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Zenghou Yi Tomb (433 BC) in the early Warring States Period of China is a very important archaeological discovery. Lots of lacquerware was unearthed here, typically representative of that from Chu in the Warring States Period. This article presents analyses of the lacquered inner coffin and a lacquered zither from the tomb, and their surface is red lacquer, supplemented by additional black and yellow patterns. Yellow painted lacquerware remains relatively rare from this period and therefore deserves further study. Numerous methods including three-dimensional (3D) video microscopy and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), pyrolysis-gas chromatography/mass spectroscopy (Py-GC/MS), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy as well as enzyme-linked immunoassay (ELISA) were adopted to analyze the lacquer and pigments from the two artifacts. The results of this study reveal that lacquer samples from both the two artifacts have multilayered structures and contained added eggs and oil. The red pigment on the lacquer surface was made of cinnabar mixed with lacquer, the black one was carbon black mixed with lacquer, while the yellow one was pararealgar mixed with gelatin. These differences may explain the relative rarity of yellow painted lacquerware from early periods.

It is known that exposed surface determines material’s performance. WO3 is widely used in gas sensing and its working surface is proposed to control its sensitivity. However, the working surface, or most exposed surface with detailed surface structure remain unclear. In this paper, DFT calculation confirmed that oxygen vacancy O-terminated surface is the most exposed hexagonal WO3 (001) surface, judging from competitive adsorption of CO and O2, working surface determination for CO sensing and comparison of oxygen vacancy formation energies on different h-WO3 (001) surfaces. It is found that DFT can be a useful alternate for exposed surface determination. Our results provide new perspectives and performance explanations for material research.

A typical diachronous breakup developed in the South China Sea (SCS); the breakup has been unequivocally identified, and gradually decreases in age from NE to SW. To illustrate the influence of a d...

Achievable information rates of optical communication systems are inherently limited by nonlinear distortions due to the Kerr effect occurred in optical fibres. These nonlinear impairments become more significant for communication systems with larger transmission bandwidths, closer channel spacing and higher-order modulation formats. In this paper, the efficacy of nonlinearity compensation techniques, including both digital back-propagation and optical phase conjugation, for enhancing achievable information rates in lumped EDFA- and distributed Raman-amplified fully-loaded C −band systems is investigated considering practical transceiver limitations. The performance of multiple modulation formats, such as dual-polarisation quadrature phase shift keying (DP-QPSK), dual-polarisation 16 −ary quadrature amplitude modulation (DP-16QAM), DP-64QAM and DP-256QAM, has been studied in C −band systems with different transmission distances. It is found that the capabilities of both nonlinearity compensation techniques for enhancing achievable information rates strongly depend on signal modulation formats as well as target transmission distances.

The oral cavity harbors complex microbial communities, which leads to biomaterial-associated infections (BAI) during dental and orthopedic treatments. Conventional antibiotic treatments have met great challenges recently due to the increasing emergency of drug-resistant bacteria. To tackle this clinical issue, antibacterial surface treatments, containing surface modification and coatings, of dental and orthopedic materials have become an area of intensive interest now. Among various antibacterial agents used in surface treatments, metallic agents possess unique properties, mainly including broad-spectrum antibacterial properties, low potential to develop bacterial resistance, relative biocompatibility, and chemical stability. Therefore, this review mainly focuses on underlying antibacterial applications and the mechanisms of metallic agents in dentistry and orthopedics. An overview of the present review indicates that much work remains to be done to deepen the understanding of antibacterial mechanisms and potential side-effects of metallic agents.

Background: The initial outbreak of COVID-19 caused by SARS-CoV-2 in China in 2019 has been severely tested in other countries worldwide. To address the challenges posed by COVID-19, the links among the transmission of COVID-19, socio-economic factors and climatic factors must be understood to suggest better strategies for predicting, preventing, coping with and mitigating the associated challenges. We aimed to describe the spatial distribution of the COVID-19 pandemic worldwide and assess the effects of various socio-ecological factors, including climate and socio-economic factors, on COVID-19 risk. Methods: We collected COVID-19 pandemic infection data of 178 countries/regions worldwide from the 2019 Novel Coronavirus Visual Dashboard data repository, operated by the Johns Hopkins University Center for Systems Science and Engineering (JHU-CSSE), and collected socio-ecological data from the Global Surface Summary of the Day (GSOD) and World Development Indicators dataset. We established the Potential Risk Assessment Framework for COVID-19. We used spatial econometrics method to assess the global and local correlation of COVID-19 risk indicators (the incidence rate, cumulative mortality rate and daily cumulative index) for COVID-19. To estimate the adjusted IRR, we modelled negative binomial regression analysis with spatial information and socio-ecological factors. Findings: By April 6, 2020, 178 cases were reported globally. The test results for local spatial correlations indicated that 37, 29 and 39 countries/regions were strongly opposite from the IR, CMR and DCI index "spatial autocorrelation hypothesis", respectively. The IRs were significantly positively associated with GDP per capita, the use of at least basic sanitation services and social insurance program coverage, and were significantly negatively associated with the proportion of the population spending more than 25% of household consumption or income on out-of-pocket health care expenses and the poverty headcount ratio at the national poverty lines. The CMR was significantly positively associated with urban populations, GDP per capita and current health expenditure, and was significantly negatively associated with the number of hospital beds, number of nurses and midwives, and poverty headcount ratio at the national poverty lines. The DCI was significantly positively associated with urban populations, population density and researchers in R&D, and was significantly negatively associated with the number of hospital beds, number of nurses and midwives and poverty headcount ratio at the national poverty lines. We also found that climatic factors (temperature, relative humidity, precipitation and wind speed) did not significantly reduce COVID-19 risk.I nterpretation: Attention must be paid to the similarities in COVID-19 transmission characteristics (such as transmission speed and mortality rate) across countries/regions, and national/regional early warning and protection measures must be successfully implemented. Governmental regulation of social and economic factors is particularly important to reduce COVID-19 risk. To fight against COVID-19 more effectively, countries/regions should pay more attention to controlling population flow, improving diagnosis and treatment capacity, and improving public welfare policies. Funding Statement: National Natural Science Foundation of China, Michigan Institute for Clinical and Health Research. Declaration of Interests: DS, YC, MT and YZ are funded by National Natural Science Foundation of China (No. 71473096; No. 71673101; No. 71974066). YZ is funded by Michigan Institute for Clinical and Health Research (MICHR No. UL1TR002240). All other authors declare no competing interests.

This study researches an improved scheme of membership function optimisation (MFO) for fuzzy air–fuel ratio (AFR) control of gasoline direct injection (GDI) engines based on correspondence analysis (CA). This proportional–integral-like fuzzy knowledge-based controller (FKBC) optimised by the proposed scheme can further optimise AFR control performance while maximising conversion efficiency of the three-way catalyst to eliminate the exhaust emissions in real time. Different from the conventional experience-based membership function (MF) design method for an FKBC, the proposed MFO scheme uses CA approach and can visualise the relationship between engine step gain scenarios and designed MF patterns to precisely determine its scalar parameters for AFR regulation of GDI engines. Within this context: (i) specialised MFs for self-adaptive AFR control system of a GDI engine are designed with weight distribution; (ii) based on designed scalar parameters, the CA model with taxonomic dimensions is built for acquiring a customised MF to counter transient scenario changes more effectively; (iii) the engine controller with the proposed scheme is real time validated in a production V6 GDI engine, and its advantage in terms of engine transient control performance is further demonstrated by comparing with a benchmark controller designed based on experience.

Toroid-shaped Fe-based soft magnetic amorphous powder cores were prepared from Fe76Si9B10P5 (at.%) amorphous powder by gas atomization and subsequent cold pressing with epoxy resin as a binder and insulation. The influence of epoxy resin content and annealing temperature on the magnetic properties of the amorphous soft magnetic powder cores were analyzed. The core loss at a frequency of 100 kHz for the samples with 2 wt% epoxy resin and annealed at 480 °C for 1 h is evaluated to be less than 800 mW/cm3 under a maximum induction of 100 mT. Meanwhile, the cores also exhibit high permeability of 86 at a frequency up to 20 MHz. These results suggest that Fe-based amorphous powder cores provide great potential for expanding the application of high frequency electronic elements used in rectifiers, inverters, transformers and inductance, which requires soft magnetic cores with high saturation magnetization, high permeability, and low core loss.

Divanillic acid (DVA)–based monomers with different side-chains (R = -(CH2)n-1-CH3, n = 1, 4, 8) were synthesized from methyl vanillate. Polycondensation of these monomers with various aromatic diamines yielded a series of aromatic biomass-based polyamides with weight-average molecular weights (Mw) ranging from 50,000 to 110,000 g/mol. Thermogravimetric analysis (TGA) of the polyamides found decomposition temperatures ranging from 378 to 420 °C. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) revealed an amorphous structure. The polyamides with methyl or butyl side chains exhibited a glass transition temperature (Tg) of 221–322 °C, which indicated high heat resistance and thermal stability, while the Tgs of the polyamides with octyl side chains were about 180 °C. The DVA polyamides showed good solubility in common polar organic solvents; their cast films were prepared from dimethylformamide (DMF) solution. Thermo-pressed films of some polyamides were prepared at temperatures over the Tg, revealing maximum tensile strengths of about 63 MPa.

A new and simple method was established to prepare polyamides with a chelating feature through Michael addition and polycondensation. A piperazine-diester monomer, that is, N,N´-bis(methyl propanoate) piperazine (BMPZ), was synthesized through a Michael addition of piperazine and methyl acrylate. Three polyamides containing piperazine rings (PIP-PAs) were synthesized via melt polycondensation from BMPZ and different diamines. PIP-PAs were modified by chelating Co2+, and several PIP-PA-Co2+ complexes were obtained. The structure of BMPZ and PIP-PAs was characterized by FT-IR and 1H NMR spectra. DSC and wide angle X-ray diffraction verified the crystallizable feature of PIP-PAs. They possessed Tm from 81 °C to 171 °C, tensile strength up to 31 MPa, and good toughness. Chelating PIP-PAs with Co2+ was accompanied by color change and the loss of crystallization. The effect of chelation on Tg, tensile strength, and Young's modulus was investigated. Polyamide complexes with good mechanical property and solvatochromic feature were synthesized successfully.

In this paper, we demonstrated ytterbium-doped mode-locked fiber lasers based on saturable absorbers (SAs) made of few-layer black phosphorus (BP) with all normal dispersion. The few-layer BP was prepared with the liquid phase exfoliation method and was deposited onto fiber facets by an optically driven process. By incorporating the BP-SA into an ytterbium-doped fiber cavity, stable mode-locking laser operation in all-normal dispersion region was achieved with a repetition rate of 46.3 MHz. The laser spectrum was centered at 1030.6 nm with a 3 dB bandwidth of 0.11 nm. Maximum output power of 32.5 mW was achieved and showing no signs of saturation.

Bone defects, massive bone defects in particular, is still an issue clinically. Acetylsalicylic acid (ASA), also known as aspirin, has been proven to be conducive for mesenchymal stem cells osteogenic differentiation, which may be benefited for bone regeneration. In order to achieve a more appealing prognosis of bone defect, here we develop a well-defined tetra-PEG hydrogel sealant with rapid gelation speed, strong tissue adhesion, and high mechanical strength. After in-situ encapsulation of aspirin, this drug-loaded tetra-PEG hydrogel possessed a sustained release, anti-inflammation, and osteoinductive properties. In vitro experiments showed that the cell proliferation was slightly facilitated, and the osteogenic differentiation was notably augmented when periodontal ligament stem cells (PDLSCs) were co-incubating with the hydrogel materials. Moreover, in vivo study manifested that the aspirin sustained release system significantly facilitated the PDLSCs mediated bone defect regeneration. Overall, tetra-PEG hydrogel-based aspirin sustained release system is applicable not only for enhancing the osteogenesis capacity of PDLSC but also providing a new thought of bone regenerative therapy.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) hold great promise for room temperature (RT) NO2 sensors. However, the exposure of the edges of TMDs with high adsorption capability and electronic activity remains a great obstacle to achieve high sensor sensitivity. Herein, we demonstrate a high-performance RT NO2 gas sensor based on WS2 nanosheets/carbon nanofibers (CNFs) composite with abundant intentionally exposed WS2 edges. Few-layer WS2 nanosheets are anchored on CNFs through a hydrothermal process. The approach permits to achieve a coating presenting an optimized active surface area and accessibility of the sensing layers. The exposure of WS2 edges remarkably improves the sensing properties. Consequently, the WS2@CNFs composite exhibits excellent selectivity to NO2 at RT with improved response and much lower detection limit in comparison to the WS2 and CNFs counterparts. Density functional theory (DFT) calculations verify a surprisingly strong NO2 adsorption on WS2 edge sites (adsorption energy 3.40 eV) with a partial charge transfer of 0.394e, while a week adsorption on the basal surface of WS2 (adsorption energy 0.25 eV) with a partial charge transfer of 0.171e. The strategy proposed herein will be instructive to the design of efficient material structures for low-power NO2 sensors with optimized performances.

This work synthesized a series of symmetrical methylated dialkoxydivanillic acid monomers (Me-RDVAs) with different side-chain lengths (meaning the number of carbons, n, in alkoxy groups, where n = 1, 2, 3 or 4) and methyl (Me), ethyl, propyl or butyl R groups. Homopolyesters were obtained from Me-RDVAs and 1,4-benzenedimethanol, 1,4-cyclohexanedimethanol and 4,4ʹ-biphenyldimethanol, with the aim of producing improved thermal properties. Copolyesters composed of Me-MeDVA together with aliphatic linear diols and cyclic diols were also synthesized. The weight average molecular weights of the resulting polyesters ranged from 1.5 to 11.0 × 104 g/mol and all were thermally stable. Glass transition temperatures varied from 58 to 134 °C. A semi-crystalline polyester with a high melting point of 220 °C was obtained from Me-MeDVA and trans-1,4-cyclohexanedimethanol, and was assessed using polarized optical microscopy and one-dimensional wide-angle X-ray diffraction. Self-standing films of several high molecular weight polyesters were prepared and their mechanical properties assessed.

Groundwater on remote coral atoll islands in tropical oceans occurs in the form of freshwater groundwater lenses (FGLs) that serve as an important water resource for local inhabitants and ecosystems. Continuous recharge of freshwater from rainfall can flush out salt water and eventually create a FGL beneath the natural or reclaimed island. However, the process whereby a FGL grows in reclaimed islands, and the dynamic mechanisms and formation process are unclear. This study used numerical modeling for a reclaimed island in the South China Sea to evaluate the process of mixing between freshwater and saltwater, dynamic mechanisms, and the formation process of FGLs influenced by tidal action. Our results revealed that the long-term average flow lines of FGLs were superimposed by short-term tidal fluctuations beneath the atoll island. The tidal signals move rapidly inland from the lower aquifer and are then propagated upwards to drive the water level in the Holocene sediments. This causes an oscillation of the FGLs and increased mixing between salt and fresh water. The formation of the FGLs can be divided into three stages: preparatory, formation, and pseudo steady-state. Yongshu Island (a reclaimed island) was used as a case study. The island’s preparatory phase lasted approximately 2.5 years, and will take 20 years to form a stable FGL (with a thickness of about 15 m). Recharge rates, and the nature of the contact between the Holocene and the underlying Pleistocene aquifers, determine the shape of the FGLs beneath the island. Abstraction during the formative period of the FGLs will increase the time required to reach a stable state. The results obtained enhance the understanding of the formation of FGLs, and can provide a reference for the management of freshwater resources on atoll islands.

In this paper we present a research of propagation characteristics of global Rossby wave and mesoscale eddies, and we preliminarily discussing the relationship between them from multiple datasets analysis. By filtering the MSLA-H data and by means of optimized SSH method we have extracted signals of the Rossby wave, and estimated the propagation speed (zonal phase speed) of the Rossby wave and eddies. Validation for the identification of the Rossby wave also has been completed with the Argo temperature and salinity data. The prime focus covers: propagation speed comparison between the Rossby wave and the eddies, propagation characteristics in different regions. Overlaying the signals of the Rossby wave with the signatures of the eddies indicates that the Rossby wave and the eddies propagates together (westward only) in the mid-latitude, but differences appear with increasing of latitude, especially in some areas affected by ocean current, for instance, the West Wind Drift(WWD) and the North Atlantic Drift(NAD). Actually we have found that the currents led the eddies, and the Rossby wave might play an accelerative or moderative role in the eddies propagation, as a result of the velocities of the eddies and the currents were matched well, but comparison between the Rossby wave and the eddies revealed disparity. The findings are useful for understanding the relationship between the Rossby wave and mesoscale eddies.

In this paper, polyaniline-coated silver phosphate has been successfully prepared via a facile chemisorption method in order to improve the stability of Ag3PO4 under light irradiation. The crystalline phase, band gap energy, and microstructure of the obtained PANI/Ag3PO4 composites were characterized by X-ray diffraction, UV–vis diffuse reflection spectroscopy, scanning electron microscopy, and transmission electron microscopy, respectively. The photocatalytic degradation of methlylene blue was performed to test the activities of PANI/Ag3PO4 composites with different coating amounts and the results indicate that the stabilities of PANI/Ag3PO4 composites were successfully enhanced. The correlation between photocatalytic performance and the properties of PANI/Ag3PO4 composites is discussed in detail.

Acoustic injection is one of the most dangerous ways of causing micro-electro&ndash, mechanical systems (MEMS) failures. In this paper, the failure mechanism of acoustic injection on the microprocessor unit 6050 (MPU6050) accelerometer is investigated by both experiment and simulation. A testing system was built to analyze the performance of the MPU6050 accelerometer under acoustic injection. A MEMS disassembly method was adopted and a MATLAB program was developed to establish the geometric model of MPU6050. Subsequently, a finite element model of MPU6050 was established. Then, the acoustic impacts on the sensor layer of MPU6050 were studied by acoustic&ndash, solid coupling simulations. The effects of sound frequencies, pressures and directions were analyzed. Simulation results are well agreed with the experiments which indicate that MPU6050 is most likely to fail under the sounds of 11,566 Hz. The failure mechanism of MPU6050 under acoustic injection is the relative shift of the capacitor flats caused by acoustic&ndash, solid resonance that make the sensor detect false signal and output error data. The stress is focused on the center linkage. MPU6050 can be reliable when the sound pressure is lower than 100 dB.

Selective laser melting (SLM) produces complex physical behaviors. After laser melting, the molten pool condenses with an uneven surface, which influences the next powder spreading process and affects the quality of the final product. This phenomenon is mainly caused by the Marangoni effect, which is generated by the surface tension of the liquid. This paper describes a method to control the surface deformation during the SLM of AlSi10Mg powder. It is assumed that there is a magnetic field (MF) added to the alloy powder generating a Lorentz force in the molten pool (MP). The Lorentz force can decrease the impact of the Marangoni effect and change the velocity field. Our work simulates the AlSi10Mg alloy melting process, and analyzes the physical parameters of the MP with or without an MF. It is found that increasing the MF within a certain range decreases the impact of the Marangoni effect, resulting in a smoother surface.

Intensity mapping is a promising technique for surveying the large scale structure of our Universe from $z=0$ to $z \sim 150$, using the brightness temperature field of spectral lines to directly observe previously unexplored portions of out cosmic timeline. Examples of targeted lines include the $21\,\textrm{cm}$ hyperfine transition of neutral hydrogen, rotational lines of carbon monoxide, and fine structure lines of singly ionized carbon. Recent efforts have focused on detections of the power spectrum of spatial fluctuations, but have been hindered by systematics such as foreground contamination. This has motivated the decomposition of data into Fourier modes perpendicular and parallel to the line-of-sight, which has been shown to be a particularly powerful way to diagnose systematics. However, such a method is well-defined only in the limit of a narrow-field, flat-sky approximation. This limits the sensitivity of intensity mapping experiments, as it means that wide surveys must be separately analyzed as a patchwork of smaller fields. In this paper, we develop a framework for analyzing intensity mapping data in a spherical Fourier-Bessel basis, which incorporates curved sky effects without difficulty. We use our framework to generalize a number of techniques in intensity mapping data analysis from the flat sky to the curved sky. These include visibility-based estimators for the power spectrum, treatments of interloper lines, and the "foreground wedge" signature of spectrally smooth foregrounds., 25 pages, 4 figures. Replaced to match accepted ApJ version; added table of variable names and minor pedagogical improvements in text (no changes to results)

A complex ternary BiPO/TiO/gCN heterostructure has been obtained from a simple impregnation method having good photoactivities for the degradation of phenol under solar-like irradiation. From the wide structural, surface and electronic characterization, we have stated that the formation of the ternary heterojunction notably affect photoactivity of pristine TiO. Thus, the best result for the binary system was obtained for 70wt% TiO-30wt% BiPO system. The incorporation of gCN leads to a further improvement on the photocatalytic activity when it is specifically done over TiO. By means of photoluminescence spectroscopy and reactive oxygen species formation test, we propose that the effective charge carrier separation is taking place through a cascade-driven electronic mechanism. Therefore, by choosing the adequate band-engineering tailoring an important improved photoactivity can be achieved., S. Obregón also thanks CSIC for the concession of a JAE-Pre grant. The financial support by projects P09-FQM-4570 and ENE2011-24412 is fully acknowledged.

We present a new method to fabricate nano-scale domain structures in bulk Mg-doped LiNbO3 crystals with the assistance of thermal fixing technique. Domain structures with hundred-nanometer width and millimeter length can be fabricated using this method. SEM image reveals a feature of smooth sidewall for the nano-scale domain structures.

We derive a suite of generalized Boltzmann equations, based on the density-matrix formalism, that incorporates the physics of neutrino oscillations for two- and three-flavor oscillations, matter refraction, and self-refraction. The resulting equations are straightforward extensions of the classical transport equations that nevertheless contain the full physics of quantum oscillation phenomena. In this way, our broadened formalism provides a bridge between the familiar neutrino transport algorithms employed by supernova modelers and the more quantum-heavy approaches frequently employed to illuminate the various neutrino oscillation effects. We also provide the corresponding angular-moment versions of this generalized equation set. Our goal is to make it easier for astrophysicists to address oscillation phenomena in a language with which they are familiar. The equations we derive are simple and practical, and are intended to facilitate progress concerning oscillation phenomena in the context of core-collapse supernova theory., Comment: 13 pages; Submitted to Physical Review D

The article, published in Online First on 21 May 2016, DOI 10.1007/s11001-016-9270-7, has been retracted at the request of the data supplier, China National Offshore Oil Corporation (CNOOC), because permission has not been granted for the use of data. CNOOC does not consent to releasing the data in the article. The authors have forgotten to ask for permission before submitting the paper to the journal and they apologize for the oversight.