Adaptive Recurrent Iterative Updating Stereo Matching Network

When training a stereo matching network with a single training dataset, the network may overly rely on the learned features of the single training dataset due to differences in the training dataset scenes, resulting in poor performance on all datasets. Therefore, feature consistency between matched pixels is a key factor in solving the network’s generalization ability. To address this issue, this paper proposed a more widely applicable stereo matching network that introduced whitening loss into the feature extraction module of stereo matching, and significantly improved the applicability of the network model by constraining the variation between salient feature pixels. In addition, this paper used a GRU iterative update module in the disparity update calculation stage, which expanded the model’s receptive field at multiple resolutions, allowing for precise disparity estimation not only in rich texture areas but also in low texture areas. The model was trained only on the Scene Flow large-scale dataset, and the disparity estimation was conducted on mainstream datasets such as Middlebury, KITTI 2015, and ETH3D. Compared with earlier stereo matching algorithms, this method not only achieves more accurate disparity estimation but also has wider applicability and stronger robustness.

Single Image Desnow Based on Vision Transformer and Conditional Generative Adversarial Network for Internet of Vehicles

With the increasing popularity of artificial intelligence applications,machine learning is also playing an increasingly important role in the Internet of Things(IoT)and the Internet of Vehicles(IoV).As an essential part of the IoV,smart transportation relies heavily on information obtained from images.However,inclement weather,such as snowy weather,negatively impacts the process and can hinder the regular operation of imaging equipment and the acquisition of conventional image information.Not only that,but the snow also makes intelligent transportation systems make the wrong judgment of road conditions and the entire system of the Internet of Vehicles adverse.This paper describes the single image snowremoval task and the use of a vision transformer to generate adversarial networks.The residual structure is used in the algorithm,and the Transformer structure is used in the network structure of the generator in the generative adversarial networks,which improves the accuracy of the snow removal task.Moreover,the vision transformer has good scalability and versatility for larger models and has a more vital fitting ability than the previously popular convolutional neural networks.The Snow100K dataset is used for training,testing and comparison,and the peak signal-to-noise ratio and structural similarity are used as evaluation indicators.The experimental results show that the improved snow removal algorithm performs well and can obtain high-quality snow removal images.

IMPROVED REGULARITY OF HARMONIC DIFFEOMORPHIC EXTENSIONS ON QUASIHYPERBOLIC DOMAINS

Let X be a Jordan domain satisfying certain hyperbolic growth conditions.Assume that φ is a homeomorphism from the boundary ?X of X onto the unit circle.Denote by h the harmonic diffeomorphic extension of φ from X onto the unit disk.We establish the optimal Orlicz-Sobolev regularity and weighted Sobolev estimate of h.These generalize the Sobolev regularity of h in [A.Koski,J.Onninen,Sobolev homeomorphic extensions,J.Eur.Math.Soc.23(2021) 4065-4089,Theorem 3.1].

钢混组合结构地铁高架车站墩柱间距影响研究

研究目的:针对长沙轨道交通某钢混组合结构高架车站首层双墩柱三种不同的布置方式进行研究,采用有限元空间整体建模对车站整体模型首层墩柱不同的间距布置方案进行地震作用及各荷载组合作用下的计算与分析。基于整体建模和结构性能化设计理念,比较双墩柱三种不同间距(1.6 m、2.6 m、3.6 m)布置条件下,钢混组合地铁高架车站结构相应的结构整体受力、墩柱及悬臂盖梁等关键构件的受力与变形差异。研究结论:(1)墩柱间距对钢混组合车站结构的整体受力性能具有较大的影响,对车站悬臂盖梁竖向变形影响较小;(2)建模分析时应尽量考虑首层两墩柱间距的影响;(3)本文研究可为现行地铁高架车站的性能化设计提供理论指导与参考。

Analytical and Experimental Study of Free Vibration of Beams Carrying Multiple Masses and Springs

The structures in engineering can be simplified into elastic beams with concentrated masses and elastic spring supports. Studying the law of vibration of the beams can be a help in guiding its design and avoiding resonance. Based on the Laplace transform method, the mode shape functions and the frequency equations of the beams in the typical boundary conditions are derived. A cantilever beam with a lumped mass and a spring is selected to obtain its natural frequencies and mode shape functions. An experiment was conducted in order to get the modal parameters of the beam based on the NExT-ERA method. By comparing the analytical and experimental results, the effects of the locations of the mass and spring on the modal parameter are discussed. The variation of the natural frequencies was obtained with the changing stiffness coefficient and mass coefficient, respectively. The findings provide a reference for the vibration analysis methods and the lumped parameters layout design of elastic beams used in engineering.

Patterns of biomass,carbon,and nitrogen storage distribution dynamics after the invasion of pine forests by Bursaphelenchus xylophilus (Nematoda: Aphelenchoididae) in the three Gorges Reservoir Region

Masson pine stands infected by Pine wilt disease(PWD) in the Three Gorges Reservoir Region of central China were surveyed to quantify the immediate responses and subsequent trajectories of biomass,carbon(C),and nitrogen(N) in stand-level major ecosystem compartments.The biomasses of above-and belowground tree components,as well as of the understory,forest floor,and mineral soil(0–40 cm),were determined within each stand.C and N storage were also estimated for each ecosystem compartment.Overstory biomass decreased steadily with the extent of PWD infection.Understory biomass ranged from1.97 to 4.16 Mg ha,and the observed value for forest floor biomass was 12.89–22.59 Mg ha.The highest mean C and N concentrations were found in the stem bark and needles of Masson pine,respectively,while the lowest were found in the semi-to fully decomposed layer of the forest floor and stem wood of Masson pine,respectively.The C and N storage of aboveground trees,tree roots,and the aboveground ecosystem decreased with the extent ofPWD infection.However,the C and N contents of the understory,forest floor,and total mineral soil initially declined after PWD infection before recovering over the following several years.Those result concluded that the biomass,C,and N storage of different forest ecosystem compartments have experienced certain variations following the PWD epidemic.This is vital to understand the shifts in stand-level C and N allocation in PWD-damaged forest stands,as well as for predicting the responses of regional and global C and N cycling.

Effect of pine wood nematode invasion on pine community functions in the Pinghu region, Zhejiang Province, eastern China

In order to investigate the effect of invastion by pine wood nematode(PWN), this study analyzed several functional indices, i.e., the increment in DBH and stand volume and biomass, in the damaged stands with various mixed percentages of Pinus massoniana and P. thunbergii and with different levels of damage. According to the results of rate of change in increment of DBH and stand volume, the forest ecosystem resistance against PWN increased with a reduction in the mixed ratio of pine. The resistance was highest with a mixed percentage of 50%. The invasion of PWN changed the corresponding relationship of increment between DBH and stand volume(pure stands > 7:3 conifer and broadleaf > 6:4 conifer and broadleaf > 5:5 conifer and broadleaf) among the P. thunbergii stands when there is no damage, but for P. massoniana stands this phenomenon did not occur. For the increment rate of DBH and stand volume, this significant change in P. thunbergii forest indicates that the resistance of pure P. thunbergii forest was higher than that of P. massoniana. The invasion of PWN accelerates the succession from pure stands to mixed stands and then to the broadleaf evergreen stands.

Effects of forest canopy density and epixylic vegetation on nutrient concentrations in decaying logs of a subalpine fir forest

Background:Deadwood and the associated epixylic vegetation influence nutrient cycles in forest ecosystems.Open canopies strongly regulate deadwood decomposition and disrupt epixylic vegetation on logs.However,it is unclear how the forest canopy density and epixylic vegetation growth affect the nutrient concentrations in deadwood.Methods:We measured the concentrations of nitrogen(N),phosphorus(P),potassium(K),calcium(Ca),sodium(Na),magnesium(Mg),and manganese(Mn)in experimentally exposed decaying logs placed in gaps,at the edge of gaps,and under the closed canopy during a four-year decomposition experiment in a Subalpine Faxon fir forest(Abies fargesii var.faxoniana)on the eastern Qinghai-Tibetan Plateau,China.To assess the effect of the epixylic vegetation,we experimentally removed it from half of the logs used in the study.Results:Under open canopy conditions in the gap and at the edge,the concentrations for most of the nutrients in the bark and the highly decayed wood were lower than under the closed canopy.The effect of the epixylic treatment on nutrient concentrations for all but K and Na in barks varied with the decay classes.Significantly lower concentrations of N,P,Ca,and Mn following the removal of epixylic vegetation were observed in the wood of decay class IV.Epixylic vegetation significantly increased most nutrient concentrations for decaying barks and wood under open canopy conditions.In contrast,epixylic vegetation had no or minimal effects under the closed canopy.Conclusions:Forest canopy density and epixylic vegetation significantly alter the nutrient concentrations in decaying logs.Open canopies likely accelerate the rate of nutrient cycling between the epixylic vegetation and decaying logs in subalpine forests.

Sipdroid平台下的信息隐藏功能设计与实现

网络电话具有资费低、易操作、平台兼容性高等优点,因此得到迅速发展并获得广大消费者的青睐。Sipdroid是一款开源且使用简便的网络电话软件,其采用的Sip协议具有结构简单、支持多媒体业务的开展、符合互联网网络结构、可扩展性好、应用灵活等优点。基于的Android平台具有良好的开源性和兼容性。网络在为人们提供信息共享的同时,对信息的安全性也造成了一定的威胁。本文为了进一步提高传输信息的安全性,在Sipdroid系统的基础上进行分析设计,添加信息隐藏模块,在实时语音通话的同时,实现了隐藏信息的嵌入、传输与提取。测试结果表明,在加入信息隐藏功能之后Sipdroid仍具有良好的使用性。

Borderline Case of Traces and Extensions for Weighted Sobolev Spaces

In this paper,we study the traces and the extensions for weighted Sobolev spaces on upper half spaces when the weights reach to the borderline cases.We first give a full characterization of the existence of trace spaces for these weighted Sobolev spaces,and then study the trace parts and the extension parts between the weighted Sobolev spaces and a new kind of Besov-type spaces(on hyperplanes)which are defined by using integral averages over selected layers of dyadic cubes.

Perceptual quantization parameter selection for crime scene investigation tool images

1 Introduction Crime scene investigation(CSI)is critical for solving criminal cases and court trials.Currently,all CSI data must be kept as electronic files in specific systems according to relevant regulations.Electronic files,including reconstructed CSI images,provides great convenience for the public security and court to store,manage,display,and analyze CSI data more effectively.Image coding which pursues higher reconstructed quality of CSI images using lower coding rate plays a very important role in the above process.Compared with the previous image coding standards,high efficiency video coding(HEVC)still image coding technique significantly improves the image coding efficiency.The coding efficiency of HEVC is closely related to the selected quantization parameter(QP).

In vitro and in vivo efficacy of Molnupiravir against Zika virus infections

Dear Editor,Zika virus(ZIKV)is a mosquito-borne,positive-stranded RNA virus first identified in 1947 in monkeys and later identified in humans in 1952(Faye et al.,2014).It is among the“TORCH”group of microorganisms and causes outbreaks in several countries and regions since 2007(Voordouw et al.,2019).

Comparison of mixing layer height inversion algorithms using lidar and a pollution case study in Baoding, China

Beijing–Tianjin–Hebei area is suffering from atmospheric pollution from a long time. The understanding of the air pollution mechanism is of great importance for officials to design strategies for the environmental governance. Mixing layer height(MLH) is a key factor influencing the diffusion of air pollutants. It plays an important role on the evolution of heavy pollution events. Light detection and ranging(lidar), is an effective remote-sensing tool, which can retrieve high spatial and temporal evolution process within mixing layer(ML), especially the variation of MLH. There are many methods to retrieve MLH, but each method has its own applicable limitations. The Mie-lidar data in Beijing was firstly used to compare three different algorithms which are widely used under different pollution levels.We find that the multi-layer structure near surface may cause errors in the detection of mixing layer. The MLH retrieved based on image edge detection was better than another two methods especially under heavy polluted episode. Then we applied this method to investigate the evolution of the mixing layer height during a pollution episode in December2016. MLH at Gucheng county showed the positive correlation with the concentration of particulate matters during the start of this pollution episode. The elevated pollution level in Gucheng was not associated with MLH's decrease, and the significantly increased particulate matters raised the boundary layer, which trapped the pollutants near the surface.

Enhancement of corrosion resistance in sintered Nd-Fe-B permanent magnet doping with different CuZn5 contents

Nd-Fe-B permanent magnets doped with CuZn5 powders were prepared via conventional sintered method. The effects of CuZn5 contents on magnetic properties and corrosion resistance of the magnets were sys- tematically studied. It shows that the remanence, coercivity, and maximum energy product decrease gradually with the increase in CuZn5 doping content. The magnet＇s corrosion kinetics in autoclaves environment and its electrochemical properties in electrolytes were also examined. It is interesting to see that the weight loss of 3.5 wt% and 4.5 wt% CuZn5 powders doping magnets is only 1 and 0 mg.cm^-2 after autoclaves test at 121 ℃, 2 × 10^5 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn5 doping. Electrochemical results show that the CuZn5 powders doping magnets display more positive corrosion potential （Eoorr） and lower corrosion current density （Icorr） than those of the original magnets without CuZn5 doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn5 powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets.

Computational Analysis of Synthetic Planning:Past and Future

Computer-aided synthesis planning(CASP)integrates intuition of chemists and reliability of computers.As an in-between of unique creativities of human beings and unparalleled calculational capability of computers,CASP has become an important tool used in academic and industrial research.With explosion of novel chemical reactions,increasing of computer performance,and revolution of algorithms,CASP will play more significant roles in the synthetic chemistry field,inspiring novel and highly efficient syntheses of natural products and drug candidates.In this article,we review the progress in computational analysis of synthetic planning from rule-based programs(e.g.,LHASA and SECS)in the early stage to machine learning(e.g.,neural networks and seq2seq methods)in more recent years.

Synthesis and photocatalytic properties of lotus-rootlike Au-ZnO nanostructures

Unique lotus-rootlike Au-Zn O hybrid structures were obtained by controlling the deposition of pre-synthesized Au nano- crystals onto the surfaces of as-obtained Zn O structures. Zn O with lotus-rootlike structures was first prepared through a hydrothermal process. We also investigated the effects of various Au contents on the photocatalytic activities in detail. Notably, compared to the pure Zn O component, these resulting lotus-root-like Au-Zn O nanostructures with the appropriate amounts of Au content exhibited better photocatalytic efficiency.

Molecular engineering of C_(x)N_(y):Topologies,electronic structures and multidisciplinary applications

As a class of metal-free two-dimensional(2D)semiconductor materials,polymeric carbon nitrides have attracted wide attention recently due to its facile regulation of the molecular and electronic structures,availability in abundance and high stability.According to the different ratios of C and N atoms in the fra mework,a series of C_(x)N_(y)materials have been successfully synthesized by virtue of various precursors,which further triggers extensive investigations of broad applications ranging from sustainable photocatalytic reactions and highly sensitive optoelectronic biosensing.In view of topological structures on their electronic structures and material properties,the as-reported C_(x)N_(y)could be generally classified into two main categories with three-or six-bond-extending frameworks.Owing to the effective n→π*transition in most C_(x)N_(y)materials,the relative energy level of the lone-pair electrons on N atoms is high,which thus endows the mate rials with the capability of visible light absorption.Meanwhile,the different repeating units,bridging groups and defect sites of these two kinds of C_(x)N_(y)allow them to effectively drive a diverse of promising applications that require specific electronic,inte rfacial and geometric properties.This review paper aims to summarize the recent progress in topological structure design and the relevant electronic band structures and striking properties of C_(x)N_(y)materials,In the final part,we also discuss the existing challenges of C_(x)N_(y)and outlook the prospect possibilities.

亚高山森林倒木碳氮磷化学计量特征随林窗位置的变化

森林林窗对太阳辐射和降水(主要是降雨和降雪)的再分配可造成林窗内外微环境条件的异质性。本研究旨在通过改变微环境,测试林窗对倒木碳(C)、氮(N)和磷(P)化学计量比的影响。在青藏高原东部的亚高山森林中,将I-V腐解等级的岷江冷杉(Abies faxoniana)倒木分别置于林窗中心(GC)、林窗边缘(GE)和郁闭林下(CC)进行原位培养,分别于2013-2016年8月测定了腐烂树皮、边材和心材的C、N、P含量。研究结果表明,树皮N浓度从CC到GC呈下降趋势,而边材和心材则表现出相反的趋势。此外,边材和心材IV、V腐解等级的C/N从CC到GC呈下降趋势,心材V腐解等级的N/P从CC到GC呈增加趋势,这表明森林林窗对高度腐解等级倒木的C/N/P化学计量比有强烈影响。简而言之,高度腐烂的倒木更容易受到微环境的影响,必要时应适当调整郁闭林下或林窗中心的高度腐烂的倒木比例。

Exploring the impact of new particle formation events on PM_(2.5) pollution during winter in the Yangtze River Delta,China

New particle formation(NPF)events are an increasingly interesting topic in air quality and climate science.In this study,the particle number size distributions,and the frequency of NPF events over Hefei were investigated from November 2018 to February 2019.The proportions of the nucleation mode,Aitken mode,and accumulation mode were 24.59%,53.10%,and 22.30%,respectively,which indicates the presence of abundant ultrafine particles in Hefei.Forty-six NPF events occurred during the observation days,accounting for 41.82%of the entire observation period.Moreover,the favorable meteorological conditions,potential precursor gases,and PM_(2.5)range of the NPF events were analyzed.Compared to non-NPF days,the NPF events preferentially occurred on days with lower relative humidity,higher wind speeds,and higher temperatures.When the PM_(2.5) was 15–20,70–80,and105–115μg/m^(3),the frequency of the NPF events was higher.Nucleation mode particles were positively related to atmospheric oxidation indicated by ozone when PM_(2.5) ranged from 15 to 20μg/m^(3),and related to gaseous precursors like SO_(2) and NO_(2) when PM_(2.5)was located at 70-80 and 105–115μg/m^(3).On pollution days,NPF events did not directly contribute to the increase in the PM_(2.5) in the daytime,however,NPF events would occur during the night and the growth of particulate matter contributes to the nighttime PM_(2.5) contents.This could lead to pollution that lasted into the next day.These findings are significant to the improvement of our understanding of the effects of aerosols on air quality.

Nitrogen-rich carbon nitrogen polymers for enhancing the sorption of uranyl

Nitrogen enrichment and increased nitrogen content is an effective strategy for enhancing adsorption of uranium by carbon nitride polymers.Herein,we reported the uranium absorption by using a structurally well-defined and nitrogen-rich carbon nitride polymer with C_(3)N_(5) stoichiometry for the first time.In comparison with the adsorption performance of g-C_(3)N_(4) for U(Ⅵ),the conjugation system of the material was increased by connecting the heptazine unit through the azo bridge in the structure of C_(3)N_(5),so that C_(3)N_(5) exhibited several times higher adsorption performance than that of g-C_(3)N_(4).The C_(3)N_(5) has high kinetics for uranyl ions,which can adsorb100 mg/g U(Ⅵ)in only 10 min and reach complete adsorption equilibrium in 60 min;the theoretical maximum adsorption capacity is 207 mg/g,meanwhile,the material exhibits high selectivity.The results of spectral analysis and theoretical calculations indicate that the process of uranyl ion capture by C3N5is a combination of physical and chemical adsorption,and its higher density of electronic states makes the electrostatic binding ability enhanced,which is favorable to the adsorption of uranyl ions by C_(3)N_(5).This work indicates that C_(3)N_(5) has great promise and application in the separation and enrichment of uranyl ions,and also provides a reference for the systematic investigation of the adsorption ability of nitrogenrich carbon nitrogen polymers on uranyl ions.