Fine Grained Feature Extraction Model of Riot-related Images Based on YOLOv5

With the rapid development of Internet technology,the type of information in the Internet is extremely complex,and a large number of riot contents containing bloody,violent and riotous components have appeared.These contents pose a great threat to the network ecology and national security.As a result,the importance of monitoring riotous Internet activity cannot be overstated.Convolutional Neural Network(CNN-based)target detection algorithm has great potential in identifying rioters,so this paper focused on the use of improved backbone and optimization function of You Only Look Once v5(YOLOv5),and further optimization of hyperparameters using genetic algorithm to achieve fine-grained recognition of riot image content.First,the fine-grained features of riot-related images were identified,and then the dataset was constructed by manual annotation.Second,the training and testing work was carried out on the constructed dedicated dataset by supervised deep learning training.The research results have shown that the improved YOLOv5 network significantly improved the fine-grained feature extraction capability of riot-related images compared with the original YOLOv5 network structure,and the mean average precision(mAP)value was improved to 0.6128.Thus,it provided strong support for combating riot-related organizations and maintaining the online ecological environment.

INVESTIGATION ON FRACTURE BEHAVIOR FOR WELDED JOINT OF NEW GENERATION FINE GRAINED STEEL SS400

The fracture behavior for welded joint of new generation fine grained steel SS400 was investigated and assessed on the basis of fitness for purpose philosophy. The actual critical defect sizes for the SS400 base metal and its weld HAZ (heat affected zone) defined by the gross yielding criterium have been determined directly by means of wide plate tests. It has been shown that although the HAZ grain growth occurs due to the welding heat, the resistance to fracture is not deteriorated. The deformation behavior of wide plate specimen was also studied by finite, element (FE) analysis. The deformation of weld HAZ is protected by the high strength weld metal, so it is easier to get the general yielding for the welded joint specimen.

Prediction of HAZ grain size in welding of ultra fine grained steel with different parameters

The temperature field and thermal cycling curve in the heat-affected zone during welding 400 MPa ultra fine grained steel by plasma arc were simulated using finite element method. The principle of grain growth kinetics was used to predict the grain size in the heat-affected zone under different welding parameters. The simulation results show that the growing tendency of HAZ grain could be controlled by adjusting the welding parameters, but the growth of HAZ grain could not be eliminated at all. The HAZ grain size became small with increasing of the cooling rate and added with increasing of welding current, arc voltage and welding speed.

Study on improving properties of welded joints of 400 MPa ultra fine grained steel by mechanical surface hardening

The welded joints of 400 MPa ultra fine grained steel in manual arc welding were treated by mechanical surface hardening. Microstructure and mechanical properties of the treated joints were compared with those of the untreated joints, based on which, primary study on the process and principle of mechanical surface hardening was carried out. The results shows that： Grain size of HAZ increases greatly and mechanical properties of welded joint decrease obviously compared with those of base martial, but grain size in the surface layer of HAZ can be refined （the grain size is about 100 nm or so） and mechanical properties of welded joints can be improved greatly by mechanical surface hardening.

THE WEAR PERFORMANCES OF FINE GRAINED ALUMINA BALLS

The wear performance of fine grain alumina ball adding diopside as fluxing agent are reported for the first time in this paper. The ball (average grain size 3 mum) exhibits excellent toughness and low wear rates. Ploughing grooves and traces of micro-cutting occur at the place with no pore. And the wear process is mainly caused by plastic deformation mechanism. Yet, the ordinary alumina balls (average grain size 6 and 15 mum) are brittle and the wear rates are high. The intergranular and transgranular dropping pits occur, and the wear process in mainly caused by brittle fracture mechanism.

Microstructures and mechanical properties of laser welded wrought fine-grained ZK60 magnesium alloy

Fine-grained ZK60 magnesium alloy sheets of 2.0 mm in thickness were successfully joined by laser beam welding （LBW）. The effects of welding parameters including laser power and welding speed on the microstructures and mechanical properties of the joints were investigated. A sound bead, with the ultimate tensile strength （UTS） of 300 MPa and elongation of 12.0%, up to 92.5% and 65% of those of the base metal, respectively, is obtained with the optimized welding parameters. No liquation cracking is visible in the partially melted zone （PMZ） owing to the inhibitory action of the fine dispersed precipitates and the fine-grained microstructure in the as-rolled magnesium alloy sheets. The fusion zone （FZ） is featured with the equiaxed dendritic grains of the average grain size about 8 μm, which are similar to those in the heat affected zone （HAZ）, and this contributes to the relatively high joint efficiency.

Microstructure,Textures and Deformation Behaviors of Fine-grained Magnesium Alloy AZ31

Channel die compression and initial textures are used to activate different deformation mechanisms in a fine-grained magnesium alloy AZ31. The σ-ε curves, microstructures and, particularly, textures are analyzed to reveal different deformation mechanisms and to compare with those of coarse grained samples. Dominant double-prismatic slip, {1012} twinning and basal slip are detected in three types of samples, respectively, which is similar to those of coarse grained samples. The detrimental effect of shear band formation or {1011} twinning is limited in fine grained microstructure. In addition to the higher flow stress at low temperature an early decrease in flow stress at higher temperature is also found in fine-grained samples in comparison with their coarse-grained counterparts. This softening is ascribed to the early dynamic recrystallization or grain boundary glide.

Enhanced mechanical stability of ultrafine grained steel through intercritical annealing cold rolled martensite

The ultrafine grained ferritic steels possess shortage of work hardening. Fine grained high strength but low ductility due to the ferrite-martensite dual phase microstruc- ture was obtained in a microalloyed steel and low carbon steels through intercritical annealing of the cold rolled martensite. The dual phase microstructure was uniform and the ferrite grain size was smaller in the microalloyed steel resulted from the pin- ning effect of microalloyed precipitates. But ferrite grown apparently and the volume fraction of the martensite was much higher without the addition of microalloying el- ements. By introducing martensite into the fine grained ferrite, the work hardening was effectively improved, leading to better mechanical stability. As a result of the fine ferrite grain size as well as uniform distribution of the martensite, the work harden- ing was enhanced, showing better strength-ductility balance in the microalloyed dual phase steel.

Fine-grained Mg−1Mn−0.5Al−0.5Ca−0.5Zn alloy with high strength and good ductility fabricated by conventional extrusion

Mg−1Mn−0.5Al−0.5Ca−0.5Zn(wt.%)alloy was fabricated by conventional extrusion at 673 K with an extrusion ratio of 25:1,followed by aging at 473 K.The microstructure was characterized by scanning electron microscopy,electron back-scattered diffraction,and transmission electron microscopy.The mechanical properties were determined by the tensile test.The peak-aged sample shows fine recrystallized grains with an average grain size of 1.7μm.Area fraction of Al−Ca particles in the alloy increases significantly after peak aging.Meanwhile,botháañandác+añdislocations were observed to remain in the alloy after hot extrusion.Thus,the peak-aged sample exhibits simultaneously high strength and good ductility with the ultimate tensile stress,tensile yield stress,and tension fracture elongation of 320 MPa,314 MPa,and 19.0%,respectively.

Surface Ferrite Grain Refinement and Mechanical Properties of Low Carbon Steel Plates

Considering the specialities of the steel plate production, the TMCP study has been carried out with Gleeble 2000 tester to explore the possibility of fine grained ferrite in the low carbon steel plates with the chemical composition of C 0.13--0.18, Si 0.12-0.18, Mn 0.50-0. 65, P 0. 010-0. 025, and S 0. 005-0. 028. The plates with thickness of 8. 7 mm in which the ferrite grain size is smaller than 8μm have been produced by special de- formation process in the laboratory. Furthermore, the trial production of special plain carbon steel plates of 16-25 mm in thickness and 2 000- 2 800 mm in width with fine grained ferrite has been successfully carried out in the Shougang Steel Plate Rolling Plant. The ferrite grain size is 5.5-7μm in the surface layers and 9.5-15μm in the central layer respectively. The yield strength is 320- 360 MPa, tensile strength is 440-520 MPa and the elongation is 25%- 34 %. It is very important for the rolling plants to improve the low carbon steel plates＇ mechanical properties. The results show that the ferrite grains in the surface layer can be refined effectively by the appropriate rolling process, and the strength can be also increased.

Breeding and Application of Japonica CMS Line Yangfujing 7A with Fine Grain Quality, Disease Resistance and High Combining Ability in Rice

Yangfujing 7A, derived from the cross between Xu 9201A and Yangfujing 7 and its successive backcrosses, is a BT-type japonica CMS line developed by the Agricultural Institute of Riparian Region of Jiangsu Province. It shows good integrat- ed characteristics, stable male sterility, good flowering habits, high out crossing rate, strong disease resistance, fine grain quality （reaching the 1st class of national standards for fine quality rice） and high combining ability. In 2012, it was technically identified in Jiangsu Province. Its F1 hybrid combination Tongyoujingl （Yangfujing 7 A/R98）, showing high yield and good grain quality, was registered and released to commercial production by Jiangsu Crop Variety Appraisal Committee in 2013.

Microstructure Features with Ultrafined and Purified Grains for Si-Mn Hot-rolling TRIP Steel

The advanced hot-rolled transformation induced plasticity （TRIP） steel with high tensile strength of 775 MPa, high elongation of 29% and low ductile-brittle transmission temperature less than -80℃ has been developed in laboratory based on the common silicon and manganese chemical composition. The experimental results showed that the microstructures were featured with ultra fine grain size less than 5μm, appropriate retained austenite volume fraction around 11.8% and purified ferrite grain, which may result in well balanced mechanical properties for the steel.

Investigation of Microstructure of Fine Grain Cast IN718 Compressor Blade from Abroad

Fine grain cast IN718 compressor blade form abroad has been analyzed. There is no columnar grain, uniform equiaxed grain, less segregation and no porosity cast defect in essence in the section of blade body with fine grain, in which grain size is about ASTM 2 ～4. Its microstructure is approachable to that of forging. It is hopeful to achieve the goal of replacing forging by casting.

A Survey of Sediment Fineness and Moisture Content in the Soyang Lake Floodplain Using GPS Data

Soyang Lake is the largest lake in Republic of Korea bordering Chuncheon,Yanggu,and Inje in Gangwon Province.It is widely used as an environmental resource for hydropower,flood control,and water supply.Therefore,we conducted a survey of the floodplain of Soyang Lake to analyze the sediments in the area.We used global positioning system(GPS)data and aerial photography to monitor sediment deposits in the Soyang Lake floodplain.Data from three GPS units were compared to determine the accuracy of sampling location measurement.Sediment samples were collected at three sites:two in the eastern region of the floodplain and one in the western region.A total of eight samples were collected:Three samples were collected at 10 cm intervals to a depth of 30 cm from each site of the eastern sampling point,and two samples were collected at depths of 10 and 30 cm at the western sampling point.Samples were collected and analyzed for vertical and horizontal trends in particle size and moisture content.The sizes of the sediment samples ranged from coarse to very coarse sediments with a negative slope,which indicate eastward movement from the breach.The probability of a breach was indicated by the high water content at the eastern side of the floodplain,with the eastern sites showing a higher probability than the western sites.The results of this study indicate that analyses of grain fineness,moisture content,sediment deposits,and sediment removal rates can be used to understand and predict the direction of breach movement and sediment distribution in Soyang Lake.

Selective Laser Melting of Novel SiC and TiC Strengthen 7075 Aluminum Powders for Anti-Cracks Application

The aerospace and military sectors have widely used AA7075, a type of 7075 aluminum alloy, due to its exceptional mechanical performance. Selective laser melting (SLM) is a highly effective method for producing intricate metallic components, particularly in the case of aluminum alloys like Al-Si-Mg. Nevertheless, the production of high-strength AA7075 by SLM is challenging because of its susceptibility to heat cracking and elemental vaporization. In this study, AA7075 powders were mechanically mixed with SiC and TiC particles. Subsequently, this new type of AA7075 powder was effectively utilized in green laser printing to create solid components with fine-grain strengthening microstructures consisting of equiaxial grains. These as-printed parts exhibit a tensile strength of up to 350 MPa and a ductility exceeding 2.1%. Hardness also increases with the increasing content of mixed powder, highlighting the essential role of SiC and TiC in SLM for improved hardness and tensile strength performance. .

Fine-grained rock fabric facies classification and its control on shale oil accumulation: a case study from the Paleogene Kong 2 Member, Bohai Bay Basin

Lacustrine shale oil resources in China are abundant,with remarkable exploration breakthroughs being achieved.Compared to marine shale oil in North America,efficient exploration of lacustrine shale oil is more difficult;thus,selecting favorable layer and optimization zone for horizontal wells is more important.In this study,based on systematic coring of approximately 500 m fine-grained deposits of the Kong 2 Member,combining laboratory tests and log data,source rock geochemistry and reservoir physical properties,the favorable rock fabric facies for oil accumulation was analyzed and classified.First,the dominant lithologic facies,organic facies,and bed combination facies were determined based on mineral composition from logging,total organic content(TOC),and sedimentary structure.Secondly,10 fabric facies were classified by combining these three facies,with 4 fabric facies were found to have high TOC content,high total hydrocarbon,and strong fluorescence features,indicating good shale oil enrichment.Thirdly,the distribution of the upon good fabric facies was identified to be located at the top of the Kong 2 Member,with evidences of seismic resistivity inversion,thermal maturity,structure depth,and strata thickness.And the favorable facies were found to be stably distributed lateral at the area of about 100 km2.High oil flow has been detected at this layer within this area by several wells,including horizontal wells.The exploratory study of fabric facies classification and evaluation provides a new research idea for lacustrine shale oil exploration and effectively promotes breakthroughs in lacustrine shale oil exploration in Bohai Bay Basin.

铸造铝锌硅合金的性能研究

在铝锌硅合金中添加稀土后,使其合金的铸态组织得到细化,机械化能得到提高,在实验研究范围内,稀土对固溶处理后时效的硬度没有明显的影响。

Efficient fine-grained shared buffer management for multiple OpenCL devices

OpenCL programming provides full code portability between different hardware platforms,and can serve as a good programming candidate for heterogeneous systems,which typically consist of a host processor and several accelerators.However,to make full use of the computing capacity of such a system,programmers are requested to manage diverse OpenCL-enabled devices explicitly,including distributing the workload between different devices and managing data transfer between multiple devices.All these tedious jobs pose a huge challenge for programmers.In this paper,a distributed shared OpenCL memory(DSOM) is presented,which relieves users of having to manage data transfer explicitly,by supporting shared buffers across devices.DSOM allocates shared buffers in the system memory and treats the on-device memory as a software managed virtual cache buffer.To support fine-grained shared buffer management,we designed a kernel parser in DSOM for buffer access range analysis.A basic modified,shared,invalid cache coherency is implemented for DSOM to maintain coherency for cache buffers.In addition,we propose a novel strategy to minimize communication cost between devices by launching each necessary data transfer as early as possible.This strategy enables overlap of data transfer with kernel execution.Our experimental results show that the applicability of our method for buffer access range analysis is good,and the efficiency of DSOM is high.

TopicBubbler:An interactive visual analytics system for cross-level fine-grained exploration of social media data

How to explore fine-grained but meaningful information from the massive amount of social media data is critical but challenging.To address this challenge,we propose the TopicBubbler,a visual analytics system that supports the cross-level fine-grained exploration of social media data.To achieve the goal of cross-level fine-grained exploration,we propose a new workflow.Under the procedure of the workflow,we construct the fine-grained exploration view through the design of bubble-based word clouds.Each bubble contains two rings that can display information through different levels,and recommends six keywords computed by different algorithms.The view supports users collecting information at different levels and to perform fine-grained selection and exploration across different levels based on keyword recommendations.To enable the users to explore the temporal information and the hierarchical structure,we also construct the Temporal View and Hierarchical View,which satisfy users to view the cross-level dynamic trends and the overview hierarchical structure.In addition,we use the storyline metaphor to enable users to consolidate the fragmented information extracted across levels and topics and ultimately present it as a complete story.Case studies from real-world data confirm the capability of the TopicBubbler from different perspectives,including event mining across levels and topics,and fine-grained mining of specific topics to capture events hidden beneath the surface.

Microstructure and mechanical properties of high-strength low alloy steel by wire and arc additive manufacturing

A high-building multi-directional pipe joint(HBMDPJ)was fabricated by wire and arc additive manufacturing using high-strength low-alloy(HSLA)steel.The microstructure characteristics and transformation were observed and analyzed.The results show that the forming part includes four regions.The solidification zone solidifies as typical columnar crystals from a molten pool.The complete austenitizing zone forms from the solidification zone heated to a temperature greater than 1100℃,and the typical columnar crystals in this zone are difficult to observe.The partial austenitizing zone forms from the completely austenite zone heated between Ac1(austenite transition temperature)and1100℃,which is mainly equiaxed grains.After several thermal cycles,the partial austenitizing zone transforms to the tempering zone,which consistes of fully equiaxed grains.From the solidification zone to the tempering zone,the average grain size decreases from 75 to20μm.The mechanical properties of HBMDPJ satisfies the requirement for the intended application.