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An approach to aberrarone, an antimalarial diterpenoid natural product with tetracyclic skeleton is reported. Key to the stereoselective preparation of the 6-5-5 tricyclic skeleton includes the mediation of Nagata reagent for constructing the C1 all-carbon quaternary centers and gold-catalyzed cyclopentenone synthesis through C–H insertion.

On 21 May 2021, an Mw 7.4 earthquake occurred in Maduo County, Qinghai Province, China. A dense network of high-rate (1 Hz) Global Navigation Satellite System (GNSS) stations around the epicenter provided one of the most complete recordings of GNSS kinematic displacements in Tibet to date. We used these data retrospectively to test a prototype earthquake early warning (EEW) system. Here, we present the results of that test, in which the EEW system archived high-rate GNSS displacement streams, and then used them to track evolving magnitude and slip. The geodetic module in the EEW system issued the first alert 34 s after the earthquake onset. The first alert had a moment magnitude (Mw) of 6.65, which then increased until reaching a stable value (Mw 7.4) 61 s after the earthquake onset. Testing results show good agreement with rapid GNSS displacements and postprocessed GNSS displacements; moreover, the rapid finite-fault inversion is consistent with postinversion magnitude and rupture dimensions. Our findings confirm the viability and usefulness of this EEW system in quasi-real-time magnitude estimation and finite-fault slip inversion.

Identifying the location of fault creep, quantifying its rate and spatiotemporal variation are critical for seismic hazard assessment. Interferometric Synthetic Aperture Radar (InSAR) observations have identified substantial shallow aseismic slip along the Kangding segment of the Xianshuihe fault, with rates reaching up to ~20 mm/yr. Due to the Kangding earthquake in 2014, whether the aseismic slip along the segment reflects the secular creep, afterslip effects, or their joint contribution remains unresolved. In this study, we characterize the temporal evolution of shallow creep rates on the fault plane, using both ascending and descending Sentinel-1A/B data spanning 2014-2021. The results indicate most of afterslip ends within two years following the 2014 Kangding earthquake. With the afterslip disappearing, the number of earthquakes distributed in the afterslip zone gradually decreases. We then identify a ~15 km-long creeping segment with a steady slip rate ~13 mm/yr between Huiyuan temple and Jinlong temple. In addition, a series of seismic clusters located within the creeping segment potentially bear the signature of repeating earthquakes, although we must confirm this hypothesis. Considering that the ruptures of historical strong earthquakes do not fully penetrate the creeping segment, it might act as a barrier to arrest the next earthquake rupture.

The ferrite content of austenitic stainless steel welds seriously affects to perform stainless steel welds. Keeping the ferrite content at the lower limit can reduce the thermal crack sensitivity o...

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The generated stochastic slip ruptures.

Cochlearol B and Ganocins A-C are polycyclic meroterpenoids isolated from Ganoderma cochlear with renoprotective effect and as AChE inhibitor, respectively. Using a strained cyclobutane as overbred intermediate, a unified synthesis of the four natural products is reported, including a scalable eight-step synthesis of cochlearol B. The synthesis of cochle-arol B features a [2+2] photocycloaddition to forge a highly substituted cyclobutane, and the first-generation synthesis of ganocin A features a complex carbocation rearrangement sequence initiated by an epoxide-opening. Moreover, a bio-inspired unprecedent oxidative cleavage of cyclobutane ring enables the second-generation synthesis of ganocin A ac-complished concisely in 10 steps. Furthermore, ganocins B and C were obtained after decarboxylation and a one pot re-action of -elimination, dehydration and deprotection. Our synthesis adds insight to the plausible non-enzymatic biogen-esis of these natural products.

Austenite isothermal transformation curve (IT) of steel, also known as time-temperature-transformation curve (TTT) is an very important basic data for the heat treatment process design of steel. Traditionally, obtaining TTT information on metal mainly depends on experiments, so there are problems such as data dispersion, large errors, and inconvenient access in use. Using artificial intelligence and machine learning technology, the TTT curve of steel can be predicted with limited experimental data. Taking the authoritative data collected as training samples, the TTT curve of alloy structural steel was predicted based on a variety of machine learning algorithms.. Alloying element category, austenitizing temperature, phase transformation time are taken as input characteristics, and 10 kinds of transformation characteristics are taken as output targets. Correlation coefficient (R), and error analysis (RMSE, MAE) are used to evaluate and finalize the model, and the best algorithm is selected to form a combined-machine-learning algorithm (CML), and predict the TTT curve. Take the application of CML multi-model prediction method in 40Cr, 38CrMoAl, 35SiMn, and 20Mn2, and the predicted results reflect that the CML model has high prediction ability and good generalization.

Background: Cancer threatens human health seriously. Diagnosing cancer via gene expression analysis is a hot topic in cancer research. Objective: The study aimed to diagnose the accurate type of lung cancer and discover the pathogenic genes. Methods: In this study, Affinity Propagation (AP) clustering with similarity score was employed to each type of lung cancer and normal lung. After grouping genes, sparse group lasso was adopted to construct four binary classifiers and the voting strategy was used to integrate them. Results: This study screened six gene groups that may associate with different lung cancer subtypes among 73 genes groups, and identified three possible key pathogenic genes, KRAS, BRAF and VDR. Furthermore, this study achieved improved classification accuracies at minority classes SQ and COID in comparison with other four methods. Conclusion: We propose the AP clustering based sparse group lasso (AP-SGL), which provides an alternative for simultaneous diagnosis and gene selection for lung cancer.

Near-infrared light-emitting diodes (NIR-LEDs) have been a potential candidate in food composition analysis, tempera-ture and security monitoring, biometrics, and medical applications. To realize t...

Peak ground displacement (PGD) and peak ground velocity (PGV) are critical parameters during earthquake early warning, as they can provide rapid magnitude estimation before rupture end. In this study, we used the high-rate Global Navigation Satellite System (GNSS) data from 55 continuous stations to estimate the magnitude of the 2021 Maduo earthquake in western China. We used the relative positioning method and variometric approach to acquire real-time GNSS displacement and velocity waveforms, respectively. The results showed the amplitude of displacement and velocity waveforms gradually decreased with increasing hypocentral distance. Our results showed that the fluctuation of PGD magnitudes over time is smaller than that of PGV magnitudes. Nonetheless, the earthquake magnitudes estimated from both methods were consistent with their counterparts (Mw 7.3) reported by the United States Geological Survey (USGS). The final magnitude estimated from the PGD and PGV methods were Mw 7.25 and Mw 7.31, respectively. In addition, our results highlighted how the number of high-rate GNSS stations could influence the stability and convergence time of magnitude estimation.

Facial expression recognition has long been a challenging task in the computer field. Most of the existing facial expression recognition methods are the extraction of facial features, but these methods emphasize that the neural network should pay attention to some key features of the expression, such as eyes, nose, and mouth. These methods ignore some minor features that also affect expression recognition, such as facial texture and other features. This paper proposes an efficient Shuffle Attention Supplement (SAS)-Net attention module to solve some minor facial feature extraction problems. SAS-Net mainly combines the feature map before entering the SAS attention module and the attention feature map formed after aggregation of the submodules in the SAS attention module. This method makes the feature map serves as an information supplement to the feature map aggregated by the sub-modules of the SAS attention module, and strengthens the connection with the minor features of the feature map instead of only focusing on the salient features. This paper will combine the ResNet network with SAS attention module and ResNet network with Shuffle Attention (SA) module to experiment on the CK+ dataset, with the accuracy of 98.9836%. The results indicate that the proposed method has the potential to improve the performance of facial expression recognition.

An intramolecular formal [3 + 2] cationic cycloaddition between benzylic carbocation and styrene was developed for the total synthesis of codonopiloneolignanin A. Further study shows benzocycloheptene as a good substrate for 1,3-dipolar cycloaddition, and a model study toward cephalocyclidine A skeleton was reported.

High-performance and thermally stable phosphors play an important role in high-quality white light-emitting diode (pc-WLED) lighting. In this work, we proposed a cation substitution strategy to imp...

A novel orange-yellow-emitting Ba3Y4O9:Bi3+ phosphor (550 nm) has been firstly discovered. Meanwhile, we report isomorphic Ba3Lu4O9:Bi3+ with green emission (526 nm). Based on the cation substitution strategy, a series of Ba3Y4−wLuwO9:Bi3+ (0 ≤ w ≤ 4) solid solution phases are successfully constructed, realizing consecutive photoluminescence control from orange-yellow to green light. The occurrence of site migration of Bi3+ ions from Y2/Lu2 and Y4/Lu4 to Y1/Lu1 and Y3/Lu3 sites results in the blueshift of Ba3Y4−wLuwO9:Bi3+ (0 ≤ w ≤ 4), which is confirmed by the linear increase of PL intensity I(1+3)/I(2+4) with the substitution of Lu3+ ions for Y3+ ions. Besides, the improved thermal stability of Ba3Y4−wLuwO9:Bi3+ (0 ≤ w ≤ 4) with the substitution of Lu3+ for Y3+ originates from the better structure rigidity. The fabricated white light-emitting diodes (WLEDs) exhibit excellent warm white light, indicating that the as-prepared Ba3Y4−wLuwO9:Bi3+ (0 ≤ w ≤ 4) phosphors can act as a green to yellow emitting component in WLED lighting.

Non-rare earth doped oxides with red emission are one of the current research hotspots for achieving the warm white light range in the phosphor converted white light emitting diodes (pc-WLEDs) field. In the current work, a novel Mn4+-activated La2CaHfO6 red phosphor is reported for the first time and its crystal structure is analyzed by Rietveld refinement. The photoluminescent properties of La2CaHfO6:Mn4+ are investigated in detail with the help of diffuse refletance spectroscopy, photoluminescence spectroscopy, and temperature-dependent PL spectroscopy. Based on the diffuse refletance spectra, the calculated optical band gap for La2CaHfO6 is 4.9 eV, indicating that La2CaHfO6 could be a suitable host for activators' doping. Under 380 nm near-ultraviolet (n-UV) light excitation, the as-prepared La2CaHfO6:Mn4+ displays intense red emission centered at 693 nm. Through an accurate calculation of Dq/B (2.47) and nephelauxetic effect β1 (0.949), the origination of strong crystal field (CF) and deep-red emission is demonstrated. By combining the representative La2CaHfO6:0.002Mn4+, blue BAM:Eu2+, and green (Ba,Sr)2SiO4:Eu2+ phosphors with a 380 nm UV chip to fabricate the pc-WLEDs device, a white light is obtained with low correlated color temperature (CCT = 5165 K) and high color rendering index (Ra = 87.8), demonstrating that the as-prepared La2CaHfO6:Mn4+ phosphors can be used as red-emitting candidate in pc-WLEDs lighting.

A series of cyan-to-green emission tunable Ce3+-activated Ca1−xSrxSc2O4 phosphor compounds were developed through a high-temperature solid-state reaction. The crystal structures were analyzed by XRD and the Rietveld refinement, which confirm the phase purity and clarify the structural variation. The photoluminescence properties and thermal stabilities of the studied phosphors were investigated in detail. The diffuse reflectance spectra revealed the optical band gap to be 4.60 eV and 4.45 eV for CaSc2O4 and SrSc2O4 host, respectively. Due to the suitable optical bandgap, the Ce3+ ions could realize a highly efficient emission in the Ca1−xSrxSc2O4 matrix. The as-prepared phosphors show highly efficient emissions in the green to cyan regions of visible light. All developed compounds demonstrate asymmetric broad-bands with shoulders on the lower-energy sides. Cation substitution-dependent color-tunable evolution as a function of Sr2+ content in Ce3+-doped Ca1−xSrxSc2O4 was observed and investigated in detail. The regular blue-shift emission located in the cyan region with increasing Sr2+ content was attributed to the combined effect of the crystal field splitting and site-preferential occupation. The corresponding luminescence mechanism was analyzed through luminescence life decay measurements. Moreover, the increase of Sr2+ content could efficiently enhance the emission intensity and decrease thermal quenching, which should be ascribed to the lattice modification. The bright cyan and green emission band in the developed compounds, due to transitions in the 5d–4f levels of Ce3+, was found to be ideal for application in solid-state lighting devices. The feasibility of the compound as a potential white LED phosphor was demonstrated by fabricating a white LED with excellent emission properties.

The Xinbaishiyan tunnel in the reconstruction Chengdu-Kunming railway Ermeishan-Mipan section mainly runs through dolomite with dolomitic limestone, with an excavation area of 260 m2, a maximum span of 22.3 m, a maximum height of 14.4 m, a vector height of 7 m, and a rise-span ratio of 0.31. The tunnel has an extra-large cross-section and it is a low flat-ration railway tunnel. This paper mainly describes the the finite element analysis for this tunnel excavation that was used to guide the construction. Finite element software was used to model the tunnel according to the engineering geological conditions of the tunnel. These engineering geological conditions included the rock mass, system bolts, middle pipe shed, steel arch and shotcrete, grouting layer, second lining and so on. Nonlinear construction phase analysis was adopted. The results showed that the maximum vertical deformation of the tunnel vault and the middle of the invert was about 34 mm. The vertical deformation of the tunnel could be divided into an acceleration deformation section, linear deformation section, deceleration deformation section, and stable deformation section. The maximum horizontal deformation in the middle of the side wall was about 12.3 mm. Under the effect of the initial support, the equivalent stress of the side wall gradually increased with the excavation of the steps and the increase of the support structure. The axial force of the bolt in the middle of the side wall was larger than that in other places and the axial force of the middle pipe shed went along with the excavation of the tunnel in waves. The steel arch and the shotcrete had the maximum effective stress at the arch shoulder, which played the role of the deformation and pressure for the surrounding rock. During the construction, the length and height of the three-step method had to be set reasonably. The middle pipe shed and the system bolt supported the rock mass together. In the construction of the extra-large cross section and the flat tunnel, there was no need to set up temporary support, which was convenient for mechanical excavation.

A novel La2Mg1.14Zr0.86O6:Bi3+ double perovskite phosphor with excitation-induced blue/green photoluminescence tuning is reported. By designing Bi3+→ Eu3+ energy transfer, single-composition white light with wide-scale adjustable corrected color temperatures (CCTs) is successfully achieved. This work initiates a new insight to explore phosphors with excitation-induced photoluminescence tuning and wide CCT control for future intelligent LED lighting.

This paper aims to investigate the influence of active cooling and natural cooling on the electrical performance of photovoltaic (PV) modules in a cold highland area in winter, and the thermal performance of two photovoltaic thermal (PV/T) systems for space heating. A comparative system with exactly the same size of a PV system, liquid-cooled PV/T system, and heat pipe PV/T system was designed and constructed in Ganzi city, China. The energy performance of these systems was tested under real weather conditions for several days. The experimental results show that the PV module can achieve the cooling effect by natural cooling, with a daily average temperature between 30 °C and 40 °C, and an electrical efficiency 3.71% higher than that of active cooling. However, the temperature of naturally cooled PV modules fluctuates drastically with time, and the temperature changes above 10 °C in a short time. The solar energy conversion efficiency of PV/T systems is more than 2.67 times that of a PV system. The heating power of the liquid-cooled PV/T system and heat pipe PV/T system can reach 847.4 and 948.5 W, and the primary-energy saving efficiency can reach 68.8% and 76.7%. A comparison of the intercept efficiency shows that the heat pipe PV/T system has the best energy performance.

In order to study the influence of different spacing and angles of the axes of the two tunnels on the deformation and operation safety of existing tunnel in near-tunnel construction, the project in Fuzhou is taken to analysis. We use the finite element analysis software to construct a three-dimensional finite element model and carry on the numerical simulation, obtaining vertical vault displacement curves under different spacing and angles of the axes of the two tunnels. Then, we compare it with the actual monitoring data and do further analysis, we get following conclusions: (1) the main performance of the existing tunnel deformation is upward, the deformation decreases with the increase of the spacing and crossing angle, and the effect of the spacing on the existing tunnel vault deformation is far greater than the crossing angle. (2) When the spacing is less than 1.5 times of the new tunnel hole diameter, the maximum tunnel vault deformation occurs in the tunnel cross surface; when the spacing is greater than 1.5 times of the new tunnel hole diameter, the maximum tunnel vault deformation gradually moves toward to the center of the existing tunnel. The research results can provide some references for the design and construction of similar projects.

Considering that air source heat pumps have the advantages of fast heat supply response, high heat supply efficiency and environmental protection, air source heat pumps can quickly follow the change of wind power when wind power changes rapidly, and timely eliminate wind power. Air source heat pumps are considered in the day-ahead dispatch model of integrated electricity-heating system in this paper. The model regards generation cost for traditional units and combined heating power (CHP) units, operation cost for air source heat pumps and electric boilers and curtailment cost of wind power as its optimization target. The response speed of air source heat pumps and electric boilers are first considered in the constraint conditions. The wind power can be converted into heat energy by air source heat pumps so that improve the consumption of wind power when the wind curtailment is serious. The heat generated is used to provide system heat. The excess of heat can be stored in the thermal storage energy devices, which released to provide system heat at low troughs. Finally, the comparison between the examples shows that air source heat pumps not only can quickly respond to the change of wind power, but also have low operation cost and reduce system power generation cost .

The response speeds of electric boilers (EB) and energy storage devices (ESD) are different. The frequency bands of wind power that followed by EB and ESD are also different. In order to match EB and ESD with wind power in different time scales, an improved Variational Mode Decomposition (IVMD) is proposed. The original fully adaptive decomposition method is improved to an adaptive decomposition method based on the specified center frequency. Then, a multi-time scale rolling dispatch model for integrated electricity-heating systems is established. The center frequencies are determined according to the long-term trend of wind power, the response speeds of ESD and EB. Wind power is decomposed in three layers by IVMD. The first layer matches the long-term trend of wind power, which formulates the plan of units and EB. The second layer, which is adapted to the response speed of energy-type energy storage device (ETESD), determines the plan of ETESD, output adjustments of units and EB. The third layer, which is compatible with power-type energy storage device (PTESD), formulates the plan of PTESD. Finally, the analysis in case study verifies that it can effectively reduce the amount of wind curtailment and load shedding by the use of IVMD.