A Physics-informed Deep-learning Intensity Prediction Scheme for Tropical Cyclones over the Western North Pacific

Accurate prediction of tropical cyclone(TC)intensity is challenging due to the complex physical processes involved.Here,we introduce a new TC intensity prediction scheme for the western North Pacific(WNP)based on a time-dependent theory of TC intensification,termed the energetically based dynamical system(EBDS)model,together with the use of a long short-term memory(LSTM)neural network.In time-dependent theory,TC intensity change is controlled by both the internal dynamics of the TC system and various environmental factors,expressed as environmental dynamical efficiency.The LSTM neural network is used to predict the environmental dynamical efficiency in the EBDS model trained using besttrack TC data and global reanalysis data during 1982–2017.The transfer learning and ensemble methods are used to retrain the scheme using the environmental factors predicted by the Global Forecast System(GFS)of the National Centers for Environmental Prediction during 2017–21.The predicted environmental dynamical efficiency is finally iterated into the EBDS equations to predict TC intensity.The new scheme is evaluated for TC intensity prediction using both reanalysis data and the GFS prediction data.The intensity prediction by the new scheme shows better skill than the official prediction from the China Meteorological Administration(CMA)and those by other state-of-art statistical and dynamical forecast systems,except for the 72-h forecast.Particularly at the longer lead times of 96 h and 120 h,the new scheme has smaller forecast errors,with a more than 30%improvement over the official forecasts.

Review of Sc microalloying effects in Al-Cu alloys

Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a purpose.In this paper,recent advances in lengthscale-dependent scandium (Sc) microalloying effects in Al-Cu model alloys are reviewed.In coarse-grained Al-Cu alloys,the Sc-aided Cu/Sc/vacancies complexes that act as heterogeneous nuclei and Sc segregation at the θ′-Al_(2)Cu/matrix interface that reduces interfacial energy contribute significantly to θ′precipitation.By grain size refinement to the fine/ultrafine-grained scale,the strongly bonded Cu/Sc/vacancies complexes inhibit Cu and vacancy diffusing toward grain boundaries,promoting the desired intragranular θ′precipitation.At nanocrystalline scale,the applied high strain producing high-density vacancies results in the formation of a large quantity of (Cu Sc,vacancy)-rich atomic complexes with high thermal stability,outstandingly improving the strength/ductility synergy and preventing the intractable low-temperature precipitation.This review recommends the use of microalloying technology to modify the precipitation behaviors toward better combined mechanical properties and thermal stability in Al alloys.

On the Optimal Initial Inner-Core Size for Tropical Cyclone Intensification: An Idealized Numerical Study

Recent observational and numerical studies have revealed the dependence of the intensification rate on the inner-core size of tropical cyclones(TCs). In this study, with the initial inner-core size(i.e., the radius of maximum wind—RMW)varied from 20–180 km in idealized simulations using two different numerical models, we found a nonmonotonic dependence of the lifetime maximum intensification rate(LMIR) on the inner-core size. Namely, there is an optimal innercore size for the LMIR of a TC. Tangential wind budget analysis shows that, compared to large TCs, small TCs have large inward flux of absolute vorticity due to large absolute vorticity inside the RMW. However, small TCs also suffer from strong lateral diffusion across the eyewall, which partly offsets the positive contribution from large inward flux of absolute vorticity. These two competing processes ultimately lead to the TC with an intermediate initial inner-core size having the largest LMIR. Results from sensitivity experiments show that the optimal size varies in the range of 40–120 km and increases with higher sea surface temperature, lower latitude, larger horizontal mixing length, and weaker initial TC intensity. The 40–120 km RMW corresponds to the inner-core size most commonly found for intensifying TCs in observations, suggesting the natural selection of initial TC size for intensification. This study highlights the importance of accurate representation of TC inner-core size to TC intensity forecasts by numerical weather prediction models.

Research on the Influence of Raceway Waviness on the Vibration Characteristics of Deep Groove Ball Bearings

The dynamics model of a 2-degree-of-freedom deep groove ball bearing is established by incorporating the raceway surface waviness model comprising multiple sinusoidal functions superposition.The model is solved using the fourth-order Runge-Kutta method to obtain the vibration characteristics including displacement,velocity,acceleration,and frequency of the bearing.Validation of the model is accomplished through comparison with theoretical vibration frequencies.The influence of the amplitude of waviness of the inner and outer ring raceway surfaces of deep groove ball bearings on the vibration displacement,peak-to-peak vibration displacement and root-mean-square vibration acceleration is analyzed,and the results show that as the amplitude of the inner and outer ring raceway surfaces waviness increases,all the vibration characteristic indexes increase,indicating that the vibration amplitude of the bearings as well as the energy of the waviness-induced shock waveforms increase with the increase of the amplitude of the waviness.

基于核心素养的初中英语课堂教学变革

核心素养是基础教育课程改革深化的重要内容,是个体应对知识经济快速发展的必备品格和关键能力。基于初中英语核心素养的课程,必然要求有与之匹配的教学变革,以适应社会发展对人才的要求。在初中英语课堂教学中培育学生的核心素养,需要大力推进教学变革,即从知识本位教学走向素养本位教学,从课堂讲授走向合作探究,从教师独白教学情境走向师生、生生互动的复合式教学情境,从单一的教学评价走向综合型教学评价。

Improvements in Climate Simulation with Modifications to the Tiedtke Convective Parameterization in the Grid-Point Atmospheric Model of IAP LASG (GAMIL)

The grid-point atmospheric model of IAP LASG （GAMIL） was developed in and has been evaluated since early 2004. Although the model shows its ability in simulating the global climate, it suffers from some problems in simulating precipitation in the tropics. These biases seem to result mainly from the treatment of the subgrid scale convection, which is parameterized with Tiedtke＇s massflux scheme （or the Zhang-McFarlane scheme, as an option） in the model. In order to reduce the systematic biases, several modifications were made to the Tiedtke scheme used in GAMIL, including （1） an increase in lateral convective entrainment/detrainment rate for shallow convection, （2） inclusion of a relative humidity threshold for the triggering of deep convection, and （3） a reduced efficiency for the conversion of cloud water to rainwater in the convection scheme. Two experiments, one with the original Tiedtke scheme used in GAMIL and the other with the modified scheme, were conducted to evaluate the performance of the modified scheme in this study. The results show that both the climatological mean state, such as precipitation, temperature and specific humidity, and interannual variability in the model simulation are improved with the use of this modified scheme. Results from several additional experiments show that the improvements in the model performance in different regions mainly result from either the introduction of the relative humidity threshold for triggering of the deep convection or the suppressed shallow convection due to enhanced lateral convective entrainment/detrainment rates.

On Sea Surface Roughness Parameterization and Its Effect on Tropical Cyclone Structure and Intensity

A new parameterization scheme of sea surface momentum roughness length for all wind regimes, including high winds, under tropical cyclone （TC） conditions is constructed based on measurements from Global Positioning System （GPS） dropsonde. It reproduces the observed regime transition, namely, an increase of the drag coefficient with an increase in wind speed up to 40 m s-1 , followed by a decrease with a further increase in wind speed. The effect of this parameterization on the structure and intensity of TCs is evaluated using a newly developed numerical model, TCM4. The results show that the final intensity is increased by 10.5% （8.9%） in the maximum surface wind speed and by 8.1 hPa （5.9 hPa） in the minimum sea surface pressure drop with （without） dissipative heating. This intensity increase is found to be due mainly to the reduced frictional dissipation in the surface layer and little to do with either the surface enthalpy flux or latent heat release in the eyewall convection. The effect of the new parameterization on the storm structure is found to be insignificant and occurs only in the inner core region with the increase in tangential winds in the eyewall and the increase in temperature anomalies in the eye. This is because the difference in drag coefficient appears only in a small area under the eyewall. Implications of the results are briefly discussed.

Recent progress on the recycling technology of Li-ion batteries

Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles.With the booming of the respective markets,a huge quantity of spent LIBs that typically use either LiFePO_(4) or Li N_(x)Co_(y)Mn_(z)O_(2) cathode materials will be produced in the very near future,imposing significant pressure for the development of suitable disposal/recycling technologies,in terms of both environmental protection and resource reclaiming.In this review,we firstly do a comprehensive summary of the-state-of-art technologies to recycle Li N_(x)Co_(y)Mn_(z)O_(2) and LiFePO_(4)-based LIBs,in the aspects of pretreatment,hydrometallurgical recycling,and direct regeneration of the cathode materials.This closed-loop strategy for cycling cathode materials has been regarded as an ideal approach considering its economic benefit and environmental friendliness.Afterward,as for the exhausted anode materials,we focus on the utilization of exhausted anode materials to obtain other functional materials,such as graphene.Finally,the existing challenges in recycling the LiFePO_(4) and Li N_(x)Co_(y)Mn_(z)O_(2) cathodes and graphite anodes for industrial-scale application are discussed in detail;and the possible strategies for these issues are proposed.We expect this review can provide a roadmap towards better technologies for recycling LIBs,shed light on the future development of novel battery recycling technologies to promote the environmental benignity and economic viability of the battery industry and pave way for the large-scale application of LIBs in industrial fields in the near future.

Numerical Study of Boundary Layer Structure and Rainfall after Landfall of Typhoon Fitow(2013): Sensitivity to Planetary Boundary Layer Parameterization

The boundary layer structure and related heavy rainfall of Typhoon Fitow(2013), which made landfall in Zhejiang Province, China, are studied using the Advanced Research version of the Weather Research and Forecasting model, with a focus on the sensitivity of the simulation to the planetary boundary layer parameterization. Two groups of experiments—one with the same surface layer scheme and including the Yonsei University(YSU), Mellor–Yamada–Nakanishi–Niino Level 2.5,and Bougeault and Lacarrere schemes; and the other with different surface layer schemes and including the Mellor–Yamada–Janjic′ and Quasi-Normal Scale Elimination schemes—are investigated. For the convenience of comparative analysis, the simulation with the YSU scheme is chosen as the control run because this scheme successfully reproduces the track, intensity and rainfall as a whole. The maximum deviations in the peak tangential and peak radial winds may account for 11% and 33%of those produced in the control run, respectively. Further diagnosis indicates that the vertical diffusivity is much larger in the first group, resulting in weaker vertical shear of the tangential and radial winds in the boundary layer and a deeper inflow layer therein. The precipitation discrepancies are related to the simulated track deflection and the differences in the simulated low-level convergent flow among all tests. Furthermore, the first group more efficiently transfers moisture and energy and produces a stronger ascending motion than the second, contributing to a deeper moist layer, stronger convection and greater precipitation.

Recent Progress in Emerging Two‑Dimensional Transition Metal Carbides

As a new member in two-dimensional materials family,transition metal carbides(TMCs)have many excellent properties,such as chemical stability,in-plane anisotropy,high conductivity and flexibility,and remarkable energy conversation efficiency,which predispose them for promising applications as transparent electrode,flexible electronics,broadband photodetectors and battery electrodes.However,up to now,their device applications are in the early stage,especially because their controllable synthesis is still a great challenge.This review systematically summarized the state-of-the-art research in this rapidly developing field with particular focus on structure,property,synthesis and applicability of TMCs.Finally,the current challenges and future perspectives are outlined for the application of 2D TMCs.

Unprecedented Heatwave in Western North America during Late June of 2021: Roles of Atmospheric Circulation and Global Warming

An extraordinary and unprecedented heatwave swept across western North America(i.e.,the Pacific Northwest)in late June of 2021,resulting in hundreds of deaths,a massive die-off of sea creatures off the coast,and horrific wildfires.Here,we use observational data to find the atmospheric circulation variabilities of the North Pacific and Arctic-Pacific-Canada patterns that co-occurred with the development and mature phases of the heatwave,as well as the North America pattern,which coincided with the decaying and eastward movement of the heatwave.Climate models from the Coupled Model Intercomparison Project(Phase 6)are not designed to simulate a particular heatwave event like this one.Still,models show that greenhouse gases are the main reason for the long-term increase of average daily maximum temperature in western North America in the past and future.

Facing challenges with hope:universal immune cells for hematologic malignancies

Many patients have achieved a favorable overall survival rate since allogenic hematopoietic stem cell transplantation(allo-HSCT)has been widely implemented to treat hematologic malignancies.However,graft-versus-host disease(GVHD)and complications of immunosuppressive drugs after allo-HSCT are the main causes of non-relapse mortality and a poor quality of life.In addition,GVHD and infusion-induced toxicity still occur with donor lymphocyte infusions(DLIs)and chimeric antigen receptor(CAR)T-cell therapy.Because of the special immune tolerance characteristics and anti-tumor ability of universal immune cells,universal immune cell therapy may strongly reduce GVHD,while simultaneously reducing tumor burden.Nevertheless,widespread application of universal immune cell therapy is mainly restricted by poor expansion and persistence efficacy.Many strategies have been applied to improve universal immune cell proliferation and persistence efficacy,including the use of universal cell lines,signaling regulation and CAR technology.In this review we have summarized current advances in universal immune cell therapy for hematologic malignancies with a discussion of future perspectives.

In vivo tumor detection with com bined MR-Photoacoustic-Thermoacoustic imaging

Here,we report a new method using combined magnetic resonance(MR)-Photoacoustic(PA)-Thermoacoustic(TA)imaging techmiques,and demonstrate its unique ability for in vrivo cancer detection using tumor-bearing mice.Circular scanning TA and PA imaging systems were used to recover the dielectric and optical property dist ributions of three colon carcinoma bearing mice While a 7.0-T magnetic resonance imaging(MRI)unit with a mouse body volume coil was utilized for high resolution structural imaging of the same mice.Three plastic tubes flled with soybean sauce were used as fiducial markers for the co-registration of MR,PA and TA images.The resulting fused images provided both enhanced tumor margin and contrast relative to the surrounding normal tissues.In particular,some finger-like protrusions extending into the surrounding tissues were revealed in the MR/TA infused images.These results show that the tissue functional optical and dielectric properties provided by PA and TA images along with the anatomical structure by MRI in one picture make accurate tumor identification easier.This combined MR-PA-TA-imaging strategy has the potential to offer a dinically useful triple-modality tool for accurate cancer detection and for intraoper ative surgical navigation.

Drop casting based superhydrophobic and electrically conductive coating for high performance strain sensing

Conductive polymer composites(CPCs)strain sensors exhibit promising applications in flexible electronics,people’s health monitoring,etc.It remains a big challenge to develop a simple and cost-effective method to prepare CPCs with high conductivity,corrosion resistance,strong interfacial adhesion and high sensitivity.Here,we propose a facile“drop-casting and fluorination”strategy to fabricate superhydrophobic and highly electrically conductive coating by Ag precursor adsorption onto a commercially available elastic tape,subsequent chemical reduction and final fluorination.The Ag nanoparticles could not only construct the electrically conductive network but also greatly enhance the surface roughness.The contact angle and electrical conductivity of the coating can reach as high as 156°and 126 S/cm,respectively.When used for strain sensing,the superhydrophobic and conductive coating shows a high gauger factor(up to 7631 with the strain from 44%to 50%)and outstanding recyclability.The strain sensor could monitor different body joint motions with the stable and reliable sensing signals even after long time treatment in a corrosive solution.

Involucre fossils of Carpinus,a northern temperate element,from the Miocene of China and the evolution of its species diversity in East Asia

East Asia has long been recognized as a major center for temperate woody plants diversity.Although several theories have been proposed to explain how the diversity of these temperate elements accumulated in the region,the specific process remains unclear.Here we describe six species of Carpinus,a typical northern hemisphere temperate woody plant,from the early Miocene of the Maguan Basin,southwestern China,southern East Asia.This constitutes the southernmost,and the earliest occurrence that shows a high species diversity of the genus.Together with other Carpinus fossil records from East Asia,we show that the genus had achieved a high diversity in East Asia at least by the middle Miocene.Of the six species here described,three have become extinct,indicating that the genus has experienced apparent species loss during its evolutionary history in East Asia.In contrast,the remaining three species closely resemble extant species,raising the possibility that these species may have persisted in East Asia at least since the early Miocene.These findings indicate that the accumulation of species diversity of Carpinus in East Asia is a complex process involving extinction,persistence,and possible subsequent speciation.

Impact of the Western Pacific Tropical Easterly Jet on Tropical Cyclone Genesis Frequency over the Western North Pacific

Although it is well known that the tropical easterly jet(TEJ)has a significant impact on summer weather and climate over India and Africa,whether the TEJ exerts an important impact on tropical cyclone(TC)activity over the western North Pacific(WNP)remains unknown.In this study,we examined the impact of the TEJ on the interannual variability of TC genesis frequency over the WNP in the TC season(June-September)during 1980-2020.The results show a significant positive correlation between TC genesis frequency over the WNP and the jet intensity in the entrance region of the TEJ over the tropical western Pacific(in brief WP_TEJ),with a correlation coefficient as high as 0.66.The intensified WP_TEJ results in strong ageostrophic northerly winds in the entrance region and thus upper-level divergence to the north of the jet axis over the main TC genesis region in the WNP.This would lead to an increase in upward motion in the troposphere with enhanced low-level convergence,which are the most important factors to the increases in low-level vorticity,mid-level humidity and low-level eddy kinetic energy,and the decreases in sea level pressure and vertical wind shear in the region.All these changes are favorable for TC genesis over the WNP and vice versa.Further analyses indicate that the interannual variability of the WP_TEJ intensity is likely to be linked to the local diabatic heating over the Indian Ocean-western Pacific and the central Pacific El Ni?o-Southern Oscillation.

Laser direct writing derived robust carbon nitride films with efficient photon-to-electron conversion for multifunctional photoelectrical applications

Carbon nitride,an emerging polymeric semiconductor,has attracted attention in research ranging from photocatalysis to photodetection due to its favorable visible light response and high physicochemical stability.For its practical device application,the fabrication of high-quality carbon nitride films on substrates is essential.However,conventional methodologies to achieve high polymerization of carbon nitride are often accompanied by its decomposition,significantly compromising the film quality.Herein,we report an ultrafast fabrication of carbon nitride film by laser direct writing(LDW).The instantaneous high temperature and pressure during LDW can efficiently boost the polymerization of carbon nitride and suppress its decomposition,resulting in high-quality carbon nitride film with excellent mechanical stability with the substrate.Due to the efficient photon-to-electron conversion,it exhibits an outstanding photoelectrochemical water splitting and optoelectronic detection capability,even under strong acid/alkaline conditions.This study thus offers a facile and efficient LDW strategy for the rapid fabrication of carbon nitride film photoelectrodes,demonstrating its great feasibility in multifunctional photoelectrical applications,including but not limited to photoelectrochemical water splitting and optoelectronic detection.

Typhoon Track,Intensity,and Structure:From Theory to Prediction

To improve understanding of essential aspects that influence forecasting of tropical cyclones(TCs),the National Key Research and Development Program,Ministry of Science and Technology of the People's Republic of China conducted a five-year project titled“Key Dynamic and Thermodynamic Processes and Prediction for the Evolution of Typhoon Intensity and Structure”(KPPT).Through this project,new understandings of TC intensification,including outer rainbanddriven secondary eyewall formation and the roles of boundary layer dynamics and vertical wind shear,and improvements to TC data assimilation with integrated algorithms and adaptive localizations are achieved.To promote a breakthrough in TC intensity and structure forecasting,a new paradigm for TC evolution dynamics(i.e.,the correlations,interactions,and error propagation among the triangle of TC track,intensity,and structure)is proposed;and an era of dynamic-constrained,big-data driven,and strongly coupled data assimilation at the subkilometer scale and seamless prediction is expected.

Microphysical Properties of Rainwater in Typhoon Usagi(2013):A Numerical Modeling Study

A 2-km resolution simulation using the Weather Research and Forecasting model with Morrison microphysics was employed to investigate the rainwater microphysical properties during different stages of Typhoon Usagi(2013) in the inner-core and outer region. The model reproduced the track, intensity, and overall structure of Usagi(2013) reasonably. The simulated raindrop size distribution showed a rapid increase in small-size raindrop concentration but an oscillated decrease in large-size ones in the inner-core region, corresponding well with the upward motion. It was found that there existed two levels(1.25 and 5.25 km) of maximum number concentration of raindrops. The ice-related microphysics at high levels was stronger than the warm-rain processes at low levels. The larger raindrops formed by self-collection in the inner-core suffered from significant breakup, but the raindrops outside the eyewall did not experience evident breakup. Model results indicated that the dominant terms in the water vapor budget were the horizontal moisture flux convergence(HFC) and local condensation and deposition. The evaporation from the ocean surface(PBL) was ~10% of the HFC in the inner core, but up to 40% in the outer region as the air therein was far from saturation. Furthermore, water vapor in the outer region was obtained equally through evaporation from the cloud and inward transportation from the environment. An earlier start of cloud microphysical processes in the inner-core region was evident during the intensification stage, and the continuous decreasing of condensation in both the inner-core and outer regions might imply the beginning of the storm weakening.

A High-resolution Simulation of Supertyphoon Rammasun(2014)--Part Ⅰ:Model Verification and Surface Energetics Analysis

A 72-h high-resolution simulation of Supertyphoon Rammasun （2014） is performed using the Advanced Research Weather Research and Forecasting model. The model covers an initial 18-h spin-up, the 36-h rapid intensification （RI） period in the northern South China Sea, and the 18-h period of weakening after landfall. The results show that the model reproduces the track, intensity, structure of the storm, and environmental circulations reasonably well. Analysis of the surface energetics under the storm indicates that the storm＇s intensification is closely related to the net energy gain rate （eg）, defined as the difference between the energy production （PD） due to surface entropy flux and the energy dissipation （Ds） due to surface friction near the radius of maximum wind （RMW）. Before and during the RI stage, the ~：g is high, indicating sufficient energy supply for the storm to intensify. However, the Sg decreases rapidly as the storm quickly intensifies, because the Ds increases more rapidly than the PD near the RMW. By the time the storm reaches its peak intensity, the Ds is about 20% larger than the PD near the RMW, leading to a local energetics deficit under the eyewall. During the mature stage, the PD and Ds can reach a balance within a radius of 86 km from the storm center （about 2.3 times the RMW）. This implies that the local PD under the eyewall is not large enough to balance the Ds, and the radially inward energy transport from outside the eyewall must play an important role in maintaining the storm＇s intensity, as well as its intensification.