in turn, with significant differences. The estimation of nonparametric species richness showed that the sampling intensity was not fully saturated, indicating that more surface beetle species could be collected. The Margalef richness index, Simpson diversity index (λ), Hill diversity index (N2), Pielou evenness index (E1), Hill evenness index (E2) and modified Hill evenness index (EHill) of surface beetles were significantly different in the different habitats, and higher diversity and evenness of the surface beetles were maintained in the restored poplar forest, indicating that the restoration and re-naturalization of forest vegetation could increase the insect species and community stability. The community similarity analysis indicated that the ground-dwelling beetle community among the secondary oak forest, the ecotone and the restored poplar forest was at the middle level of dissimilarity. The edge effect intensity analysis suggested that there was a negative edge effect in the ecotone between the secondary oak forest and the restored poplar forest.

Silicon dioxide (SiO2) has great potential application as anode materials for lithium-ion battery owing to the rich resource, economic cost, and easy preparation. SiO2/Ti3C2 (ST-1, ST-2, and ST-3, respectively) nano-/microcomposites were synthesized via three different methods (sol-gel, centrifugal-drying, and freeze-drying method), and the SEM results indicate that abundant SiO2 particles are distributed on the modified surface of multilayer Ti3C2 nanosheets, forming stable multiphase structures. Electrochemical results demonstrate that the SiO2/Ti3C2 composites can deliver good electrochemical performance and almost have no capacities decay after hundreds of cycles. In particular, the structure properties of ST-3 composite synthesized by freeze-drying were well preserved, delivering a reversible discharge capacity of 242.4 mAh g−1 at 100 mA g−1, even after high-rate test (5000 mA g−1), still exerting 258.6 mAh g−1 reversible discharge capacity at 100 mA g−1, indicating good structural stability and electrochemical reversibility of ST-3 composite for lithium-ion batteries.

To understand the molecular and physiological mechanism underlying the heat stress in maize, transcriptional and physiological response to heat stress in the heat-resistant Huangzaosi (HZS) and heat-sensitive Lv-9-Kuan (L9K) inbred lines at seedling stage were analyzed and compared at seedling stage. Our results indicated that MDA content of the two inbred lines increased significantly under heat stress; the values of MDA in L9K was significantly higher than that in HZS. The level of SOD, CAT, and POD enzyme activities in HZS was higher than those in L9K for both the heat-treated group and controls. The values of Fv/Fm, qP, and ФPSII reduced by heat stress in L9K were higher than the respective values in HZS. RNA-seq data showed that heat stress induced more heat stress-related genes in HZS (257 heat stress-related genes) than in L9K (224 heat stress-related genes). GO and KEGG enrichment analyses indicated that HZS and L9K changed their physiological and biochemical mechanisms in response to heat stress through different molecular mechanisms. Weighted Gene Co-expression Network Analysis showed that HZS might obtain stronger heat resistance than L9K through a unique transcriptional regulatory network. Our findings provide insights into the molecular networks that mediate the tolerance of maize heat stress and also help us to mine key heat stress-related genes.

Ferromagnetic-dielectric nanocomposites have attracted extensive interests for its high electromagnetic wave absorption (EMA) performance due to the synergetic effects between different components. Herein, we report the design of core–shell structured Co7Fe3@TiO2 composite particles, which are subsequently annealed in H2/Ar atmosphere to further improve its EMA performance. The introducing of TiO2 dielectric shell together with hydrogen annealing contributes greatly to the electromagnetic properties due to the increased conductivity and enhanced ferromagnetic resonance. Excellent EMA performance is achieved in S (2–4 GHz) and C (4–8 GHz) bands in coatings using Co7Fe3@TiO2 as absorbents. Apart from the high EMA efficiency, the location of EMA band can be tailored in a wide range through regulating the coating thickness. Specifically, an effective absorption band of 2.0 GHz in C band at a thickness of 2.62 mm, and an effective absorption band of 1.7 GHz are achieved in S band at thicknesses of 4.0–5.0 mm. The excellent electromagnetic properties are ascribed to the effective complementary between dielectric loss and ferromagnetic loss.

Let $${\mathcal {M}}$$ be a diffuse von Neumann algebra with a faithful normal semi-finite trace $$\tau $$ , and let E be a symmetric quasi-Banach space. Then for any Orlicz function $$\varphi $$ , we can define the noncommutative Calderon–Lozanovskiĭ spaces $$E_\varphi ({\mathcal {M}})$$ . These spaces share many properties with their classical counterparts. In particular, new multiplication operator spaces and complex interpolation spaces of such spaces are given under a wide range of conditions. Moreover, letting $${\mathcal {A}}$$ be a maximal subdiagonal algebra of $${\mathcal {M}}$$ , we introduce the noncommutative Calderon–Lozanovskiĭ–Hardy spaces $$H^\varphi ({\mathcal {A}})$$ and transfer the recent results of the noncommutative Hardy spaces to the noncommutative Calderon–Lozanovskiĭ–Hardy spaces.

The present work investigated the effect of weld composition and welding heat input on the microstructure and mechanical properties of two submerged arc welded (SAW) joints of API 5L-X80 pipeline steel. The weld metals were joined by two welding consumables (one is rich in C, Ni, Cr, Mo) under different welding heat inputs (20-22 and 34-36 kJ/cm for single-wire and triple-wire processes, respectively). The triple-wire welding procedure with less C, Ni, Cr, Mo alloy contents favors the formation of acicular ferrite (AF), whereas single-wire welding procedure with increased C, Ni, Cr, Mo contents promotes the formation of lath bainite (LB). Nanoindentation is used to evaluate the property of different microstructures. The hardness of lath bainite (LB), granular bainite (GB) and acicular ferrite (AF) is 8.0 GPa, 5.8 GPa and 3.0 GPa, respectively. The Charpy impact energy of weld metal with triple-wire welding procedure (136-165 J) is much greater than that with single-wire welding procedure (15-44 J) at − 45 °C. Larger cleavage facet size is observed in the fracture surface of single-wire weld metal. A computational procedure is developed to understand the temperature fields during the triple-wire welding. Combining the experiments and numerical simulation, simple models to predict the microstructure evolution through the weld thickness are established.

The optimization of microwave absorption is closely bound up with the of controllable strucuture of absorber materials. Hierarchically porous carbon (HPC) with two level pore structure has thriving as promising candidates for high performance microwave absorption application. However, fabricating HPC with tunable porous structure in a facile and sustainable manner with high yield is still a challenge for vast use in efficient electromagnetic (EM) wave absorption systems. Herein, a series of hierarchical porous carbon materials with different pore structures were synthesized from wheat flour dough through a facile biomass fermentation method. By gradually increasing the fermentation time, the conchoidal cavities gradually evolved to microscale macropore channels, and the number and size of pore increased synchronously. Microwave absorption studies revealed that the formation of macropore channels led to an apparent enhancement of dielectric properties, which can be further increased with the porosity increasing. Consequently, a strong absorption intensity of −52.0 dB at 2.50 mm and a broad microwave absorption bandwidth of 4.6 GHz at only 1.55 mm were achieved. Excellent microwave absorption performance can be ascribed to the improvement in dielectric loss. This approach shed the insights on achieving low-cost, green and industrial-scale production of EM absorber from renewable biomass.

Oxygen-anion redox in lithium-rich layered oxides can boost the capacity of lithium-ion battery cathodes. However, the over-oxidation of oxygen at highly charged states aggravates irreversible structure changes and deteriorates cycle performance. Here, we investigate the mechanism of surface degradation caused by oxygen oxidation and the kinetics of surface reconstruction. Considering Li2MnO3, we show through density functional theory calculations that a high energy orbital (lO2p’) at under-coordinated surface oxygen prefers over-oxidation over bulk oxygen, and that surface oxygen release is then kinetically favored during charging. We use a simple strategy of turning under-coordinated surface oxygen into polyanionic (SO4)2−, and show that these groups stabilize the surface of Li2MnO3 by depressing gas release and side reactions with the electrolyte. Experimental validation on Li1.2Ni0.2Mn0.6O2 shows that sulfur deposition enhances stability of the cathode with 99.0% capacity remaining (194 mA h g−1) after 100 cycles at 1 C. Our work reveals a promising surface treatment to address the instability of highly charged layered cathode materials., Oxygen-anion redox in lithium-rich layered oxides can boost the capacity of lithium-ion battery cathodes. Here, the authors investigate the mechanism of surface degradation caused by oxygen oxidation and the kinetics of surface reconstruction.

Lateral hetero-junctions are considered as potential candidate for building blocks in modern electronics and optoelectronics, however, the construction of which remains a challenge. In this work, by using a laser-assisted manufacture technique, WSe2/WO3−x hetero-junction and monolayer/trilayer WSe2 homo-junction with Schottky diode like behavior are fabricated, both of which present competitive performance for photodetection and power generation in a wide range of wavelengths from ultraviolet to infrared, with maximum photoresponsivity of 10 A/W, external quantum efficiency of 14%, and power conversion efficiency of 1.3%. Combined with Kelvin probe microscopy and electrical transport measurements, it is demonstrated that the barrier-induced built-in electric field at WSe2/WO3−x interface, and the energy band discontinuities at the monolayer/trilayer WSe2 interface facilitate the separation of photo-generated electron-hole pairs. Our work provides a solid step towards the controllable construction of lateral junctions by laser-assisted manufacture for exploiting van der Waals materials-based novel electronic and optoelectronic applications.

In situ TiC particles-reinforced FeCrNiCu high-entropy alloy matrix composites were prepared by vacuum induction melting method. The reaction mechanisms of the mixed powder (Ti, Cu and C) were analyzed, and the mechanical properties of resultant composites were determined. Cu4Ti were formed in the reaction of Cu and Ti when the temperature rose to 1160 K. With the temperature further increased to 1182 K, newly formed Cu4Ti reacted with C to give rise to TiC particles as reinforcement agents. The apparent activation energy for these two reactions was calculated to be 578.7 kJ/mol and 1443.2 kJ/mol, respectively. The hardness, tensile yield strength and ultimate tensile strength of the 15 vol% TiC/FeCrNiCu composite are 797.3 HV, 605.1 MPa and 769.2 MPa, respectively, representing an increase by 126.9%, 65.9% and 36.0% as compared to the FeCrNiCu high-entropy base alloy at room temperature. However, the elongation-to-failure is reduced from 21.5 to 6.1% with the formation of TiC particles. It was revealed that Orowan mechanism, dislocation strengthening and load-bearing effect are key factors responsible for a marked increase in the hardness and strength of the high-entropy alloy matrix composites.

Binders have an important function in the performance of Li-ion batteries even though they are only used in small quantities. In addition to poor adhesion properties, the traditional polyvinylidene difluoride binder raises many environmental and health concerns because of their processing that involves hazardous organic solvents. In this study, we introduced a water-soluble, environmentally friendly tapioca starch binder modified with polyethylene glycol (PEG) groups as a novel binder for Si anode electrodes in Li-ion batteries. The experiments and density functional theory simulations indicate that abundant hydroxyl groups in the starch improve the binding strength with Si nanoparticles, and the integrated PEG groups facilitate Li-ion transfer in the Si electrode. The mechanical behavior of the electrode is significantly improved, as confirmed by nanoindentation and scratch tests. Excellent electrochemical performance is observed, with an initial lithiation capacity of 3486 mA h g-1 and a noteworthy second cycle capacity retention of 98%, demonstrating its potential as a cheap and sustainable binder for Li-ion batteries.

Water shortages and pollution emerge because of anthropogenic demands. Since 2011, ‘China's Most Stringent Water Resources Management’ (CMSWRM) has been comprehensively enacted in the country. This paper presents the characteristics of the ‘three red lines’ (TRL) and a multi-objective optimal allocation model based on the TRL constraint, considering the benefits for society, the economy, and the environment. This model had been applied to the reasonable allocation of water supply and demand in Qinzhou for the planning years of 2020 and 2030. Two water resource allocation scenarios for these years were configured by setting different chemical oxygen demand (COD) concentrations for wastewater discharge in the municipal, secondary, tertiary, and agricultural sectors. The gamultiobj function based on the NSGA-II algorithm was used to solve the model in MATLAB. The results indicate that if COD concentrations in each sector are not reduced, then restrictions on domestic water sources will be necessary, both in 2020 and 2030. The two water resource allocation scenarios in 2020 and 2030 can provide a reference for decision-makers in Qinzhou to implement CMSWRM.

Silicon (Si) anodes suffer from severe structural instability caused by volume expansion during lithium insertion and extraction. The extensive stress generated causes delamination at the anode/current collector interface and early capacity decay. We developed a novel anode structure by introducing a liquid metal layer in between Si and the Cu current collector. Both experiments and the density functional theory (DFT) simulation indicate an increased flexibility in the hybrid structure. No visible cracking or interface delamination was observed, attributed to the self-healing effect from the liquid metal. This work introduces a novel design for hybrid anodes with balanced mechanical strength and electrochemical performance.

Mesoporous carbon hollow sphere (MCHS) is one of the most significant functional materials in various fields. Unfortunately, systematically regulating microstructure of MHCS has been rarely investigated so far. In this work, using one unique simultaneous-hydrolyzation-polymerization process, we are able to precisely control the morphology configurations of MCHS, including its shell thickness and integrate size, hollow void and mesopore in the shell. The shell thickness and integrate size are associated with the synergistic effect of hydrolyzation and polymerization reactions. The hollow void and mesopore are determined by the SiO2 template morphology. Thus, a series of MCHSs with controlled microstructure were achieved through elaborately tuning the precursor. More importantly, different types of MCHSs demonstrate significantly different dielectric and microwave absorbing properties due to the discrepancy of volume ratio between pores and carbon compositions. The typical sample could achieve a broad effective absorption bandwidth of 5.9 GHz and 6.5 GHz with a thickness of 2.35 mm and 2.65 mm, respectively, at a filling ratio of only 20 wt%. These encouraging results significantly promote a deeper understanding of the fundamental chemistry mechanism for constructing MCHS as well as using the material as potential candidate for solving microwave interference issue.

We have successfully developed a Mg–3Al–0.4Mn (wt%) alloy sheet with good room-temperature formability. The alloy sheet shows a large Index Erichsen value of 8.2 mm due to its unique texture feature where the most of the grains have circular distribution of basal poles away from the normal direction of the sheet. The fine grain structure also leads to moderate strengths and large ductility with in-plane isotropic tensile property. These mechanical properties could be realized via industry viable rolling processing, thus the alloy sheet is highly possible to broaden the applications of Mg alloys in automotive industries.

Nacre like graphene based composite films (GCFs) have been developed over the last decade. Although the progress in ultrastrong GCFs is remarkable, fabricating GCFs with excellent integrated properties of strength, flexibility, and toughness still remains a challenge. Here, a ternary GCF of reduced graphene oxide (rGO), polydopamine (PDA) and multi-walled carbon nanotubes (MWCNTs) was developed. The MWCNTs were modified by PDA to form PDA@MWCNTs which were then compounded with GO to fabricate the rGO-PDA@MWCNT films by evaporation-induced assembly and chemical reduction. The preparation was simple, cheap and environmentally-friendly. The PDA increased the dispersion of MWCNTs in the rGO-PDA@MWCNT films, crosslinked the rGO sheets, and enhanced the entanglement of MWCNTs and the interactions between MWCNTs and rGO sheets. Benefiting from the synergistic effect of PDA and MWCNTs, the rGO-PDA@MWCNT films exhibited excellent integrated properties by increasing strength, tensile fracture strain and toughness to 579 ± 35 MPa, 12.03 ± 0.56%, and 34.03 ± 1.60 MJ/m3, which were 2.26, 2.02 and 4.94 times that of pure rGO films, respectively. The rGO-PDA@MWCNT films also exhibited a high conductivity of 612 ± 68 S/cm and excellent structural stability under extreme environments. These excellent integrated properties of the rGO-PDA@MWCNT films will promote their applications in aerospace engineering, flexible electrical devices and artificial muscle.

In this work, a latent energy-transfer process in traditional Eu3+ ,Tb3+ -doped phosphors is proposed and a new class of Eu3+ ,Tb3+ -doped Na4 CaSi3 O9 (NCSO) phosphors is presented which is enabled by luminescence decay dynamics that optimize the electron-transfer energy process. Relative to other Eu3+ ,Tb3+ -doped phosphors, the as-synthesized Eu3+ ,Tb3+ -doped NCSO phosphors show improved large-scale tunable emission color from green to red upon UV excitation, controlled by the Tb3+ /Eu3+ doping ratio. Detailed spectroscopic measurements in the vacuum ultraviolet (VUV)/UV/Vis region were used to determine the Eu3+ -O2- charge-transfer energy, 4f-5d transition energies, and the energies of 4f excited multiplets of Eu3+ and Tb3+ with different 4fN electronic configurations. The Tb3+ →Eu3+ energy-transfer pathway in the co-doped sample was systematically investigated, by employing luminescence decay dynamics analysis to elucidate the relevant energy-transfer mechanism in combination with the appropriate model simulation. To demonstrate their application potential, a prototype white-light-emitting diode (WLED) device was successfully fabricated by using the yellow luminescence NCSO:0.03Tb3+ , 0.05Eu3+ phosphor with high thermal stability and a BaMgAl10 O17 :Eu2+ phosphor in combination with a near-UV chip. These findings open up a new avenue to realize and develop multifunctional high-performance phosphors by manipulating the energy-transfer process for practical applications.

Rich chemistry and surface functionalization provide MXenes enhanced electrochemical activity yet severely exacerbate their self-discharge behavior in supercapacitors. However, this self-discharge behavior and its related mechanism are still remaining issues. Herein, we propose a chemically interface-tailored regulation strategy to successfully unravel and efficiently alleviate the self-discharge behavior of Ti3C2Tx MXene-based supercapacitors. As a result, Ti3C2Tx MXenes with fewer F elements (∼0.65 atom %) show a positive self-discharge rate decline of ∼20% in comparison with MXenes with higher F elements (∼8.09 atom %). Such decline of the F elements can highly increase tight-bonding ions corresponding to an individual self-discharge process, naturally resulting in a dramatic 50% increase of the transition potential (VT). Therefore, the mixed self-discharge rate from both tight-bonding (contain fewer F elements) and loose-bonding ions (contain more F elements) is accordingly lowered. Through chemically interface-tailored engineering, the significantly changed average oxidation state and local coordination information on MXene affected the interaction of ion counterparts, which was evidently revealed by X-ray absorption fine structures. Theoretically, this greatly improved self-discharge performance was proven to be from higher adsorption energy between the interface of the electrode and the electrolyte by density functional theory. Therefore, this chemically interface-tailored regulation strategy can guide the design of high-performance MXene-based supercapacitors with low self-discharge behavior and will promote its wider commercial applications.

Sodium-ion batteries (SIBs) have emerged as a promising alternative to Lithium-ion batteries (LIBs) for energy storage applications, due to abundant sodium resources, low cost, and similar electrochemical performance. However, the large radius of Na+ and high molar mass compared to Li+, result in large volume strain during charge/discharge and low reversible capacity and poor cycling stability. Due to exceptional physical and chemical properties, graphene has attracted increasing attention as a potential anode material for SIBs. When integrated with other nanomaterials in electrodes, graphene can improve the electrical conductivity, accommodate the large volume change and enhance reaction kinetics. This paper provides a systematic review of recent progress in the application of graphene based anodes for SIBs, with a focus on preparation, structural configuration, Na+ storage mechanism and electrochemical performance. Additionally, some challenges and future perspectives are provided to improve the sodium storage performance of graphene based electrodes.

The brittleness index (BI) is an important parameter for coal-bed methane (CBM) reservoir fracturing characterization. Most published studies have relied on petrophysical and well-log data to estimate the geomechanical properties of reservoir rocks. The major drawback of such methods is the lack of control away from well locations. Therefore, we have developed a method of combining BI calculation from well logs with that inverted from 3D seismic data to overcome the limitation. A real example is given here to indicate the workflow. A traditional amplitude-variation-with-offset (AVO) inversion was conducted first. BI for the CBM reservoir was then calculated from the Lamé constants inverted from prestack seismic data through a traditional AVO inversion method. We build an initial low-frequency model based on the well-log data. Comparison of the seismic inverted BI at the target reservoir and BI extracted from the well-log data showed satisfactory results. This method has been proved to be efficient and effective enough at identifying BI sweet spots in CBM reservoirs.

Cancer is among the leading causes of death worldwide. Although a number of new treatment options have been developed in recent years, there remains a need for improved chemotherapies. The primary challenges facing new cancer drugs include: (1) improving patient quality of life, (2) overcoming drug resistance and (3) lowering reoccurrence rates. Major drawbacks of current chemotherapeutics arise from poor selectivity towards cancer cells, dose limiting toxicities, compliance-reducing side effects, and an inability to address resistance mechanisms. Chemotherapeutics that fail to achieve complete eradication of the disease can also lead to relapse and promote treatment resistance. New strategies to overcome these drawbacks include the use of transition metal chelators and ionophores to alter selectively the concentrations of iron, copper, and zinc in cancer cells. A number of metal chelators have successfully demonstrated cytotoxicity and targeted activity against drug-resistant cancer cells; several have proved effective against cancer stem cells, a significant cause of tumour reoccurrence. However, problems with formulation and targeting have been noted. Recent efforts have thus focused on the design of pro-chelators, inactive versions of chelators that are designed to be activated in the tumour. This is an appealing strategy that may potentially increase efficacy towards cancer-resistant malignant cells. This Tutorial Review summarizes recent progress involving transition metal chelators, pro-chelators, and ionophores as potential cancer chemotherapeutics. We will focus on the reported agents that are able to coordinate iron, copper, and zinc.