New Approach to Lightning Strike Risk Assessment of Wind Farm

In the past,lightning strike risk assessment of buildings mainly referred to the Protection against Lightning—Part 2:Risk Management(IEC 62305-2-2010)based on protection angle method.Lightning strike risk assessment of wind farms was conducted according to the Lightning Protection for Wind Energy System(IEC 61400-24-2019),which proposed the method of lightning strike risk assessment for wind turbine.In fact,the basic idea of the two is the same,that is,the source of the lightning strike wind turbine is transformed from the former S1-S4 to the latter N D-N DJ.According to the above method,wind farm was evaluated,and it has been proved that the practice can not achieve good results.After 2018,China has issued the Guide to Evaluation of Lightning Protection Technology in Buildings(T/GZLY 3-2022)and the Technical Specifications for Lightning Interception in Forest Areas(T/LYCY 4062-2024)based on semicircle protection,in which the source of risk defined by lightning point was closer to the reality,highly targeted and effective.Taking offshore wind farm as an example,this paper introduced a new method of establishing six evaluation indicators to determine the risk level according to the principle of compliance and the new protection technology of semi-circular method,which can be used as a reference for technical personnel.

25%-Efficiency flexible perovskite solar cells via controllable growth of SnO_(2)

High power conversion efficiency(PCE)flexible perovskite solar cells(FPSCs)are highly desired power sources for aerospace crafts and flexible electronics.However,their PCEs still lag far behind their rigid counterparts.Herein,we report a high PCE FPSC by controllable growth of a SnO_(2)electron transport layer through constant pH chemical bath deposition(CBD).The application of SnSO_(4)as tin source enables us to perform CBD without strong acid,which in turn makes it applicable to acid-sensitive flexible indium tin oxide.Furthermore,a mild and controllable growth environment leads to uniform particle growth and dense SnO_(2)deposition with full coverage and reproducibility,resulting in a record PCE of up to 25.09%(certified 24.90%)for FPSCs to date.The as-fabricated FPSCs exhibited high durability,maintaining over 90% of their initial PCE after 10000 bending cycles.

Quantifying the effects of short-term heat stress at booting stage on nonstructural carbohydrates remobilization in rice

Extreme heat stress events are becoming more frequent under anticipated climate change,which can have devastating impacts on rice growth and yield.To quantify the effects of short-term heat stress at booting stage on nonstructural carbohydrates(NSC)remobilization in rice,two varieties(Nanjing 41 and Wuyunjing 24)were subjected to 32/22/27°C(maximum/minimum/mean),36/26/31°C,40/30/35°C,and 44/34/39°C for 2,4 and 6 days in phytotrons at booting stage during 2014 and 2015.Yield and yield components,dry matter partitioning index(DMPI),NSC accumulation and translocation were measured and calculated.The results showed that the increase of high-temperature level and duration significantly reduced grain yield by suppressing spikelet number per panicle,seed-setting rate,and grain weight.Heat stress at booting decreased DMPI in panicles,increased DMPI in stems,but had no significant effect on photosynthetic rate.Stem NSC concentration increased whereas panicles NSC concentration,stem NSC translocation efficiency,and contribution of stem NSC to grain yield decreased.Severe heat stress even transformed the stem into a carbohydrate sink during grain filling.The heat-tolerant Wuyunjing 24 showed a higher NSC transport capacity under heat stress than the heat-sensitive Nanjing 41.Heat degree-days(HDD),which combines the effects of the intensity and duration of heat stress,used for quantifying the impacts of heat stress indicates the threshold HDD for the termination of NSC translocation is 9.82°C day.Grain yield was negatively correlated with stem NSC concentration and accumulation at maturity,and yield reduction was tightly related to NSC translocation reduction.The results suggest that heat stress at booting inhibits NSC translocation due to sink size reduction.Therefore,genotypes with higher NSC transport capacity under heat stress could be beneficial for rice yield formation.

Experimental Research on the Dynamic Lubricating Performance of Slipper/Swash Plate Interface in Axial Piston Pumps

The interface between the slipper/swash plate is one of the most important frication pairs in axial piston pumps.The test of this interface in a real pump is very challenging.In this paper,a novel pump prototype is designed and a test rig is set up to study the dynamic lubricating performance of the slipper/swash-plate interface in axial piston machines.Such an experimental setup can simulate the operating condition of a real axial piston pump without changing the relative motion relationship of the interfaces.Considering the lubricant oil film thickness as the main measurement parameter,the attitude of the slipper under the conditions of different load pressure,rotation speed and charge pressure are studied experimentally.After the test,the wear state of the swash plate is observed.According to the friction trace on the surface of the swash plate,the prediction for the attitude of the slipper and the zone easy to wear are verified.

Experimental Study of Churning Losses in Swash Plate Axial Piston Pump

The problem of the churning loss in swash plate axial piston machines is investigated through experimental measurement and theoretical analysis. Several works surrounding churning loss in hydraulic components have been proposed in the past, but few have conducted experimental studies and accounted for both dry and wet housing conditions. In this study,a specialized experimental setup is established, which includes a transparent test pump diligently designed for performing various functions of tests. The test pump can work as a real pump without losing any actual features of pump operation. The torque loss in both the dry housing pump and wet housing pump is measured in terms of the shaft speed and its predictive model is also developed analytically. The comparisons between measured and calculated torque loss are presented, showing how speed influences torque loss in both conditions. The advantage/disadvantages of the two cases are summarized. The significance of the test setup is highlighted by verifying the proposed model, which can advance the understanding of energy losses of high speed pumps in future.

Double Layer Composite Electrode Strategy for Efficient Perovskite Solar Cells with Excellent Reverse-Bias Stability

Perovskite solar cells(PSCs)have become the represent-atives of next generation of photovoltaics;nevertheless,their stability is insufficient for large scale deployment,particularly the reverse bias stability.Here,we propose a transparent conducting oxide(TCO)and low-cost metal composite electrode to improve the stability of PSCs without sacrificing the efficiency.The TCO can block ion migrations and chemical reactions between the metal and perovskite,while the metal greatly enhances the conductivity of the composite electrode.As a result,composite electrode-PSCs achieved a power conversion efficiency(PCE)of 23.7%(certified 23.2%)and exhibited excellent stability,maintaining 95%of the initial PCE when applying a reverse bias of 4.0 V for 60 s and over 92%of the initial PCE after 1000 h continuous light soaking.This composite electrode strategy can be extended to different combinations of TCOs and metals.It opens a new avenue for improving the stability of PSCs.

Dynamic Characteristics of Lubrication and Wear Prediction of Slipper/Swash-Plate in Axial Piston Pumps

A novel dynamic model describing the slipper posture of the swash plate in axial piston pumps is proposed, taking into account the hydrodynamic and squeezing effects, which involves three degrees of freedom. The variation in the lubricating film thickness and the slipper tilt are accurately calculated. The influence of hydrodynamic effects and charging pressure on the slipper lubrication is discussed. The minimum film thickness, the overturning angle and the azimuth angle are obtained.Then, the trajectory of minimum thickness on the friction surface of the swash plate is predicted, the accuracy of which can be verified with the abrasion distribution of an actual swash plate. Research results can predict the durability and provide theoretical help for the design of the slipper.

Information freshness optimization of multiple status update streams in Internet of things:Generation rate control and service rate reservation

The Internet of things(IoT)has become a key infrastructure providing up-to-date and fresh information for policy analysis and decision-making of upper-layer applications.However,there are limited sensing and communication resources in IoT devices,which significantly affects the timeliness and freshness of the updated status.This work proposes two schemes,namely,the generation rate control and service rate reservation schemes,to improve the overall information freshness of multiple status update streams at the receiver.Specifically,using the recently proposed Age of Information(AoI)as the metric for evaluating information freshness,we characterized the overall information freshness,i.e.,the overall average AoI at the receiver for both schemes,by considering the urgency difference of status update and streams.Both schemes for status updates and streams,respectively,were formulated as two optimization problems.We proved that both problems are convex and the optimal generation and service rates for different streams are found by the standard convex optimization algorithm.Moreover,we proposed both approximate optimal generation and approximate optimal service rate for fast deployment in heavy and light load cases.Numerical results verify the theoretical findings and accuracy of the proposed approximate solutions,guiding the design and deployment of IoT.

Brominated PEAI as Multi-Functional Passivator for High-Efficiency Perovskite Solar Cell

The interfaces of perovskite solar cells(PSCs)are well known to be rich in deep-level carrier traps,which serve as non-radiative recombination centers and limit the open-circuit voltage(Voc)and power conversion efficiency(PCE)of PSCs.Defect chemistry and surface passivators have been researched extensively and mainly focused on the neutralization of uncoordinated lead or anion defects.Herein,a novel brominated passivator 2-bromophenethylammonium iodide(2-Br-PEAI)is introduced for a multi-functional passivation effect at the perovskite interface.The brominated species readily form 2D perovskite on top of the 3D perovskite and multi-interact with the 3D perovskite surface.Apart from the halide vacancy filling and anion bonding ability,the Br atoms on the benzene ring can interact with the FA cations via strong hydrogen bonding N-H…Br and interact with the[PbI_(6)]^(4−)inorganic framework.The interface defects in the PSCs are well passivated,minimizing non-radiative recombination and enhancing device performance.As a result,a champion PCE of 24.22%was achieved with high V_(oc)and fill factor.In addition,modified devices also showed enhanced operational stability(retention of>95%initial PCE after 400 h)and humidity resistance(>90%initial PCE maintained after 1500 h under~50%RH).

Using Recurrent Neural Network Structure and Multi-Head Attention with Convolution for Fraudulent Phone Text Recognition

Fraud cases have been a risk in society and people’s property security has been greatly threatened.In recent studies,many promising algorithms have been developed for social media offensive text recognition as well as sentiment analysis.These algorithms are also suitable for fraudulent phone text recognition.Compared to these tasks,the semantics of fraudulent words are more complex and more difficult to distinguish.Recurrent Neural Networks(RNN),the variants ofRNN,ConvolutionalNeuralNetworks(CNN),and hybrid neural networks to extract text features are used by most text classification research.However,a single network or a simple network combination cannot obtain rich characteristic knowledge of fraudulent phone texts relatively.Therefore,a new model is proposed in this paper.In the fraudulent phone text,the knowledge that can be learned by the model includes the sequence structure of sentences,the correlation between words,the correlation of contextual semantics,the feature of keywords in sentences,etc.The new model combines a bidirectional Long-Short Term Memory Neural Network(BiLSTM)or a bidirectional Gate Recurrent United(BiGRU)and a Multi-Head attention mechanism module with convolution.A normalization layer is added after the output of the final hidden layer.BiLSTM or BiGRU is used to build the encoding and decoding layer.Multi-head attention mechanism module with convolution(MHAC)enhances the ability of the model to learn global interaction information and multi-granularity local interaction information in fraudulent sentences.A fraudulent phone text dataset is produced by us in this paper.The THUCNews data sets and fraudulent phone text data sets are used in experiments.Experiment results show that compared with the baseline model,the proposed model(LMHACL)has the best experiment results in terms of Accuracy,Precision,Recall,and F1 score on the two data sets.And the performance indexes on fraudulent phone text data sets are all above 0.94.

Simultaneous Structure-Coupled Joint Inversion of Gravity and Magnetic Data Based on a Damped Least-Squares Technique

The structure-coupled joint inversion method of gravity and magnetic data is a powerful tool for?developing improved physical property models with high resolution and compatible features;?however, the conventional procedure is inefficient due to the truncated singular values decomposition?(SVD) process at each iteration. To improve the algorithm, a technique using damped leastsquares?is adopted to calculate the structural term of model updates, instead of the truncated SVD. This?produces structural coupled density and magnetization images with high efficiency. A so-called?coupling factor is introduced to regulate the tuning of the desired final structural similarity level.?Synthetic examples show that the joint inversion results are internally consistent and achieve?higher?resolution than separated. The acceptable runtime performance of the damped least squares?technique used in joint inversion indicates that it is more suitable for practical use than the truncated SVD method.

Lithological Characterization and Its Application Based on Three-Dimensional Structure-Coupled Joint Inversion of Gravity and Magnetic Data

Incorporating structural-coupling constraint, known as the cross-gradients criterion, helps to improve the focussing trend in cross-plot of multiple physical properties. Based on this feature, a?post-processing technique is studied to characterize the lithological types of subsurface geological materials after joint inversion. A simple domain transform, which converts two kinds of participant physical properties into an artificial complex array, is adopted to extract anomalies manually from homogenous host rock. A synthetic example shows that structure-coupled joint inverted results tend to concentrate on the feature trends in the cross-plot, and the main geological targets are recovered well by a radius-azimuth plot. In a field data example, the lithological characterization?reveals that the main rock types interpreted in the study area agree with the geological information, thus demonstrating the feasibility of this technique.

A MATLAB-Based Numerical and GUI Implementation of Cross-Gradients Joint Inversion of Gravity and Magnetic Data

The cross-gradients joint inversion technique has been applied to multiple geophysical data with a significant improvement on compatibility, but its numerical implementation for practical use is rarely discussed in the literature. We present a MATLAB-based three-dimensional cross-gradients joint inversion program with application to gravity and magnetic data. The input and output information was examined with care to create a rational, independent design of a graphical user interface (GUI) and computing kernel. For 3D visualization and data file operations, UBC-GIF tools are invoked using a series of I/O functions. Some key issues regarding the iterative joint inversion algorithm are also discussed: for instance, the forward difference of cross gradients, and matrix pseudo inverse computation. A synthetic example is employed to illustrate the whole process. Joint and separate inversions can be performed flexibly by switching the inversion mode. The resulting density model and susceptibility model demonstrate the correctness of the proposed program.

Research on Fault Prediction of Modern Aviation Electronic Equipment Based on Improved Grey Model

The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain the best forecast dimension and using metabolism to make the model parameters adaptively change. Finally, the improved Grey Model is used to predict the fault of high voltage power supply circuit of a certain type of modern air-borne radar. The results which are computed and simulated by Matlab software show that the forecast precision of improved Grey Model is higher than that of original Grey Model.

Examining urban-rural differences in the impact of Internet use on older adults’ depression: evidence from China

Both Internet use’s impact on depression and urban-rural disparities related to information and communication technologies(ICTs)are crucial topics in the information systems discipline.So far,limited studies have explored these topics in a comprehensive way.This study aims to explore the impact of Internet use on urban and rural older adults’depression and provide insights into how ICTs play positive roles in human behaviors.Based on data from the China Health and Retirement Longitudinal Study,we used the panel-data regression approach to examine the relationships between older adults’Internet use and depression,and adopted the propensity score matching and the difference-in-difference approach to test the robustness of our findings.We found that the influencing mechanisms behind Internet use’s impact on urban and rural older adults’depression are different.Internet use not only directly reduces rural older adults’depression but also indirectly reduces it via the mediation of social activity,while the impact of Internet use on urban older adults’depression is fully mediated by social activity.We found that Internet use exerts different impacts on urban and rural older adults’depression,and rural older adults can receive a greater benefit.

Model moisture transport in oil-paper insulation of transformer:Theory and experiment

The insulation performance of oil paper insulation is significantly affected by moisture such that monitoring moisture content is important.However,it is difficult to obtain the moisture content accurately due to its dynamic change under multi physical fields.Studying the moisture transportation in oil paper insulation under multi physical fields becomes a vital method in solving the problem.A multi physical model describing moisture migration was proposed,which considered the effects of temperature on moisture in different existing states in oil-immersed paper(OIP).The temperature distribution formed a vapour pressure gradient to drive moisture migration and affected migration speed.Then,experiments and simulations of moisture migration were performed,which showed that the experiments were in good agreement with simulation.The results revealed that the temperature gradient caused uneven moisture distribution and the increased temperature reduced OIP moisture content.The established model could fully characterise moisture migration under temperature gradient,which provided a theoretical reference for predicting the risk of partial dampness and evaluating insulation performance.

国产生物补片与聚丙烯补片在日间腹股沟斜疝Lichtenstein修补术中的疗效对比

目的探讨猪小肠黏膜下层生物补片在腹股沟疝日间手术中的应用价值。方法回顾分析2019年1月至2020年12月武汉大学中南医院疝病诊疗中心100例接受日间Lichtenstein手术的腹股沟疝患者。根据使用补片的不同分为试验组(SIS补片)和对照组(聚丙烯补片),记录2组患者的临床参数和术后并发症发生情况,对比数据进行统计学分析。结果2组手术时间,差异无统计学意义(P>0.05)。术后1周,试验组患者术后发热、切口血清肿多于对照组(P<0.05);而试验组术后切口感染和疼痛发生率均低于对照组(P<0.05)。术后1年,试验组慢性疼痛、异物感发生率均低于对照组(P<0.05);2组复发率比较,差异无统计学意义(P>0.05)。结论在开放腹股沟疝手术中,SIS补片术后早期发热及血清肿发生率高于聚丙烯补片,但在早期切口感染及疼痛方面优于聚丙烯补片;在远期慢性疼痛和异物感方面,SIS补片也优于聚丙烯补片,临床应用应遵循个体化原则。

Identification and analysis of intermediate-size noncoding RNAs in the rhesus macaque fetal brain

Although only about 2%of the human genome has proved to be protein-coding genes,recent advances in genome wide analysis have revealed that the majority of the genome is transcribed,mainly from noncoding segments that were once considered＂junk sequences＂or＂dark matters＂（Liu et al.,2011a;Zhang et al.,2014b）. In addition to the well-characterized housekeeping non- coding RNAs （ncRNAs） （tRNA, rRNA, small nuclear RNA and small nucleolar RNAs） and some small regulatory ncRNAs （microRNAs and small interfering RNAs）, the transcriptome of mammals could also pervasively have been transcribed long noncoding RNAs （lncRNAs, at least 200 nt） （Rinn and Chang, 2012; Xie et al., 2012）.

Stratified-structural hydrogel incorporated with magnesium-ion-modified black phosphorus nanosheets for promoting neuro-vascularized bone regeneration

Angiogenesis and neurogenesis play irreplaceable roles in bone repair.Although biomaterial implantation that mimics native skeletal tissue is extensively studied,the nerve-vascular network reconstruction is neglected in the design of biomaterials.Our goal here is to establish a periosteum-simulating bilayer hydrogel and explore the efficiency of bone repair via enhancement of angiogenesis and neurogenesis.In this contribution,we designed a bilayer hydrogel platform incorporated with magnesium-ion-modified black phosphorus(BP)nanosheets for promoting neuro-vascularized bone regeneration.Specifically,we incorporated magnesium-ion-modified black phosphorus(BP@Mg)nanosheets into gelatin methacryloyl(GelMA)hydrogel to prepare the upper hydrogel,whereas the bottom hydrogel was designed as a double-network hydrogel system,consisting of two interpenetrating polymer networks composed of GelMA,PEGDA,andβ-TCP nanocrystals.The magnesium ion modification process was developed to enhance BP nanosheet stability and provide a sustained release platform for bioactive ions.Our results demonstrated that the upper layer of hydrogel provided a bionic periosteal structure,which significantly facilitated angiogenesis via induction of endothelial cell migration and presented multiple advantages for the upregulation of nerve-related protein expression in neural stem cells(NSCs).Moreover,the bottom layer of the hydrogel significantly promoted bone marrow mesenchymal stem cells(BMSCs)activity and osteogenic differentiation.We next employed the bilayer hydrogel structure to correct rat skull defects.Based on our radiological and histological examinations,the bilayer hydrogel scaffolds markedly enhanced early vascularization and neurogenesis,which prompted eventual bone regeneration and remodeling.Our current strategy paves way for designing nerve-vascular network biomaterials for bone regeneration.

Rice metabolic regulatory network spanning the entire life cycle

As one of the most important crops in the world,rice(Oryza sativa)is a model plant for metabolome research.Although many studies have focused on the analysis of specific tissues,the changes in metab-olite abundance across the entire life cycle have not yet been determined.In this study,combining both tar-geted and nontargeted metabolite profiling methods,a total of 825 annotated metabolites were quantified in rice samples from different tissues covering the entire life cycle.The contents of metabolites in different tissues of rice were significantly different,with various metabolites accumulating in the plumule and radicle during seed germination.Combining these data with transcriptome data obtained from the same time period,we constructed the Rice Metabolic Regulation Network.The metabolites and co-expressed genes were further divided into 12 clusters according to their accumulation patterns,with members within each cluster displaying a uniform and clear pattern of abundance across development.Using this dataset,we established a comprehensive metabolic profile of the rice life cycle and used two independent strategies to identify novel transcription factors-namely the use of known regulatory genes as bait to screen for new networks underlying lignin metabolism and the unbiased identification of new glycerophospholipid metabolism regulators on the basis of tissue specificity.This study thus demonstrates how guilt-by-association analysis of metabolome and transcriptome data spanning the entire life cycle in cereal crops provides novel resources and tools to aid in understanding the mechanisms underlying important agro-nomic traits.