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Swidden agriculture is undergoing a rapid but overlooked transition and transformation in the tropics, complicating global carbon budgeting and sustainable livelihood assessment of swiddeners. Remotely sensed algorithms for accurately detecting swiddening practices have been slowly developed to generate annual updates on their dynamics. This is primarily because, using medium spatial resolution imagery (≥30 m), it is challenging to identify the exact boundary of swidden patches. Spectral-based approaches have by far dominated the detection and mapping of swidden agriculture, but the potential of Sentinel-2 has not been examined. To reconstruct annual information of swidden agriculture, a new Sentinel-2 three-band spectral index, i.e., the Normalized Difference Red, Near-infrared (NIR), and Shortwave-infrared (SWIR), or NDRII, has been developed to map freshly-opened swiddens in tropical regions. As Red (visible), NIR, and SWIR spectral band combinations (i.e., the VNIR-SWIR spectroscopy) are sensitive to vegetation-moisture variations and thermal anomalies caused by slash and burn in tropical uplands during the dry season, NDRII delineates exact patches of freshly opened swiddens. The latest 20-m map facilitates probing into the landscape patterns of newly opened swiddens and underlines their prevalence in Laos for the first time. Established within the VNIR-SWIR spectroscopy of Sentinel-2 and Landsat-8 Operational Land Imager, the NDRII algorithm contributes to reconstructing historical datasets of tropical swiddens via integrating state-of-the-art approaches that use temporally stacked observations with available VNIR/SWIR satellite imagery and further understanding the dynamics of landscape pattern and disturbance due to rapid transition and transformation.

Improving light-harvesting efficiency and suppressing interfacial charge recombination are of paramount importance to the development of Cu (II/I) redox shuttle-based dye-sensitized solar cells (DSSCs). Here, we present a rational molecular engineering on D-A-π-A organic sensitizers featuring with fluorenyl-substituted bulky donor (HY57, HY60, and HY61) for Cu (II/I) mediated DSSCs. By gradually enhancing conjugation and rigidity of the π-spacer and auxiliary acceptor moieties, the light-harvesting and electron-injection efficiencies can be simultaneously improved. The large size of fluorenyl-substituted arylamine donor together with abundant alkyl chains decorated on the molecular structures assist dense assembly of dye monolayer at surface of nanocrystalline TiO2, which largely suppress interfacial charge recombination losses. When applied in Cu (II/I) mediated DSSCs, the combination of an auxiliary acceptor of phenanthrene-fused-quinoxaline (PFQ) and a π-spacer of cyclopentadithiophene (CPDT) in dye HY61 results in a simultaneous enhancement in short-circuit current (JSC) and open-circuit voltage (VOC), thus improving the power conversion efficiency (PCE) from 7.3% for reference dye HY59 to 10.3% for HY61. This study demonstrates that rigid and fused building block is promising towards constructing highly efficient organic sensitizers.

AbstractThis study intended to investigate the injury severity of animal-vehicle crashes (AVCs) and identify the contributing factors from the perspective of animals. To achieve this objective, Bayesian random parameter probit regression model with endogenous variable was proposed with a case study application on two places in Inner Mongolia, China. First, from the perspective of animals, pooled probit regression model with endogenous variable was presented to address the endogeneity issue. Next, panel data model integrated with probit regression model with endogenous variable was presented in order to accommodate the heterogeneity issue due to unobserved factors within Bayesian framework, and to identify the significant influencing factors of injury severity. Results revealed that the endogenous variable (number of casualty) and vehicle type are significant factors for the animal injury severity. Meanwhile, it is demonstrated that there exists an endogeneity issue between injury severity and the number of casualty; while the panel data model integrated with Bayesian probit regression model accommodates the heterogeneity due to unobserved factors. The findings can contribute to the implementation of more reliable countermeasures to prevent the injury severity from drivers and animals in pastoral areas.

Pancreatic cancer remains as one of the most lethal malignancies. Resistance to conventional therapies has led to little improvement in the survival of pancreatic cancer patients over the past few decades. Immune-based treatment strategies for pancreatic cancer, such as immune-checkpoint inhibitors, therapeutic vaccines, and combination immunotherapies show promise. Many immunotherapies have been explored in clinical trials, but they have yet to show significant therapeutic effects. Nevertheless, immunotherapy is inevitably the future of pancreatic cancer cure. This article introduces the current research progress and bottlenecks of immunotherapy for pancreatic cancer and puts forward further optimization directions and solutions. We hope to provide a reference for the future use of immunotherapy for pancreatic cancer.

Abstract Background Peri-implantitis is the most difficult biological complication associated with dental implants, often requiring surgical treatments in advanced stages. This study compares the effectiveness of different surgical methods for peri-implantitis. Methods Randomized controlled trials (RCTs) of different surgical treatments for peri-implantitis were extracted from EMBASE, Web of Science, Cochrane Library databases, and PubMed systematically. Pairwise comparisons and network meta-analyses (NMA) were conducted to analyze the effect of surgical treatments on probing depth (PD), radiographic bone fill (RBF), mucosal recession (MR), bleeding on probing (BOP), and clinical attachment level (CAL). In addition, risk of bias, quality of evidence, and statistical heterogeneity of the selected studies were evaluated. A total of 13 articles were included in this study, involving open flap debridement (OFD), resective therapy (RT), and augmentative therapy (AT) with and without adjunctive treatments (laser therapy, photodynamic therapy, local antibiotics, phosphoric acid, and ozone therapy). Results AT improved RBF and CAL more than OFD, but does not outperform OFD in reducing peri-implant soft-tissue inflammation. AT, OFD and RT did not significantly alter the levels of MR. Addition of ozone therapy improved the effect of AT, but addition of photodynamic therapy did not affect PD reduction and CAL gain significantly. Similarly, adjuvant treatment with phosphoric acid during RT did not significantly change the outcome of BOP. Conclusions Within the limitation of this systematic review and NMA, AT was superior to OFD in improving peri-implantitis outcomes. While adjunct use of ozone therapy may further improve the efficacy of AT, the limited evidence supporting this combination therapy argues for cautionary interpretation of these results.

Layer dependence is an important aspect to properties of van der Waals materials. Here, the authors obtain layer dependent multiple polarization states in 3 R MoS2 and propose a generalized model to describe their ferroelectric switching processes.

Since 2014, the electric vehicle industry in China has flourished and has been accompanied by rapid growth in the power battery industry led by lithium-ion battery (LIB) development. Due to a variety of factors, LIBs have been widely used, but user abuse and battery quality issues have led to explosion accidents that have caused loss of life and property. Current strategies to address battery safety concerns mainly involve enhancing the intrinsic safety of batteries and strengthening safety controls with approaches such as early warning systems to alert users before thermal runaway and ensure user safety. In this paper, we discuss the current research status and trends in two areas, intrinsic battery safety risk control and early warning methods, with the goal of promoting the development of safe LIB solutions in new energy applications.

Heavy metal pollution in rivers and lakes arising due to rapid economic development has been extensively studied by various countries due to its direct impact on ecological health and human well-being. However, there is a lack of comprehensive and systematic reviews addressing the current research status of this subject. In this study, we conducted a visual metrological analysis of the literature from 2001 to 2021 using the Web of Science (WoS) and China National Knowledge Infrastructure (CNKI) citation databases. The results show that studies conducted in other countries initially outnumbered those in China; after 2010, China emerged as the foremost contributor. Furthermore, both the WoS and CNKI databases indicate active engagement of Chinese researchers through a significant proportion of published papers on metal research, with prominent contributions coming from institutions such as the Chinese Academy of Sciences (CAS) and University CAS. Nevertheless, Chinese research institutions still have relatively low total paper citation numbers and have yet to establish themselves as key players in international scientific research efforts. Additionally, core authors from different countries share substantial similarities in their research directions and focuses. Consistent research hotspots regarding heavy metals in rivers and lakes were identified across both databases, including heavy metal pollution, adsorption, human activities, water quality, and sediment.

Vision loss can occur when the cornea loses transparency or changes shape. The most effective treatment to restore vision is to use full or partial layers of donor cornea for corneal transplantation. However, there is a severe shortage of donor corneas worldwide, with more than 98.5% of patients with corneal blindness waiting for donor corneas. In addition, there exist some problems such as the possibility of infection, allotransplantation immunologic rejection, and other problems after corneal transplantation. Therefore, tissue-engineering corneas have been widely studied over the years as a viable alternative to donor corneas, with different materials and methods. And in nearly ten years, the research has had breakthrough progress. The ultimate goal of the research is to construct a full or partial tissue-engineering graft with good transparency, biocompatibility, and appropriate mechanical strength to repair, regenerate, or replace diseased corneas. This review discusses the research progress and existing problems about the most frequently studied natural biomaterials in recent years. These biomaterials include amniotic membrane, acellular cornea, collagen, and silk. In addition to the future research directions, other challenges related to the biomaterials discussed in this field are illustrated.

Maize crop lodging is a recurrent phenomenon which results in significant reduction of grain yield and quality in addition to the impediment of mechanical harvesting. The large-scale monitoring of maize crop lodging is important for production policy adjustment and agricultural insurance compensation. In this article, we derived a variety of features from multitemporal GaoFen-1 (GF-1) images before and after maize crop lodging. We screened the most sensitive features of the spectrum, texture, and vegetation index to monitor maize crop lodging. The recursive feature elimination method based on cross-validation and mutual information were compared to obtain the optimal feature combination for monitoring the lodging extents of maize crop. The random forest classifier was used to classify the lodging extents. The results showed that the most sensitive features of the spectrum, texture, and vegetation indices of lodging extents included the difference of reflectance in blue, green, and red bands, the difference of normalized difference vegetation index, the difference of ratio vegetation index, the difference of enhanced vegetation index difference, the difference of mean value of blue band, the difference of mean value of green band, and the difference of mean value of red band. The total accuracy of lodging extents classification was 87.50%, and the Kappa coefficient was 0.83 for testing samples. Based on multiple features derived from GF-1 images before and after lodging, the lodging extents of maize crop can be monitored on a large scale.

Gas production analysis during the thermal runaway (TR) process plays a crucial role in early fire accident detection in electric vehicles. To assess the TR behavior of lithium-ion batteries and perform early warning and risk estimation, gas production and analysis were conducted on LiNixCoyMn1-x-yO2/graphite and LiFePO4/graphite cells under various trigger conditions. The findings indicate that the unique gas signals can provide TR warnings earlier than temperature, voltage, and pressure signals, with an advanced warning time ranging from 16 to 26 min. A new parameter called the thermal runaway degree (TRD) is introduced, which is the product of the molar quantity of gas production and the square root of the maximum temperature during the TR process. TRD is proposed to evaluate the severity of TR. The research reveals that TRD is influenced by the energy density of cells and the trigger conditions of TR. This parameter allows for a quantitative assessment of the safety risk associated with different battery types and the level of harm caused by various abuse conditions. Despite the uncertainties in the TR process, TRD demonstrates good repeatability (maximum relative deviation < 5%) and can be utilized as a characteristic parameter for risk estimation in lithium-ion batteries.

Background Information regarding using a pig cadaver model for teaching purposes in dentistry is limited, especially for periodontal surgery procedures. The aim of this study was to assess the feasibility and efficacy of teaching crown lengthening surgical procedures using a prepared pig cadaver model. Methods Mandibles of slaughtered pigs with subgingival crown fracture defects on two premolars and two molars on each side were prepared as periodontal surgery teaching cases. A resident group (n = 20) and an instructor group (n = 18) participated in assessing the efficacy of the model by completing questionnaires before and after training sessions. Data was either assessed descriptively or analyzed statistically with Wilcoxon signed-rank test with the significance level at α = 0.05. Results Results revealed that all the knowledge points showed statistically significant improvements (p

Abstract Background A prospective cohort study was performed to evaluate whether the Optical Quality Analysis System (OQAS) can serve as a valuable additional indicator for appropriate posterior capsulotomy referral. Methods One hundred and five eyes from 96 patients undergoing capsulotomy were divided into precapsulotomy logMAR CDVA ≤0.1 group and logMAR CDVA > 0.1 group. CDVA, and the Visual Function 14 index (VF-14) score were estimated before and 1 month after capsulotomy. The objective scattering index (OSI) value was measured by using the OQAS. Posterior capsule opacification (PCO) severity was assessed with Evaluation of PCO 2000 (EPCO 2000) software. Results In logMAR CDVA > 0.1 group, the correlations of OSI, logMAR CDVA, EPCO score and VF-14 score were very strong preoperatively. In logMAR CDVA ≤0.1 group, preoperatively, OSI was correlated with logMAR CDVA (r = 0.451), EPCO score (r = 0.789), and VF-14 score (r = 0.852). LogMAR CDVA has weak correlation with VF-14 score (r = − 0.384) and EPCO score (r = 0.566). VF-14 score was correlated with EPCO score (r = − 0.669). In the logMAR CDVA ≤0.1 group, there was no significant difference in logMAR CDVA between precapsulotomy and postcapsulotomy (P > 0.05). In the two groups, all the other optical quality parameters were significantly improved after capsulotomy (P 0.1 group, the area under the curve of the ROC of the OSI was 0.996 (P = 0.000). In logMAR CDVA ≤0.1 group, the area under the curve of the ROC of the OSI was 0.943 (P = 0.000). Conclusions The OSI was useful for evaluating of PCO and prediction of beneficial capsulotomy. Especially for patients with slight PCO and better visual acuity, OSI is more valuable than CDVA and completely objective examination. Trial registration The study protocol was registered at the Chinese Clinical Trial Registry. Register: ChiCTR1800018842 (Registered Date: October 13th, 2018).

During the wafer fabrication procedure, abrasive machining occupies a large proportion in time and economic cost, mainly including grinding, lapping, and polishing. The third-generation semiconductor materials, represented by SiC, have the properties of high hardness, large brittleness, and strong chemical inertness, which make abrasive machining more challenging. To improve the machining efficiency and quality, this paper applied the smoothed particle hydrodynamics (SPH) method to simulate the machining behavior of single abrasive grain for SiC wafer. The micro-mechanical mechanisms of the main influencing parameters, such as velocity, depth, and angle, were studied in abrasive machining for SiC wafer. First, it is proved that using SPH coupled with a finite element to study the mechanical effects of abrasive machining for SiC wafer is a feasible and useful method. Then, the explanations for the beneficial effects of ultrasonic vibration-assisted machining, high-speed machining, and other abrasive machining are provided through the analysis of the simulated results. In addition, the optimization basis for parameters such as scratching velocity, scratching depth, and ultrasonic vibration frequency is obtained. This research provides a good insight into implying the micro-mechanical mechanisms of abrasive machining and achieving the optimization for the abrasive machining of hard-brittle wafer materials, which help avoid the shortcomings of experimental research and produce economic benefits.

Among the manufacturing methods of high performance gradient functional materials, laser additive manufacturing technology can achieve the materials with gradient microstructure and property through precisely controlling the powder feeding and corresponding process adjustment, providing a new way to prepare high performance gradient functional materials more conveniently and efficiently. The basic principles and classification of laser additive manufacturing technology for high performance gradient functional materials were introduced in this paper, and the research progress in manufacturing high performance gradient functional materials by laser additive manufacturing technology at home and abroad was summarized. Furthermore, the shortcomings of this research field in material selection, process optimization and process monitoring were proposed, and its future research directions, such as the establishment of standard systems, in-depth theoretical research and the development of new manufacturing systems, were prospected, which provide guidance for the research of laser additive manufacturing technology for high performance gradient functional materials.

Abstract. Background. There is limited evidence of the effects of local anesthesia (LA) on outcomes of non-surgical periodontal treatment (NSPT), in particular among the Chinese. This retrospective cohort study aimed to evaluate the effects of LA on short-term treatment outcomes of NSPT and to determine under what circumstances LA should be prescribed to improve these outcomes. Methods. Data from periodontal examinations of 3980 patients were used. The data were from 3-month re-evaluation records of an electronic periodontal charting record system in the Department of Periodontology of Peking University School and Hospital of Stomatology from June 2008 to January 2015. Descriptive analyses included changes in probing depth (PD) and the Mazza bleeding index (BI). Two-level (patient and tooth) logistic regression models and three-level (patient, tooth, and site) linear regression models were constructed to analyze the influence of LA on PD for all teeth/sites and teeth/sites with an initial PD ≥ 5 mm. Decreases in PD and BI at sites under LA using the initial PD were also compared. Results. A significantly higher mean decrease in PD after NSPT was found in the LA group than in the no local anesthesia (NLA) group (0.98 vs. 0.54 mm, t = 24.12, P 1 and BI > 2) for all teeth (16.7% vs. 13.8%, t = 3.75, P

Abstract Background Nasopharyngeal carcinoma (NPC) is a common malignant tumor. Ten-eleven translocation (TET) protein 2 (TET2), an evolutionarily conserved dioxygenases, is reported to be involved in various malignant tumor developments. Here, we aim to investigate the effect of TET2 on NPC progress in vitro and in vivo, and its detailed underlying mechanism. Methods Real-time PCR and western blotting were used to determine the expression levels of TET1/2/3 in NPC cell lines. The effects of TET2 on NPC progression were evaluated using CCK8 and invasion assays in vitro. Proteins interacted with TET2 in NPC cells were detected by immunoprecipitation and mass spectrometry. The effects of TET2 or pyruvate kinase, muscle (PKM) on glycolysis in NPC cells were examined by detecting glucose uptake and lactate production. The effects of TET2 on NPC progression were evaluated using xenograft tumor model in vivo. Results TET2 expression was decreased in NPC cells, and TET2 overexpression inhibited proliferation and invasion of NPC cells, which is independent on TET2’s catalytic activity. In mechanism, TET2 N-terminal domain interacts with PKM in cytoplasm to prevent PKM dimers from translocating into nucleus, suppressing glycolysis in NPC cells, thereby inhibiting proliferation and invasion of NPC cells. Moreover, using xenograft tumor model, we found that TET2 knockout promoted NPC progression and decreased survival rate. However, administration with the inhibitor of PKM, shikonin, decreased the tumor volume of TET2-cas9 group, and increased the survival rate. Conclusion TET2 suppresses NPC development through interacting with PKM to inhibit glycolysis.

The effective assessment of drivers' driving capability under the condition of an advanced driver assistance system is of great significance to the precise switching of driving rights between human and machine and the promotion of the development of man-computer collaboration. In this study, real-time collected warning data from bus driver state monitoring system (DSMS) and advanced driver assistance system (ADAS) were utilized to determine the drivers' comprehensive driving capability indicators. The information utility and interaction of the indicators were considered, and an integrated weight method based on standard deviations was proposed. This method was used to combine the entropy weight method and improved analytic network process (ANP), to evaluate the drivers' comprehensive driving capability under man-computer cooperative driving conditions in real time. The results show that the entropy weight method and improved ANP algorithm have good consistency and are significantly correlated and that the integrated weight method is effective and dependable. The top four indicators in the integrated weighting results were eye closure (0.241), yawn (0.210), rapid deceleration (0.186), and lane departure (0.159). Drivers' comprehensive driving capability scores were concentrated in the score range of 1 to 6, with the lowest scores in zones A and B for stages 2, 11 and 21. Therefore, it is necessary to further explore the relationship between driver behavior, vehicle status and road traffic environment within the score range of 1 to 6 so that the man-computer interaction can be optimized and the driver's comprehensive driving capability can be improved.

Metal halide perovskites (MHPs) are attracting ever‐growing interest across diverse optoelectronic subdisciplines. Yet, the physical mechanism underlying photoexcitation and subsequent photocarrier dynamics remains poorly understood, due to the apparent spectroscopic diversities observed for any certain MHP. Here, diverse spectroscopic characteristics, including static spectral line‐shapes and time‐resolved photoluminescence (TRPL) traces shown by polycrystalline versus single‐crystalline CH3NH3PbBr3 perovskites, are restudied. Key photophysical merits, including exciton binding energy (EB), Sommerfeld factor (ξ), and Urbach energy (EU) that account for the diversities, are discussed within the established framework of semiconductor optics. The value of ξ, which increases with EB, determines how much the interband absorption is enhanced beyond that expected for free carriers. The intrinsic band‐edge luminescence is identified, with its asymmetric spectral line‐shape linked to EU via the van Roosbroeck–Shockley relation. Excited phase evolution, accompanied by rapid electron–hole (e–h) pairs dissociation and subsequent occurrence of e–h plasma, is indicated by the two‐stage TRPL traces that are only observable for high‐quality single crystals. With all the spectroscopic analysis and interpretations rooted in the established semiconductor optical theorems, the mechanistic merits revealed in this study are informative for plausible identification between the interband and excitonic photophysical processes of MHPs.

Esophageal and tracheal foreign body ingestion trigger common pediatric emergencies. In this case report, we describe a pediatric patient with simultaneous tracheal and esophageal obstruction caused by foreign bodies. A child aged 2 years and 1 month swallowed a pair of metallic magnetic beads at the same time; one bead entered the trachea and the other bead entered the esophagus. We suspected that the two magnetic beads were mutually attracted and thus became trapped in their respective lumina. The tracheal foreign body was uneventfully removed; this dislodged the esophageal foreign body, which was then excreted. There were no serious complications in the present case, but parents and medical personnel should be mindful of the potential hazards associated with ingestion of multiple magnetic foreign bodies. A high index of suspicion is appropriate. Investigations must be carefully planned. Treatment should not be delayed; the consequences of delay may be serious.

With the development of basic theoretical research and equipment, laser additive manufacturing technology is widely used in the manufacture of large complex components. However, the internal stress in laser additive manufacturing process tends to result in distortion and cracking. Stress and deformation control has become an urgent issue in laser additive manufacturing process. In this paper, research progress of residual stress in laser additive manufacturing was reviewed from various aspects such as residual stress forming mechanism, test methods, control measures. Furthermore, the main problems and research directions were proposed for the research of stress and deformation control technology, which provides guidance for the research of "shape control" in laser additive manufacturing.

Zn-Al-Mg alloy coating, the most promising protective steel coating of the 21st century, is widely employed in construction, automotive, and other fields, due to its high surface and edge corrosion. In recent years, with the increasing demand for Zn-Al-Mg coating, a series of basic studies on Zn-Al-Mg coating materials has been carried out by foreign scholars, making significant progress and achievements. Simultaneously, the gap in the galvanizing industry between domestic and international has been expanding year by year. In order to gradually reduce gradually this gap with foreign countries, it is necessary to summarize and review the research achievements of foreign researchers. In this paper, the research progress into high corrosion resistant Zn-Al-Mg hot dip coatings was reviewed from the perspective of interfacial reactions in pots, coating structures, corrosion mechanisms of surface and cut edges, as well as corrosion product types of Zn-Al-Mg coatings. According to the range of Al content, laboratory and commercial Zn-Al-Mg coatings are divided into three types: "low-aluminum, " "medium-aluminum, " and "high-aluminum" coatings. There are differences in these coatings, including growth kinetics in the intermetallic compound layers of the different types of coating. In order to control the thickness of the coating, reasonable immersion time and temperature should be controlled. There are also differences in the solidification structures of the three types. Primary Al or Zn crystal, Zn/MgZn2 binary eutectics, and Zn/MgZn2/Al ternary eutectics would form in "low-aluminum" and "medium-aluminum, " while Al-rich dendrites, an intergranular Zn-rich phase, a Mg2Si phase, and a MgZn2 phase would occur with "high-aluminum" coatings. During surface corrosion in "low-aluminum" or "medium-aluminum, " the MgZn2 phase is ionized first, giving rise to a dense corrosion product to inhibit corrosion, such as basic zinc salt (BZS) or layered double hydroxide (LDH). Meanwhile, in the cut edge, a self-healing phenomenon occurs; the proposed explanation in this paper for this is Mg-containing corrosion product flowing or pH changing. However, there are some disputed aspects that need further study. In the hot dipping process, the intermetallic compound thickness should be controlled by the interfacial reaction at the steel/liquid melts through changing the molten bath temperature and holding time. The influence of Mg2Zn11 phase and MgZn2 on the corrosion resistance of Zn-Al-Mg coating is also controversial, so that the microstructure of Zn-Al-Mg coating needs further investigation for corrosion. Furthermore, a kinetic model of the corrosion process should be established to discover the controlling factors in the corrosion reaction, so that the life of the coating can be extended.

A developed and verified thermodynamic model based on the atom and molecule coexistence theory (AMCT) is employed to predict activities relative to pure liquids in standard state in Mg-Al, Mg-Zn, Al-Zn and Mg-Al-Zn melts through the calculated mass action concentrations of structural units, i.e., Ni. According to AMCT, Ni can be extrapolated and calculated by the chemical equilibrium constant of a structural molecule, i.e., Ki, in the Mg-Al-Zn ternary system and binary subsystems. In this paper, the standard Gibbs free energy function, for reported activities and mixing thermodynamic properties in Mg-Al, Mg-Zn and Al-Zn melts, was regressed and optimized. The results showed that Ki and Ni were deduced by Gibbs free energy function at the studied temperature. The results of calculating thermodynamic properties in the full composition range for liquid Mg-Al-Zn from 880 to 1100 K, as well as Mg-Al from 923 to 1073 K, Mg-Zn from 880 to 973 K and Al-Zn from 1000 to 1073 K, are presented in the paper by coupling with Ni and AMCT. An excellent agreement is noticed between the calculated values of this study and measured thermodynamic data from the references, suggesting that the AMCT can be well applied to describe and predict the activities of the Mg-Al-Zn system and its subsystems.

In the case of preheating and non-preheating, the rapid prototyping system of high-power fiber laser and electromagnetic induction heating equipment was used to fabricate 12CrNi2 alloy steel. The microstructure of the molded parts was observed under a scanning electron microscope, and the hardness test of different parts was conducted using the Victorinox hardness tester. The tensile properties in different directions were tested using the universal material testing machine. This study investigated the effect of preheating on the microstructure, hardness, and tensile properties of laser melting deposited 12CrNi2 alloy steel in different directions. The obtained results show that the microstructure of the single-channel molten pool without preheating is lath martensite, and the molten pool of block-shaped forming parts is tempered martensite and bainite mixed structure. No obvious structural difference between XOZ and YOZ sections is observed. However, the overall hardness of the YOZ cross section is larger than that of the XOZ cross section. Large-scale macroscopic crack defects appear in both sections, and the mechanical properties are poor. Under preheating conditions, bainite transformation occurs in the molten pool because of the decrease in the temperature gradient. The single-channel molten pool shows an excellent bainite structure. No tempered martensite transformation in the molten pool of block-shaped forming parts, mainly granular bainite, is observed. Cross-sectional hardness distribution is more uniform with preheating than without preheating. High tensile strength and low plasticity are detected in the tensile and overlap directions. The tensile strength is up to 1189 MPa, the yield strength is 951 MPa, and the elongation is only 2.8%. No obvious anisotropy in performance is observed. Preheating can reduce the temperature gradient in the molten pool, reduce the thermal stress, effectively control the crack defects, promote the homogenization of the microstructure, reduce the anisotropy of the microstructure and properties, and improve the mechanical properties of the alloy steel forming parts.

Based on acoustoelastic theory, stress measurement of laser cladding coating with Rayleigh wave was investigated.The acoustoelastic formula for evaluation of stress in laser cladding coating was simplified by means of Taylor series expansion method.Combined with the static load tensile test, acoustoelastic coefficients were determined.The results show that the variation rate of Rayleigh wave signal velocity in Fe314 alloy coating increases linearly with the increase of stress.When tensile stress is greater than 495MPa, the variation rate of Rayleigh wave signal velocity does not change linearly any more.Based on the analysis of ultrasonic propagation theory and microstructure of laser cladding coating, the changing rule of acoustoelastic curve and its influence mechanism on stress measurement were analyzed, the inhomogeneous deformation of anisotropic laser cladding coating is the main cause of the "wave-type" fluctuation of acoustoelastic curve in high stress stage.Results show that anisotropic tissue effect can affect the result of stress measurement;the penetration in laser cladding layers can be ignored. By fitting the acoustoelastic curve, anisotropic tissue effect factor is determined.The experimental results show the maximum relative error in stress measurement is 4.4%, the method can realize the nondestructive evaluation of the stress in laser cladding coating.

Abstract Background The distribution pattern and knowledge structure of choroidal neovascularization (CNV) was surveyed based on literatures in PubMed. Methods Published scientific papers about CNV were retrieved from Jan 1st, 2012 to May 31st, 2017. Extracted MeSH terms were analyzed quantitatively by using Bibliographic Item Co-Occurrence Matrix Builder (BICOMB) and high-frequency MeSH terms were identified. Hierarchical cluster analysis was conducted by SPSS 19.0 according to the MeSH term-source article matrix. High-frequency MeSH terms co-occurrence matrix was constructed to support strategic diagram and social network analysis (SNA). Results According to the searching strategy, all together 2366 papers were included, and the number of annual papers changed slightly from Jan 1st, 2012 to May 31st, 2017. Among all the extracted MeSH terms, 44 high-frequency MeSH terms were identified and hotspots were clustered into 6 categories. In the strategic diagram, clinical drug therapy, pathology and diagnosis related researches of CNV were well developed. In contrast, the metabolism, etiology, complications, prevention and control of CNV in animal models, and genetics related researches of CNV were relatively immature, which offers potential research space for future study. As for the SNA result, the position status of each component was described by the centrality values. Conclusions The studies on CNV are relatively divergent and the 6 research categories concluded from this study could reflect the publication trends on CNV to some extent. By providing a quantitative bibliometric research across a 5-year span, it could help to depict an overall command of the latest topics and provide some hints for researchers when launching new projects.

Silicon carbide (SiC) devices have become one of the key research directions in the field of power electronics. However, due to the limitation of the SiC wafer growth process and processing capacity, SiC devices, such as SiC MOSFET (Metal-oxide-semiconductor Field-effect Transistor), are facing the problems of high cost and unsatisfied performance. To improve the precise machinability of single-crystal SiC wafer, this paper proposed a new hybrid process. Firstly, we developed an ultrasonic vibration-assisted device, by which ultrasonic-assisted lapping and ultrasonic-assisted CMP (chemical mechanical polishing) for SiC wafer were fulfilled. Secondly, a novel three-step ultrasonic-assisted precise machining route was proposed. In the first step, ultrasonic lapping using a cast iron disc was conducted, which quickly removed large surface damages with a high MRR (material removal rate) of 10.93 μm/min. In the second step, ultrasonic lapping using a copper disc was conducted, which reduced the residual surface defects with a high MRR of 6.11 μm/min. In the third step, ultrasonic CMP using a polyurethane pad was conducted, which achieved a smooth and less damaged surface with an MRR of 1.44 μm/h. These results suggest that the ultrasonic-assisted hybrid process can improve the precise machinability of SiC, which will hopefully achieve high-efficiency and ultra-precision machining.

Based on Lcr wave acoustoelastic theory, the influence mechanism of blind-hole on stress evaluation with Lcr wave was discussed. Combined with equivalent method, the blind-holes with different diameters were preset, the difference in time of flight between Lcr wave was calculated by cross correlation coefficient function, the Lcr wave acoustoelastic coefficient was determined with linear fitting function, the influence mechanism of blind-hole diameter on Lcr wave acoustoelastic coefficient was clarified based on the elastic plastic deformation theory and stress concentration theory of hole. The results show that when the diameter of blind-hole is different, the change rule of the difference in time of flight between Lcr wave is basically the same as stress increases, the difference in time of flight between Lcr wave increases linearly as stress increases, while the nonlinear feature is also gradually obvious, the maximum stress in linear stage is less than the yield strength of specimen, the Lcr wave acoustoelastic coefficient decreases gradually as blind-hole diameter increases, and it tends to be constant. The analysis shows that the stress concentration is seen as the main reason for above results, anisotropic structure of specimen and blind-hole depth are also the important reasons for that.

The temperature field of FeCrNiCu alloy forming layers of continuous wave(CW) and pulsed laser remanufacture was analyzed using the non-contact infrared thermometer.The general rule of temperature field distribution of molten pool and heat-affected zone of the two modes was obtained. The pulsed laser process superiority in heat input, forming deformation control and reducing the temperature in molten pool and heat-affected zone was vilidated. The results show that during pulsed laser forming the peak temperature in the heat-affected zone is 730.4-810.5℃,the peak temperature in the molten pool is 998.7-1383.4℃,which are all obviously lower than the same process of the CW mode; the temperature-rise rate and cooling rate of pulsed laser are higher, which is helpful to the forming of fine grain structures and good mechanical performance; the forming experiment also further verifies more narrow heat-affected zone in pulsed laser process.

A compliant bistable mechanism is a device that can maintain two distinct positions without power input. There is a wide range of applications in the field of MEMS and mechanical transmission. Usually,the energy method is used for judging the steady state of compliant mechanism,but the driving characteristic of compliant mechanism can’t be analyzed. A new method for the steady state analysis of four bar mechanism based on dynamics is presented to analyze the driving characteristic of four bar mechanism with only a compliant joint.And according to the drive characteristic curve,the steady state characteristics of the flexible mechanism are judged. Firstly,the pseudo- rigid body model of the compliant four bar mechanism is established by using pseudo- rigid body method,and the dynamic equations are listed by using the Lagrange equation of the second kind. The change curve of driving force is calculated when the active member is rotated 360°. Then the corresponding flexible four bar mechanism model is established in ADAMS,and the simulation results are compared with the results of the dynamics calculation to verify the accuracy of the dynamics model. Finally,a numerical example is given to compare the dynamics analysis method with the traditional energy method. The results show that the dynamics analysis method is effective. At the same time,the critical value of the driving force in the process of steady state and non steady state position conversion are obtained,and a new method for the design of the flexible steady state mechanism is provided. At the same time,based on the dynamics characteristic of bistable state,the bistable switches and sensor can be designed and used.

ZnO nanorods and RGO/ZnO nanorods composites were prepared by hydrothermal method. The influence of RGO content on the photocatalytic activity of RGO/ZnO nanorods composites was studied. ZnO nanorods and RGO/ZnO nanocomposites were characterized by X-ray diffraction (XRD), field emission electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance UV-visible absorption spectroscopy techniques. The results show that RGO/ZnO samples are synthesized successfully. With different additions of GO, the RGO/ZnO samples obtained exhibit different absorption characteristics in visible light region. The photocatalytic results of using methyl orange (MO) as the simulated pollutant show that RGO/ZnO nanorods composites exhibit high degradation efficiency under UV-Vis light illumination. The highest photocatalytic performance is obtained for RGO/ZnO composites when the mass ratio of RGO to ZnO is 3%. MO is almost completely degraded in 120min. RGO/ZnO also shows the visible-light-driven photocatalytic activity under visible light illumination (λ>400nm), and the maximum MO degradation efficiency in 180min can reach 26.2%, meanwhile, RGO/ZnO samples exhibit good photostability.

Objectives To map publication trends and explore research hotspots of retinal vein occlusion (RVO) study. Methods Based on Web of Science Core Collection (WoSCC), a bibliometric analysis was carried out. The knowledge map was constructed by VOSviewer v.1.6.10 to visualize the annual publication number, the distribution of countries, international collaborations, author productivity, source journals, cited reference and keywords in this field. Results A total of 2,135 peer-reviewed papers were retrieved on RVO from 2009 to 2018. The United States ranks highest among countries with the most publications and the most active institution was Kyoto University. Noma H contributed the most publications in this field. Retina—The Journal of Retinal and Vitreous Disease was the most prolific journal in RVO research. The top cited references mainly presented anti-VEGF medications on the management of RVO. The keywords formed six clusters: (1) Risk factors and pathogenesis of RVO; (2) Metabolismof RVO; (3) Therapeutic use of corticosteroids on RVO; (4) Diagnostic methodsof RVO; (5) Management of macular edema secondary to RVO (6) Anti-VEGFtreatment of RVO. Conclusions The six major research hotspots could provide an insight into RVO research and valuable information for researchers to identify potential collaborators and partner institutions.

Nasopharyngeal carcinoma (NPC) is the most common type of malignancy of the neck and head in Southeast Asia and North Africa. Long noncoding RNA (LncRNA) Differentiation antagonizing nonprotein coding RNA (DANCR) has been reported to exert oncogenic functions in various malignant tumors. However, whether DANCR is involved in NPC tumorgenesis and its underlying mechanisms are still unknown. In the current study, we investigated the expression and biological functions of DANCR in NPC cells and found that DANCR is highly expressed in NPC cells and IL-6 stimulation upregulates DANCR expression through an STAT3-dependent manner. Besides, DANCR knockdown attenuates IL-6-induced proliferation and invasion of NPC cells. Furthermore, DANCR specifically interacts with STAT3 to promote STAT3 activation in NPC cells. Moreover, DANCR knockdown evidently decreases IL-6 induced the association between STAT3 and JAK1 in NPC cells. In addition, we also found that DANCR also indirectly binds to JAK1 through interacting with STAT3 under IL-6 stimulation in NPC cells. Taken together, the present study for the first time demonstrates that DANCR, acting as an oncogene in NPC, promotes NPC progression by interacting with STAT3 and enhancing JAK1 binding to STAT3 to strengthen IL-6/JAK1/STAT3 signaling, suggesting that it may be a potential target to be used as a novel strategy to develop NPC therapeutics.

Objective. To introduce the combined laser technique, argon laser peripheral iridoplasty (ALPI) and argon laser pupilloplasty (ALPP), in the management of medically unresponsive acute primary angle closure (APAC). Design. Retrospective study. Methods. We retrospectively reviewed the records of 23 patients (27 eyes) with APAC, who were applied ALPI and ALPP when traditional treatment failed. The visual acuity and intraocular pressure (IOP) were monitored before surgery and at 1, 2, 12, 24, and 48 h after surgery. Additionally, the angle-opening status was monitored before surgery and 48 h after the treatment by using an ultrasonic biological microscope (UBM), and the presurgical and postsurgical cornea edema statuses were observed by using a slit lamp. We also documented the complications of laser treatment. Results. For the ALPI + ALPP laser-effective group, the presurgical IOP was 52.1 ± 9.3 mmHg and the postsurgical IOP was 37.6 ± 10.9 mmHg (1 h), 28.4 ± 12.4 mmHg (2 h), 19.9 ± 9.0 mmHg (6 h), 16.8 ± 7.3 mmHg (12 h), 15.9 ± 5.9 mmHg (24 h), and 14.9 ± 5.0 mmHg (48 h), with statistically significant differences (p

Antiferromagnetic (AFM) domains in ultrathin CoO(001) films are imaged by a wide-field optical microscopy using magneto-optical birefringence effect. The magnetic origin of observed optical contrast is confirmed by the spin orientation manipulation through exchange coupling in Fe/CoO(001) bilayer. The finite size effect of ordering temperature for ultrathin single crystal CoO film is revealed by the thickness and temperature dependent measurement of birefringence contrast. The magneto-optical birefringence effect is found to strongly depend on the photon energy of incident light, and a surprising large polarization rotation angle up to 168.5 mdeg is obtained from a 4.6 nm CoO film with a blue light source, making it possible to further investigate the evolution of AFM domains in AFM ultrathin film under external field.