Search

Er3+/Yb3+ co-doped SrGdAlO4 up-conversion phosphors with a tetragonal phase were synthesized using solid state reaction method. The dominant up-conversion luminescent mechanism was deduced through analyzing the power dependencies, energy diagrams and fluorescence lifetimes. It is interesting that the emitting color was almost unchanged when adjusting the dopant contents of Er3+ and Yb3+, excitation power and ambient temperature. The emission intensity and color purity of SrGdAlO4: Er3+, Yb3+ sample can be notably enhanced by introducing Bi3+ ions. X-ray diffraction and band gap analysis illustrated that Bi3+ ions can increase the asymmetric surrounding environment of the SrGdAlO4 host lattice. Simultaneously, the change of microstrain value showed that the host crystalline is affected by Bi3+ ions codoping. Optical temperature sensing performance based on the thermal coupled energy levels 2H11/2 and 4S3/2 of Er3+ ions was evaluated in the visible light region. The absolutely sensitivity of SrGdAlO4: Er3+, Yb3+ and SrGdAlO4: Er3+, Yb3+, Bi3+ are 3.8 × 10−3 K−1 and 6.1 × 10−3 K−1 respectively. The results indicated that codoping Bi3+ ions can improve the luminescent intensity of SrGdAlO4: Er3+, Yb3+, but also strengthen its temperature sensing characteristics.

The microwave humidity sounder (MWHS) onboard the Fengyun-3D satellite is providing the data for profiling atmospheric temperature and moisture and has become an important data source for improving the weather forecasts. In this article, three data sources are utilized for assessing the MWHS on-orbit performance, including Global Navigation Satellite System Occultation Sounder (GNOS), ECMWF (European Centre for Medium-Range Weather Forecasts) Re-Analysis (ERA)-Interim reanalysis, and Advanced Technology Microwave Sounder (ATMS) data. GNOS-retrieved atmospheric profiles and the reanalysis data are used as inputs to the community radiative transfer model (CRTM) for simulating the MWHS brightness temperatures at the top of the atmosphere in July 2018 for characterizing the instrument performance. Since ATMS is a well-calibrated microwave sounding instrument onboard both Suomi NPP and NOAA-20 satellites, its measurements are also collocated with MWHS data for a consensus analysis using the simultaneous nadir overpasses (SNOs) method. In comparing GNOS simulations, MWHS upper air temperature sounding channels (3–6) have relatively larger biases (less than 2.5 K) than the water vapor sounding channels. However, the standard deviation of the difference between observations and simulations (O-B) is larger for water vapor sounding channels. For ERA simulations, MWHS sounding channels exhibit negative biases similar to GNOS results but the standard deviation of O-B at the water vapor channels is much smaller. When compared with ATMS water vapor channels, MWHS biases are mostly negative and agree with those from ERA simulation. Thus, the large uncertainty in simulating MWHS water vapor sounding channels from GNOS could result from the poor input water vapor profiles and high water vapor variability in the lower troposphere.

In this paper, we introduce the mixed ring loading problem, where the ring contains undirected and bidirected links. When the ring consists of two nodes, we consider the online mixed ring loading problem under three different scenarios including splittable, integer splittable and unsplittable. When the demands are (integer) splittable, we present an (asymptotically) optimal online algorithm. When the demands are unsplittable, we present an online algorithm which generalizes the previous result.

A series of Sm3+ ions doped Sr3Al2O6 phosphors was successfully synthesized via hydrothermal method. The crystal structure, morphology and luminescent properties of samples were analyzed by X-ray diffraction, scanning electron microscopy and photoluminescence spectra. All the samples took on cubic structure with Pa-3 space group. The Sr3Al2O6:Sm3+ phosphors could be excited by 405 nm and emit orange-red light peaked at 565, 609 and 660 nm. The effect of hydrothermal reaction time on the morphology and luminescent properties of phosphor was investigated. The influence of molar fraction of Sm3+ ions on the emission intensity of samples was studied and it has been found that the optimal dosage is 0.01. The calculated results by the first principle indicated that the Sm3+ ions will easily occupy the symmetric center site (Sr1). The results indicated that the luminescent intensity of Sr3Al2O6:Sm3+ phosphors could be modulated by reaction conditions of hydrothermal method.

Electrostatic charging of hospital personnel and patients during various activities increases the risk of electrostatic discharge (ESD) malfunctions of medical devices and the likelihood of patients’ adverse events. Therefore, the test level for ESD immunity of medical devices, specified in the IEC 60601-1-2 standard needs to reflect the reasonably maximum electrostatic voltages during usage. This study investigated the effects of material combinations and relative humidity on the body voltage while performing two routine clinical activities of lying down on a hospital bed and transferring to a bed using a sliding board. The peak body voltages in nearly 50% of the lying down experiments and 40% of sliding tests exceeded the test voltage level in the IEC 60601-1-2 standard (i.e., 15 kV). Using cotton blankets in lying down experiments and nylon sheets during sliding experiments resulted in 50% and 40% larger median than the median including all combinations, respectively. Sliding boards with antistatic coating reduced the peak body voltage by 24% on average, however, 33% of the tests still exceeded 15 kV. Based on the findings, recommendations are provided for healthcare facilities and medical device manufacturers to mitigate the risks of ESD malfunctions.

Cubic phase Ca9-xAl6O18:xEu3+ red phosphors have been successfully fabricated using the hydrothermal assisted solid state method. The atomic site occupation of the matrix, morphology, luminescent properties, quenching mechanisms, and thermal stabilities are investigated. The possible sites of Eu3+ in a matrix crystal lattice are investigated via formation energy using first principle calculations. Under 395 nm excitation, Ca9-xAl6O18:xEu3+ shows a red emission at 618 and orange emission at 594 nm and the optimal Eu3+ ion concentration is x = 0.06. The effect of the reaction solution composition on the morphology and emission spectra are investigated using SEM and photoluminescence (PL) spectrum measurements. The results reflect that the samples have different morphologies in different reaction solutions. Additionally, the PL intensities of Ca8.94Al6O18:0.06Eu3+ decreased to 80.6% as the temperature increased from room temperature to 150 °C. Ca9Al6O18:Eu3+ phosphors may potentially be used for white LEDs.

In order to find low-toxic light-absorbing materials for perovskite solar cells, the electronic structures and optical absorption spectra of doped perovskites CsPb₁–ₓMₓI₂Br (M = Ge, Sn, Sr, and Cu) have been investigated with the first-principles method. Ge- and Sn-doped perovskites display monotonously decreased band gaps with increasing x, opposite to Sr- and Cu-doped ones. Different from group IV Ge and Sn elements, Sr and Cu dopants show distinct electronic characteristics, that is, weak interaction with halogens because of the d orbitals splitting in octahedral complexes and unique density of states and band-decomposed charge densities. Meanwhile, Ge, Sn, and Cu dopants prefer substituting Pb sites in the CsI-terminated surfaces based on thermodynamic consideration, and the dopants accumulating on surfaces will deteriorate the optical absorption of perovskites based on the comparison of the absorption spectra of various doped structures. Therefore, this study provides a theoretical insight into the declined absorption spectra with the increasing concentration of dopants in experimental observations.

Ti3C2Tx MXenes and their composites play a vital role in the research on microwave absorbing materials. Herein, the different interlamellar spaces of Ti3C2Tx MXene materials were prepared by an etching process. The dependence of the microwave absorbing properties of the Ti3C2Tx MXene nanosheets on different interlamellar spaces was studied. The complex permittivity, dielectric loss, impedance matching characteristic and the minimum reflection loss (RL) value with the variation in interlamellar space were systematically investigated. Results showed that 40% ratio paraffin-bonded composites (S3) have a strong electromagnetic wave absorption performance and large effective absorbing bandwidth. The maximum RL reaches −36.3 dB at 4.67 GHz with the thickness of 4.5 mm, ascribed to its a high dielectric loss and good impedance matching characteristics. The RL value of Ti3C2Tx MXenes is strongly dependent on the inter-lamellar space. The enhanced microwave absorption originates from the unique 2-D structure, good impedance matching characteristics, and enhanced space-charge polarization effects. This work provides a new avenue for exploring high-performance microwave absorbers based on MXene materials.

Obtaining an ideal ferroelectric photovoltaic (FE-PV) material with a narrow bandgap and a large ferroelectric polarization value can enable us to achieve great practical FE-PV performance. By the introduction of sulfur into the tetragonal BiCoO3 perovskite with a C-type antiferromagnetic ordering, it is found that the bandgap of BiCoO2S decreases significantly (about 1.2 eV) while maintaining a large polarization value (about 1.86 C m−2) that is similar to the value of 1.793 C m−2 of BiCoO3. Most noteworthy is that the optical absorption of BiCoO2S is remarkably higher than those of BiCoO3 and other FE-PV materials. The decrease of the BiCoO2S bandgap originates from the movement of Co 3d states to a low-energy position due to the reduction of the Co ionicity when the less electronegative sulfur is introduced into BiCoO3 to substitute oxygen. The narrow bandgap and the high optical absorption of the BiCoO2S films grown on different substrates are favorable for FE-PV applications. In addition, the bandgap of BiCoO2S can be modulated by the doping amount of sulfur, which can help us fabricate multilayer FE-PV devices based on different bandgaps from different layers.

A series of Ca15(PO4)2(SiO4)6:xCe3+,yTb3+ phosphors have been prepared by a high-temperature solid-state reaction. Under the excitation of near-UV with 371 nm wavelength, Ca15(PO4)2(SiO4)6:xCe3+ phosphors exhibit strong blue emission with a broad peak at 432 nm. Based on the photoluminescence of Ca15(PO4)2(SiO4)6:xCe3+ phosphors, the coordination environment around Ce3+ ions and the concentration quenching mechanism are inferred. With the doping of Tb3+ ions into Ca15(PO4)2(SiO4)6:1.33%Ce3+, the luminescence color from blue to cyan can be well tuned. By measuring the luminescence intensity and lifetime of the as-prepared phosphors, it can be judged that there exists an energy transfer from Ce3+ to Tb3+. To achieve white light, the optimal Ca15(PO4)2(SiO4)6:1.33%Ce3+, 9%Tb3+ phosphors are mixed with commercial SrAlSiN3:Eu2+ powders and finally warm white light emission could be obtained. The results show that Ca15(PO4)2(SiO4)6:xCe3+,yTb3+ phosphors have potential applications in warm white light-emitting diodes.

Qihui Chu,1,* Weiwei Mu,1,* Chuanjin Lan,2 Yang Liu,1 Tong Gao,1 Li Guan,1 Yuxiao Fang,1 Zipeng Zhang,1 Yingchao Liu,2 Yongjun Liu,1 Na Zhang1 1Department of Pharmaceutics, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, 250012, People’s Republic of China; 2Department of Neurosurgery, Shandong Provincial Hospital Affiliated with Shandong First Medical University, Jinan, 250021, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yongjun Liu; Na Zhang Email liuyongjun@sdu.edu.cn; zhangnancy9@sdu.edu.cnPurpose: Specific targeting receptors for efficiently capturing and applicable nanodevice for separating and instant observing of circulating tumour cells (CTC) are critical for early diagnosis of cancer. However, the existing CTC detection system based on epithelial cell adhesion molecule (EpCAM) was seriously limited by low expression and poor specificity of targeting receptors, and not instant observation in clinical application.Methods: Herein, an alternative glypican-3 (GPC3)-based immunomagnetic fluorescent system (C6/MMSN-GPC3) for high-specific isolation and instant observation of CTC from hepatocellular carcinoma (HCC) patients’ peripheral blood was developed. The high-specific HCC targeting receptor, GPC3,was employed for improving the sensitivity and accuracy in CTC detection. GPC3 monoclonal antibody (mAb) was linked to immunomagnetic mesoporous silica for specific targeting capture and separate CTC, and fluorescent molecule coumarin-6 (C6) was loaded for instant detection of CTC.Results: The cell recovery (%) of C6/MMSN-GPC3 increased in 106 HL-60 cells (from 49.7% to 83.0%) and in whole blood (from 42% to 80.3%) compared with MACS® Beads. In clinical samples, the C6/MMSN-GPC3 could capture more CTC in the 13 cases of HCC patients and the capture efficiency was improved by 83.3%– 350%. Meanwhile, the capture process of C6/MMSN-GPC3 was harmless, facilitating for the subsequent culture. Significantly, the C6/MMSN-GPC3 achieved the high-specific isolation and instant observation of CTC from HCC patients’ blood samples, and successfully separated CTC from one patient with early stage of HCC (Stage I) and one post-surgery patient, further indicating the potential ability of C6/MMSN-GPC3 for HCC early diagnosis and prognosis evaluation.Conclusion: Our study provides a feasible glypican-3 (GPC3)-based immunomagnetic fluorescent system (C6/MMSN-GPC3) for high-specific isolation and instant observation of HCC CTC.Keywords: immunomagnetic fluorescent system, circulating tumour cells, hepatocellular carcinoma, glypican-3, early diagnosis

In this paper, we firstly introduce the definition of the fuzzy metric of sets, and discuss the properties of fuzzy metric induced by the Hausdorff metric. Then we prove the limit theorems for set-valued random variables in fuzzy metric space, the convergence is about fuzzy metric induced by the Hausdorff metric. The work is an extension from the classical results for set-valued random variables to fuzzy metric space.

The electroactive β-phase in Poly (vinylidene fluoride, PVDF) is the most desirable conformation due to its highest pyro- and piezoelectric properties, which make it feasible to be used as flexible sensors, wearable electronics, and energy harvesters etc. In this study, we successfully developed a method to obtain high-content β-phase PVDF films and nanofiber meshes by mechanical stretching and electric spinning. The phase transition process and pyro- and piezoelectric effects of stretched films and nanofiber meshes were characterized by monitoring the polarized light microscopy (PLM) images, outputting currents and open-circuit voltages respectively, which were proved to be closely related to stretching ratio (λ) and concentrations. This study could expand a new route for the easy fabrication and wide application of PVDF films or fibers in wearable electronics, sensors, and energy harvesting devices. Supplementary Information The online version contains supplementary material available at 10.1186/s11671-021-03536-9.

Herein, we reported Er3+/Yb3+ co-doped CaLaAl3O7 up-conversion phosphors synthesized via solid state reaction, which was further explored as a new optical thermometry. The luminescent properties of Er3+ or Er3+/Yb3+ doped CaLaAl3O7 phosphor was studied in detail. The two-photon process for the green emissions of Er3+ were confirmed by the power-dependent luminescence. The up-conversion optical temperature sensing performances of the Er3+/Yb3+-codoped CaLaAl3O7 phosphor were investigated based on the FIR technique. The maximum sensitivity of this phosphor can reach about 0.00345 K−1 at 453 K, which reveals this phosphor can be a promising candidate for optical thermometry devices.

In water quality detection by ultraviolet-visible (UV–vis) spectroscopy, the detection equipment faces diverse water bodies. It is easy to be interfered by turbidity caused by suspended solid particles (SSP), resulting in a nonlinear rise of the whole spectrum and a significant decrease in measurement accuracy of chemical oxygen demand (COD). A turbidity compensation algorithm for UV–vis spectroscopy based on Lambert-Beer’s law for fitting the absorbance caused by turbidity in the whole spectrum region is studied. According to the additivity of absorbance, a few absorbance spectra of turbidity were obtained by filtering and difference method. They are then used as base spectra to linearly fit the absorbance spectrum of any turbidity value water. Finally, turbidity compensation of all samples in the whole region is realized by the subtraction method. Compared with 350 nm proportional compensation (350 nm PC) and multiplicative scatter correction (MSC), the compensated spectra of the method proposed in this paper are in the best coincidence with the filtered spectra by a 0.45 um filter membrane. Partial least squares (PLS) method is used to establish the COD prediction model of the raw spectra and compensated spectra of the three methods. The results show that the Rpred of the proposed method is the biggest and the RMSEP is the smallest. The experimental results show that the proposed turbidity compensation method can effectively correct the absorption spectrum without affecting the absorption characteristics of water samples. Furthermore, improving the accuracy of COD measurement by UV–vis spectroscopy.

α-SiC particles were used as heating seeds to prepare SiC from coal minerals with microwave heating method. Coating technique was carried out to prepare composite raw powders in three different methods. Heating temperatures were at 1000 °C, 1050 °C, 1100 °C, 1150 °C, 1200 °C for 10min, respectively. XRD, SEM techniques were carried out to characterize samples. It was found that different distribution between C and α-SiC particles from different mixing method leads to different microwave heating behavior and growth mechanisms. V-V reaction leads to in situ nucleation and grain growth on the surface of α-SiC seeds which contact with C particles. Well-grown β-SiC particulates appear. Hybrid V-V reaction V-L reaction lead to local microwave plasma and diffusion-precipitation with a very thin layer of SiO2 between raw C particles and α-SiC seeds. Local fine β-SiC whiskers and particulates on the surface of α-SiC seeds co-exist. Primary V-V reaction leads to nucleation and grain growth along reacted C-SiO2 interface with very thick layer of SiO2 between raw C and α-SiC seeds. Substantial β-SiC whiskers appear. Transformation from β-SiC to α-SiC on the surface of as-formed whiskers will be enhanced by microwave plasma at high temperature.

The interfacial effect on the dynamical properties of spin-dependent polarons in an organic magnetic/nonmagnetic co-oligomer is investigated by using a tight-binding model coupled with a nonadiabatic dynamic method. It is found that the dynamical behaviors of spin-up and spin-down polarons are quite different at the interface. In the presence of an external electric field, polarons with a specific spin (up or down) can get trapped near the magnetic/nonmagnetic interface while the motion of polarons with an opposite spin is not affected, which leads to the phenomenon of polaron spin-filtering. Interestingly, when the electric field is reversely applied, only polarons with opposite spin can pass through the co-oligomer and spin rectification can be observed. The spin-filtering and rectification can be improved by increasing the strength of the spin correlation in the magnetic part of the co-oligomer and they can also be affected by the strength of the interfacial electron–lattice coupling and the electronic...

Based on the first-principles calculations, the influence of different geometry models on the theoretical results about the electronic properties of LaAlO3/SrTiO3 perovskite heterostructures has been studied. The results show that the superlattice model can indicate n-type conductivity of interfaces, but it is limited to describe the insulator-metal transition of heterostructures. The sandwich and thin film models with the vacuum layer can take into account the surface termination effect on the electronic properties of the interface. The AlO2 or LaO atomic layer as the outmost surface termination is selected during constructing the model, leading to the distinct electronic properties of the heterostructures. The build-in electric filed appears in the AlO2-terminated structure, whereas it does not exist in LaO-terminated structure. Therefore, the AlO2-terminated structure can give a clear description about the insulator-metal transition of heterostructure and the charge transfer mechanism. The build-in electric filed, the atomic rumpling and surface termination effect of perovskite materials codetermine the conductivity of interfaces. The results would be helpful to construct theoretical model and understand the novel electronic properties during investigating other perovskite heterostructures.

A novel Eu3+ ion-doped yttrium silicomolybdic (Y2MoSiO8) phosphor was prepared by traditional high-temperature solid-state reaction at 1200 °C. XRD analysis verified the phosphor had a pure tetragonal structure. The morphology, photo-luminescent (PL), lifetime, color rendering, and stability properties of the phosphor were investigated. When excited under 395 nm, Y2MoSiO8:Eu3+ phosphor can emit red light that peaks at 618 nm and 595 nm. The concentration of Eu3+ ions has an important effect on the emission intensity of phosphor, and the optimal molar fraction of Eu3+ ions is 0.12. The phosphors also exhibit high thermal stability with an activity energy ΔE value of 0.29 eV. The results indicate that Y2MoSiO8:Eu3+ phosphor is a potential candidate for white LEDs.

A series of CdSe QDs are synthesized using four kinds of ligands including dodecylamine, tetradecylamine, 1-hexadecanamine and octadecylamine by organic metal preparation method. The XRD patterns revealed that all the CdSe QDs with different amine ligands belong to cubic phase. The monodisperse CdSe QDs are obtained and their average size increases with the Carbon chain length of amine ligands. The absorption peaks of CdSe QDs capping with different amines shift from 526 to 557 nm. The results indicated that the luminescent properties and size of CdSe QDs can be modulated by amine ligand in the process of synthesis.

In this work, we report the preparation and the enhanced electrochemical performance of P2-type Na0.67Lix(Mn0.5Fe0.25Co0.25)1−xO2 layered cathode materials with different Li substitutions via a nanomilling-assisted solid-state method. The experimental results show that the introduced lithium ions can greatly improve the performance of the material after entering the transition metal layer. Among these synthesized samples, the Na0.67Li0.03(Mn0.5Fe0.25Co0.25)0.97O2 electrode exhibits an exceptionally high specific capacity of 190.6 mAh g−1 at 0.1 C rate and a capacity retention of 89.5% after 30 cycles. Obviously, the specific capacity retention is improved by 15.3% compared with the pristine Na0.67(Mn0.5Fe0.25Co0.25)O2 without Li incorporation (the specific capacity retention is only 74.2% after 30 cycles). Simultaneously, the sample also shows a large increase in rate performance compared to the pristine material. All of the enhancement can be explained by the fact that the introduced Li ions suppress the phase transition during the charge–discharge process and avoid the volume expansion of the electrode, which significantly reduce the occurrence of micro-cracks within the electrode. The reduced polarization, the decreased internal resistance of the prepared electrodes and the increased sodium ion diffusion coefficient, as confirmed from the CV and EIS measurements, can be regarded as the three major reasons for the enhanced electrochemical performance of the Li ion-substituted materials.

According to gaining importance of power electronics systems in the society, reliability issues of power semiconductor devices are the constrains on availability of the system operations. Regular interval based maintenance for higher availability, on the other hand, increases operation cost since the lifetime of power devices have a large deviation with production lots or conditions which they are used. Condition based maintenance (CBM) of power semiconductor devices will be a promising solution for both the availability and cost of power electronics system maintenance. In this study, a high signal resolution condition monitoring system board has been demonstrated. The system monitors real time V-I curve for both switching device and diode with case temperature and the data is stored on board memory and can be monitored on-line. The board was mounted on the gate driver board being supplied power from the gate driver board and demonstrated on a commercial 60kVA inverter., 32nd International Symposium on Power Semiconductor Devices and ICs (ISPSD 2020), 13-18 September, 2020, Vienna, Austria （新型コロナ感染拡大に伴い、現地開催中止）

Recently, new cationic antibacterial peptide OM19R has been designed with low minimum inhibitory concentration (MIC) values against some gram-negative bacteria, such as Escherichia coli, Salmonella, and Shigella. However, this hybrid peptide, like most antibacterial peptides, has low enzyme stability and short half-life, which, in turn, increases the drug's cost. In this study, an antibacterial peptide (OM19r-8) was obtained containing some D-Arg amino acids. The new preparations were carried out through the replacement of l -Arginine by d -Arginine and the addition of PEG chains. Firstly, eight OM19r series of antibacterial peptides were obtained by designing D-Arg. Then, a polyethylene glycol-modified product mPEG5-butyrALD-OM19r-8 (mPEG5-OM19r-8) was isolated and purified by reverse-phase high-performance liquid chromatography (RT-HPLC). The enzyme stability test showed that the resistance of antibacterial peptide OM19r-8 to protease degradation increased by 4-32-fold. Moreover, the Time-kill studies showed that the germicidal kinetics curves of mPEG5-OM19r-8 and OM19r-8 to Escherichia coli had a similar trend, thus suggesting that PEG modification has an acceptable effect on the activity of the original peptide. Furthermore, the elimination of half-life (28.09 ± 2.81min) of mPEG5-OM19r-8, and the area under the drug concentration-time curve (2686.48 ± 651.36min∗ug/ml) was significantly prolonged. The current study demonstrates an example that optimizes the AMP by utilizing L-to-D amino acid replacement and including PEG chains. These results provide useful data for the clinical application of the mPEG5-OM19r-8.

Reliable and efficient risk assessments are essential to deal effectively with potential risks in international construction projects. However, most conventional risk modeling methods are based on the hypothesis that risk factors are independent, which does not account adequately for the causal relationships among risk factors. In this study, a risk assessment model for international construction projects was developed to improve the efficacy of risk management by integrating fault tree analysis and fuzzy set theory with a Bayesian belief network. The risk rating of each risk factor, expressed as the product of risk occurrence probability and impact, was incorporated into the risk assessment model to evaluate degrees of risk. Therefore, risk factors were categorized into different risk levels taking into account their inherent causal relationships, which allowed the identification of critical risk factors. The applicability of the fuzzy Bayesian belief network-based risk assessment model was verified using a case study through a comparative analysis with the results from a fuzzy synthetic evaluation method. The comparison shows that the proposed risk assessment model is able to provide guidelines for an effective risk management process and ultimately to increase project performance in a complex environment such as international construction projects.

Antibiotic resistance has become a global public health concern, rendering common infections untreatable. Given the widespread occurrence, increasing attention is being turned toward environmental pathways that potentially contribute to antibiotic resistance gene (ARG) dissemination outside the clinical realm. Studies during the past decade have clearly proved the increased ARG pollution trend along with gradient of anthropogenic interference, mainly through marker-ARG detection by PCR-based approaches. However, accurate source-tracking has been always confounded by various factors in previous studies, such as autochthonous ARG level, spatiotemporal variability and environmental resistome complexity, as well as inherent method limitation. The rapidly developed metagenomics profiles ARG occurrence within the sample-wide genomic context, opening a new avenue for source tracking of environmental ARG pollution. Coupling with machine-learning classification, it has been demonstrated the potential of metagenomic ARG profiles in unambiguously assigning source contribution. Through identifying indicator ARG and recovering ARG-host genomes, metagenomics-based analysis will further increase the resolution and accuracy of source tracking. In this review, challenges and progresses in source-tracking studies on environmental ARG pollution will be discussed, with specific focus on recent metagenomics-guide approaches. We propose an integrative metagenomics-based framework, in which coordinated efforts on experimental design and metagenomic analysis will assist in realizing the ultimate goal of robust source-tracking in environmental ARG pollution.

L-Methionine (L-Met) is one of the essential amino acids in human health, efficiently detect L-Met is a significant issue. Herein, a concept “dual-site collaborative recognition” had been successfully introduced into the design and achieved high selective and sensitive recognition of L-Met. In order to realize the “dual-site collaborative recognition”, we rationally designed and synthesized an ester functionalized pillar[5]arene-based fluorescent sensor (SP5). And it shows blue Aggregation-induced emission (AIE) fluorescence. In the SP5, the pillar[5]arene group act as C-H···π interactions site, and ester group serve as multi hydrogen bonding acceptor. Interestingly, the SP5 exhibited high selectivity and sensitivity (2.84 × 10−8 M) towards L-Met based on the collaboration of electron-rich cavernous pillar[5]arene group and ester group through C-H···π and H-bond interactions, respectively. This “dual-site collaborative recognition” mechanism has been investigated by 1H NMR, ESI-MS and theoretical calculation including frontier orbital (HOMO and LUMO), electrostatic potential (ESP) and the noncovalent interaction (NCI). These theoretical calculations not only support the proposed host-guest recognition mechanism, but also provided visualized information on the “dual-site collaborative recognition” mode. Furthermore, the concept “dual-site collaborative recognition” is an effective strategy for easily detecting biological molecules.

Black phosphorus quantum dots for efficient photovoltaic application., Black phosphorus quantum dots (BPQDs) are proposed as effective seed-like sites to modulate the nucleation and growth of CsPbI2Br perovskite crystalline thin layers, allowing an enhanced crystallization and remarkable morphological improvement. We reveal that the lone-pair electrons of BPQDs can induce strong binding between molecules of the CsPbI2Br precursor solution and phosphorus atoms stemming from the concomitant reduction in coulombic repulsion. The four-phase transition during the annealing process yields an α-phase CsPbI2Br stabilized by BPQDs. The BPQDS/CsPbI2Br core-shell structure concomitantly reinforces a stable CsPbI2Br crystallite and suppresses the oxidation of BPQDs. Consequently, a power conversion efficiency of 15.47% can be achieved for 0.7 wt % BPQDs embedded in CsPbI2Br film-based devices, with an enhanced cell stability, under ambient conditions. Our finding is a decisive step in the exploration of crystallization and phase stability that can lead to the realization of efficient and stable inorganic perovskite solar cells.

LiNbO3 (LN) crystal has been widely used as a pyroelectric material due to its spontaneous electric polarization, which could be recharged easily and can directly convert heat energy into electricity. LN crystal’s heat-resistant, low-cost, and low dielectric loss properties make it possible for its applications in room-temperature pyroelectric devices and thermal sensors. However, LN crystal suffers from fragility, inflexibility, and other mechanical properties, which limit its suitability for many applications in various fields. In this study, the LN modified flexible pyroelectric films, composed of LN micro-particles, polypropylene (PP) matrix, and multiwalled carbon nanotubes (MWCNTs), are successfully fabricated. The pyroelectric effects of LN crystal and LN/PP/MWCNT composite films are characterized by monitoring the patterned self-assembly of nanoparticles and the output pyroelectric currents. The excellent pyroelectric properties of the composites have potential applications in energy harvesters or sensors.

A green and economical microwave–hydrothermal method is employed to prepare carbon dots (CDs) that low-cost dl-malic acid serves as the carbon source and the formamide serves simultaneously as the pyrolysis solvent and carbon source. In the reaction process, neither assistant catalytic treatment nor further surface modification is necessary. We obtain better disperse CDs powders whose quantum yield reaches 25% as well as explain the dehydration condensation reaction mechanism based on the analysis by XPS and FTIR data. The luminescent properties are investigated in detail, and the results reveal that the excitation-dependent feature of as-prepared CDs has the potential for anti-counterfeiting mark and luminescence picture field.

In a near-field scanning system, each element of the measurement chain contributes to the thermal noise power density: probe, cables, amplifiers, and the measuring instrument. The signal-to-noise ratio (SNR) is strongly affected by the source output impedance, source temperature, the lossy transmission lines between probe and amplifiers, amplifier noise, amplifier temperature, and amplifier gain. By minimizing the loss between the probe and by using ultralow-noise amplifiers (noise figure (NF) 10 dB, compared to a setup using a 1-m cable and a 3-dB NF amplifier. A resonant probe that is cooled with liquid nitrogen improves measurement SNR by an additional 10–12 dB, as compared to a broadband probe of similar loop size. To combine the advantages of a resonant probe, without sacrificing the ability to measure broadband, a proof of concept is demonstrated that uses a tunable resonant probe which is synchronized to the frequency sweep of the spectrum analyzer.

Photogenerated charge separation and redox reactions on photoexcited semiconductors are of great significance in many photon excited systems, such as photocatalytic water splitting systems, photocatalytic pollutant removal systems, photovoltaic devices, etc. It is highly desirable if we know the charge separation directions inside the semiconductor crystals, the preferred crystal facets the charge accumulate after separation, and the preferred facets where redox reactions occur, so we can grow the semiconductor crystals accordingly with the desired facets exposed on the surface to have large numbers of the photoaccumulated electrons and holes on the facets in order to realize a high photocatalytic efficiency for both oxidation and reduction on the surface or to achieve a large photovoltaic efficiency. Here, we attempt to convert the information from the electronic band structure calculations in the k space into the real space in bulk crystals and combine the surface electronic band structures of various f...

The contaminant detection in water is important to secure public health against potentially harmful substances. As a noninvasive detection technique, ultraviolet-visible (UV-Vis) spectroscopy is studied and widely applied in detecting water contamination. However, current methods for contamination detection reveal the defects of noise sensitivity and data redundancy. In this study, de-noising and dimensionality reduction of UV-Vis absorption spectrum are focused on. With regards to de-noising, the influence of various discrete wavelet transforms families, decomposition levels and threshold methods on UV-Vis absorption spectrum de-noising are analyzed and discussed in detail. Concerning dimensionality reduction, the principal component analysis (PCA) is utilized. The performance of de-noising and dimensionality reduction is assessed by signal-to-noise ratio (SNR) and normalized reconstruction error ( e n o r m ), respectively. Results from experiments and analysis reveal the decomposition level and wavelet transforms families are the most significant parameters influencing the de-noising algorithm efficiency. Moreover, using sym5 at five level decomposition with hard threshold method had the best effect for UV-Vis absorption spectrum de-noising. Besides, PCA can project UV-Vis absorption spectrum to a much lower dimension but representative data space.

Red or near-infrared phosphors, which have a lower absorption in biological tissue, show excellent promise in the field of bioimaging. Here, we design the red phosphor with a broad emission band and realize tunable luminescence of Cr3+ by two methods, i.e., adjusting the Cr3+-doping concentration in Zn3(AlGa)2Ge2O10 solid solution and doping In3+ ions in Zn3Al2Ge2O10 due to a size mismatch. The solid solution is illustrated by density functional theory calculation, X-ray powder diffraction, and high resolution transmission electron microscopy. The Cr3+-doped phosphor shows a red emission band centered at 705 nm, which is ascribed to the 2E → 4A2 and 4T2(4F) → 4A2 transitions. When Cr3+ ions or In3+ ions are introduced, the full width at half-maximum (fwhm) increased due to the combination of crystal field splitting, nephelauxetic effect, and reabsorption.

The D-π-A methine chain electrophilic substitution reactions for directly introducing some functional groups to the dipole conjugate chain, with mild conditions and good yields, are disclosed. This method is shown to efficiently replace the hydrogen on the D-π-A methine chain with an electrophile to synthesize methine-substituted Cy3.5 in one step.

The underlying cause of most electrostatic discharge is tribocharging. Thus, understanding tribocharging is essential to assess the likelihood of damages as they might occur in the production of liquid crystal display (LCD) screens. In this paper, a study of triboelectric charge build-up between the glass and rollers during the glass transfer process in display panel manufacturing is presented. A roller conveyor system was fabricated and two types of rollers materials, insulative and dissipative, with radii of 30 and 90 mm, were considered. To measure the triboelectric charge of the glass, a Faraday cup with an elevator system was mounted on the apparatus. Various parameters including transfer velocity, acceleration/deceleration, and relative humidity were investigated. For instance, it is observed that the average saturated charge density on the glass is 0.324 nC/cm2 after 320-m displacements if it transfers by small dissipative rollers with condition of 200 mm/s and 200 mm/s 2. In addition, a comprehensive study of the surface potential distribution on the glass and rollers by utilizing a two-dimensional automated scanner is presented. The experiments pointed out that the amount of charge accumulated on the glass for the dissipative rollers saturated faster with a smaller value than the insulative rollers.

Project risks are mostly considered to be independent in risk management, ignoring interdependencies among them, which can lead to inappropriate risk assessment and reduced efficacy in risk treatment. This study introduces a new Monte Carlo simulation-based risk interdependency network model to support decision makers in assessing project risks and planning risk treatment actions more effectively. The Interpretive Structural Modeling method is integrated into this model to develop a hierarchical project risk interdependency network based on identified risks and their cause-effect relationships. The Monte Carlo method is used to model the stochastic behavior of risk occurrence and to generate numerous possible risk scenarios through simulation. To evaluate single risks and overall project risk level while considering risk interdependencies, five major risk indicators are therefore proposed, namely simulated occurrence probability of a risk, simulated local and global influence of a risk, as well as total risk loss and total risk propagation loss of a project. An additional sensitivity analysis is also included to examine the effects of input uncertainties of this model on risk assessment results. Moreover, two case studies are provided to demonstrate the application and effectiveness of the proposed model. The findings accentuate the significance of considering risk interdependencies in project risk assessment and validate the model's robustness and feasibility in risk management of projects with complex interrelated risks.

Wearable pressure sensors have attracted increasing attention for biomechanical monitoring due to their portability and flexibility. Although great advances have been made, there are no facile methods to produce sensors with good performance. Here, we present a simple method for manufacturing flexible and self-powered piezoelectric sensors based on LiNbO3 (LN) particles. The LN particles are dispersed in polypropylene (PP) doped with multiwalled carbon nanotubes (MWCNTs) by hot pressing (200 °C) to form a flexible LN/MWCNT/PP piezoelectric composite film (PCF) sensor. This cost-effective sensor has high sensitivity (8 Pa), fast response time (ca. 40 ms), and long-term stability (>3000 cycles). Measurements of pressure changes from peripheral arteries demonstrate the applicability of the LN/MWCNT/PP PCF sensor to biomechanical monitoring as well as its potential for biomechanics-related clinical diagnosis and forecasting.

Sr4-xSi3O8Cl4:xEu3+ (SSOC:Eu3+) phosphors were successfully synthesized by hydrothermal method. The crystallization of this phosphor was analyzed by means of X-ray diffraction patterns. The size and morphology were recorded using SEM patterns of samples. And the PLE and PL spectra were characterized by a PL spectrophotometer. Excited by 394 nm UV light, the intense red emission is recognized in SSOC:Eu3+ phosphor and the main emission peak located at 620 nm. The influences of Eu3+ concentration, pH value of reaction solution, and charge compensator on PL spectra of SSOC:Eu3+ phosphors were investigated. The results revealed that this red phosphor had potential applications for white LEDs.

Glass substrates for displays are insulating materials capable of generating and maintaining high levels of triboelectric charges posing a risk of electrostatic discharge (ESD) damage to electronic display components. In this work, an apparatus for triboelectric charging characterization of display glass during the roller transfer process was designed and fabricated. In order to establish the reliability of the characterization, the triboelectric charge and the electrostatic potential distribution measurement system was automated. The preconditioning process of the glass and the rollers was also addressed. In order to analyze the measurements' results, a multiphysics model that considered both electrical and mechanical properties was proposed. The test parameters that were expected to affect the triboelectric charging characteristics are defined and discussed, as well as some of the characterization results such as the effects of acceleration/deceleration and maximum velocity, relative humidity and moisture on the glass and the rollers, and the conductivity of the rollers. The peak-to-peak deviation of the de-embedded triboelectric charges, due to a steady-state velocity period with different combinations of acceleration/deceleration and maximum velocities, was 14.2%. The triboelectric charges increased as the relative humidity increased from 30% to 50% with the same temperature. They also increased when the insulating rollers were replaced with dissipative rollers.

In this work, the near-nozzle spray characteristics of soybean biodiesel, di-n-butyl ether (DBE)/biodiesel blends and 0# diesel were investigated by using a high pressure common-rail injection system and the effect of experiment conditions and fuel physical properties on the near-nozzle spray structures were explored. Microscopic spray images at the near-nozzle field were captured by the high-resolution microscopy. The micro spray cone angle and micro projected spray area were obtained from the processed spray images for quantitative analysis. The results show that the initial spray of diesel is easier to breakup into ligaments and droplets because of smaller surface tension and viscosity compared to that of biodiesel under atmospheric condition. The spray with more ligaments was easily restrained by the ambient gas and promoted to evolve along the radial direction, leading to a wider micro spray cone angle of diesel. The breakup of liquid jet also tends to increase the micro projected spray area of diesel. When 30% of DBE was added into biodiesel, both the micro spray cone angle and projected spray area were increased due to the decreased surface tension and viscosity of the blended fuel. The initial spray images reveal that the high injection pressure favors the spray primary breakup while the high ambient pressure results in worse spray primary breakup. The quantitative analysis shows that the injection pressure has little influence on the micro spray cone angle but results in the increase in micro projected spray area, while both parameters increase significantly under high ambient pressures.

Direct assimilation of cloud-affected microwave brightness temperatures from AMSU-A into the GSI three-dimensional variational (3D-Var) assimilation system is preliminarily studied in this paper. A combination of cloud microphysics parameters retrieved by the 1D-Var algorithm (including vertical profiles of cloud liquid water content, ice water content, and rain water content) and atmospheric state parameters from objective analysis fields of an NWP model are used as background fields. Three cloud microphysics parameters (cloud liquid water content, ice water content, and rain water content) are applied to the control variable. Typhoon Halong (2014) is selected as an example. The results show that direct assimilation of cloud-affected AMSU-A observations can effectively adjust the structure of large-scale temperature, humidity and wind analysis fields due to the assimilation of more AMSU-A observations in typhoon cloudy areas, especially typhoon spiral cloud belts. These adjustments, with temperatures increasing and humidities decreasing in the movement direction of the typhoon, bring the forecasted typhoon moving direction closer to its real path. The assimilation of cloud-affected satellite microwave brightness temperatures can provide better analysis fields that are more similar to the actual situation. Furthermore, typhoon prediction accuracy is improved using these assimilation analysis fields as the initial forecast fields in NWP models.

We discuss two different integration methods for radar-based quantitative precipitation estimation (QPE): the echo intensity integral and the rain intensity integral. Theoretical analyses and simulations were used to test differences between these two methods. Cumulative rainfall calculated by the echo intensity integral is usually greater than that from rain intensity integral. The difference of calculated precipitation using these two methods is generally smaller for stable precipitation systems and larger for unstable precipitation systems. If the echo intensity signal is sinusoidal, the discrepancy between the two methods is most significant. For stratiform and convective precipitation, the normalized error ranges from −0.138 to −0.15 and from −0.11 to −0.122, respectively. If the echo intensity signal is linear, the normalized error ranges from 0 to −0.13 and from 0 to −0.11, respectively. If the echo intensity signal is exponential, the normalized error ranges from 0 to −0.35 and from 0 to −0.30, respectively. When both the integration scheme and real radar data were used to estimate cumulative precipitation for one day, their spatial distributions were similar.

A series of Eu3+ and Dy3+ singly and doubly doped Gd2MoO6 phosphors were synthesized with solid state reactions. The X-ray powder diffraction analysis of phosphors shows that substitution of Eu3+ and Dy3+ does not change the host structure of phosphors. The absorption spectra measurements show that un-doped Gd2MoO6 can absorb near ultraviolet light without any visible light emission. However, energy absorbed by Gd2MoO6 can be effectively transferred to doped Eu3+ and Dy3+ and makes them emit blue, yellow, and red light, respectively. White light can be obtained by combining blue, yellow, and red emission. The doping of Dy3+ plays a major role for the formation of white light. The introduction of Eu3+ can remarkably decrease the color temperature of the white light emission. The measurement of the temperature-dependent luminescent properties indicates that the phosphors present a good thermal stability. Our investigation indicates that Gd2MoO6:Eu3+,Dy3+ is a potential candidate for white light emitting diodes applications. It also provides a new sight for the achievement of white light emission.

The near-infrared persistent phosphors have attracted increasing attention due to the potential application in in vivo imaging. Exploring new materials to realize efficient near-infrared persistent luminescence is a goal of general concern. Ca14Zn6Ga10O35:Cr3+phosphor gives a near-infrared long persistent luminescence over 3 h with the 650–750 nm emission range after the short UV-irradiation. The afterglow behaviors such as the persistent luminescence, the trap depth distribution, the trap types and the underlying mechanism for persistent luminescence, were comprehensively surveyed by means of thermoluminescence methods and electron spin resonance spectra. In addition, Al dopant was introduced to redeploy the trap distribution in Ca14Zn6Ga10O35:Cr3+ phosphor. Compared with the well-known phosphor ZnGa2O4:Cr3+, Ca14Zn6Ga10O35:Cr3+ is proved to be a new NIR persistent phosphor potentially suitable for in vivo imaging due to its 650–750 nm emission range.

Li1.27Cr0.2Mn0.53O2 layered cathodic materials were prepared by a nanomilling-assisted solid-state process. Whole-pattern refinement of X-ray diffraction (XRD) data revealed that the samples are solid solutions with layered &alpha, NaFeO2 structure. SEM observation of the prepared powder displayed a mesoporous nature composed of tiny primary particles in nanoscale. X-ray photoelectron spectroscopy (XPS) studies on the cycled electrodes confirmed that triple-electron-process of the Cr3+/Cr6+ redox pair, not the two-electron-process of Mn redox pair, dominants the electrochemical process within the cathode material. Capacity test for the sample revealed an initial discharge capacity of 195.2 mAh&middot, g&minus, 1 at 0.1 C, with capacity retention of 95.1% after 100 cycles. EIS investigation suggested that the high Li ion diffusion coefficient (3.89 &times, 10&minus, 10&middot, cm2&middot, s&minus, 1), caused by the mesoporous nature of the cathode powder, could be regarded as the important factor for the excellent performance of the Li1.27Cr0.2Mn0.53O2 layered material. The results demonstrated that the cathode material prepared by our approach is a good candidate for lithium-ion batteries.

To overcome the shortcomings of single or multi-wavelength ultraviolet-visible (UV-Vis) absorbance spectroscopic methods, fluorescence spectroscopic or wet chemistry methods for chemical oxygen demand (COD) measurement, an online detection method based on multi-source spectral feature-level fusion was developed and evaluated. In this method, UV-Vis absorbance spectra (deuterium-halogen lamp as light source) and fluorescence emission spectra (405 nm wavelength laser as excitation source) were measured online by a spectrophotometer (PG2000-Pro-Ex, Ocean Optics). Discrete wavelet transform (DWT) and a successive projections algorithm (SPA) were utilized to realize signal de-noising and feature extraction on the two types of spectra, respectively. Feature-level fusion and least-square support vector regression (LS-SVR) were used to establish the COD measurement model. Through comparison of experiments and results, it is shown that the proposed method has a good performance on both noise tolerance and measurement accuracy.

In this paper, we study the vector scheduling game on two hierarchical identical machines, both in non-cooperative and in cooperative versions. When the private cost of jobs are maximum over components, we present the POS and its variants are 1, and the POA and its variants are 2. When the private cost of jobs are sum of components, we present the POS and its variants are 2, and the POA and its variants are 2. All the bounds given are tight.

This research mainly studies the factors influencing the efficiency of energy utilization. Firstly, by calculating Moran′sI and local indicators of spatial association (LISA) of energy efficiency of regions in mainland China, we found that energy efficiency shows obvious spatial autocorrelation and spatial clustering phenomena. Secondly, we established the spatial quantile autoregression (SQAR) model, in which the energy efficiency is the response variable with seven influence factors. The seven factors include industrial structure, resource endowment, level of economic development etc. Based on the provincial panel data (1998–2016) of mainland China (data source: China Statistical Yearbook, Statistical Yearbook of provinces), the findings indicate that level of economic development and industrial structure have a significant role in promoting energy efficient. Resource endowment, government intervention and energy efficiency show a negative correlation. However, the negative effect of government intervention is weakened with the increase of energy efficiency. Lastly, we compare the results of SQAR with that of ordinary spatial autoregression (SAR). The empirical result shows that the SQAR model is superior to SAR model in influencing factors analysis of energy efficiency.

Based on first-principles calculations, the electronic properties of n-type LaAlO3/SrTiO3 (LAO/STO) interfaces with LaO and AlO2 terminations were investigated. Thermodynamic analysis shows that the AlO2-terminated and LaO-terminated LaAlO3 surfaces are preferably formed under O-rich and O-poor conditions, respectively. We found that there are two polarization fields in heterostrucutres: one is the build-in polarization field induced by alternating LaO+1 and AlO2−1 layers and another is the strain-induced additional polarization field only existing in relaxed structures. The two polarization fields have a distinct influence on the electronic structures of interfaces. In this work, the influences of oxygen vacancies and cation defects at different sites on the conduction mechanism were analyzed in detail. The results indicate that point defects affect the electronic states of interfaces by two ways: providing or accepting electrons, and disturbing the internal polarization field. Approaching the interface, the defects tend to play the former role. Moreover, the calculations show that under O-rich condition, the reduced oxygen vacancies and the improved cation vacancies spontaneously formed at the interface deteriorate the n-type conductivity. The present results provide a theoretical guidance to utilize the effects of surface termination and point defects to tune the conductivity of perovskite heterostructures.