乌什 M_(S)7.1地震序列及应力降特征研究

研究乌什M_(S)7.1地震序列时间和空间变化以及震源参数特征,结果表明地震余震主要分布在主震北东和南西两侧,展布与迈丹断裂的走向基本吻合。目前序列b值为0.67,h值为1.3,p值为1.28。震源机制解为逆冲型,应力降处于低值水平,序列衰减基本正常。此次地震为主震—余震型,最大余震为M_(S)5.8地震。

基于YOLOv5s的轻量化架空输电线路鸟巢检测网络

架空输电线路上的鸟巢侵占会对铁塔上的电力设备造成安全隐患,间接可能影响整个电力系统的稳定运行。针对目前架空输电线路鸟巢检测模型在复杂场景以及小目标场景下检测精度不高,检测效率低,模型复杂等问题。本研究提出一种基于YOLOv5s框架的轻量化架空输电线路鸟巢检测网络。首先在主干部分采用Fasternet重构YOLOv5s特征提取网络,降低模型复杂度,提高运行速度;然后在特征融合网络部分嵌入ConvMixer层,ConvMixer层的结构设计有助于在特征信息中更好的捕捉空间和通道的关系,提升模型对于小目标的检测能力;最后在特征融合网络部分引入ODConv模块,令送入检测头的特征图包含更多有效特征,提高模型对复杂场景和小目标的检测性能。实验结果表明,本文与基线模型YOLOv5s相比,计算量和模型体积分别减少了86%和72%,平均精度均值达到96.4%,检测速度达到104.2帧/s,验证了本文改进模型的有效性和可行性。

2021年漾濞M_(S)6.4地震序列前后震源参数

利用漾濞地区共22个固定和流动台站记录到的数字地震波形资料,在扣除地震波衰减与台站场地响应后,联合反演计算得到2021年漾濞M_(S)6.4地震序列前后共819次M L≥1.0地震的震源参数,并对M L2.9~3.8地震应力降的时空演化过程进行分析。结果显示:①漾濞地震序列的地震矩与震级相关性较好,与破裂尺度之间存在一定的正相关关系,与拐角频率之间呈现出负相关关系,对于M L≤2.8的地震,应力降随震级增大而增大,而对于M L>2.8的地震,其应力降随震级的变化趋势并不明显;②漾濞M_(S)6.4地震序列前后的应力降受漾濞区域复杂构造环境背景的控制表现明显的分段特征,在前震序列阶段,震源区中段应力降有逐渐增强的趋势,处于应力加速积累的过程,一系列高度丛集的中小地震活动所造成的应力扰动可能导致了震源区北段漾濞M_(S)6.4主震的发生;M_(S)6.4主震发生以后,其余震序列活动自北西段向南东向破裂了整个余震区,余震区北西段由于主震的发生,该区域应力背景快速调整,应力降的时空分布表现为高值-低值起伏的状态;余震区中段至最大前震震中附近区域可能由于前震活动频繁,应力释放较多,表现为应力降相对低值区域;余震区南段则余震活动丰富,为应力降高值分布区域。漾濞地震序列中震级较大的地震活动与应力降高值区域一致性较好。

Association of <i>Ammodramus bairdii</i>A. 1844, and Other Species of Grassland Granivorous Birds in Winter Time in Northwestern Mexico

During the winter of 2009 grassland birds were monitored in the region of Cuchillas de la Zarca to estimate the association betweenAmmodramus bairdiiAudubon 1844, focal species of grassland and bird species belonging to the trophic guild of grassland granivorous birds (n = 25 ). The study area was divided into monitoring quadrants (n = 16) where 96 transects for bird monitoring were conducted, recording 16,635 individuals of which only 32.9% were in the trophic guild of grassland granivorous birds. The association betweenA. bairdiiand other species was estimated from the nonparametric statistical index of Kendall’s coefficient of concordance (W) and the p value, through permutation analysis (n = 10,000), finding positive and significant associations (p≤0.05) of the target species for study withSturnella magna,Passerculus sandwichensisandAmmodramus savannarum, species that share habitat preferences of natural grassland in good condition, slightly grazed and with little tolerance to the shrub cover. The association W ranged from 0.072 and 0.749. These results can recognize this region as an important area for the conservation of obligate grassland birds during winter, suggesting establish training programs to better utilize this resource by means of cattle activity.

Enzymatic recovery of glycopeptides from different industrial grades edible bird’s nest and its by-products:nutrient,probiotic and antioxidant activities,and physicochemical characteristics

This study was conducted to recover edible bird’s nest(EBN)hydrolysates from different grades of EBN,including the industrial by-products,using enzymatic treatment.The nutrient,physicochemical properties and antioxidant activities of the recovered hydrolysates at different hydrolysis times were evaluated.Results showed that the recovery yield of enzymatic hydrolysis was above 89%for all grades of EBN and the degree of hydrolysis increased over time.Nitrite content(0.321-0.433 mg/L)was below the permissible tolerance level for all samples.Interestingly,the antioxidant activities(DPPH and ABTS scavenging activities and ferric reducing antioxidant powder(FRAP)activity)were significantly higher(P≤0.05)in hydrolysates recovered from EBN by-products(EBNhC and EBNhD)as compared to the high grade EBN hydrolysates(EBNhA and EBNhB).The in-vitro probiotic activity of EBN and its hydrolysates were examined using the probiotic bacterium Lactobacillus plantarum.Evidently,EBN by-products hydrolysate(EBNhD)recorded the highest number of L.plantarum(1.1×1011 CFU/mL),indicating that low grade EBN has the potential as prebiotic material that promotes probiotic activity.This study demonstrated the concept of using EBN by-products hydrolysates for various applications,such as functional ingredients with enhanced bioactivities,to improve its economic value.

Influence of Dropping scales of E7/6 Comber on Process Performance

The dropping scales is an important parameter for comber noil and combing quality. Because the rocking of the nipper shaft makes the nippers move backward and forward through a series of links, the original position of nipper frame is altered when changing the dropping scales, the other parameters of combing are changed accordingly. In this paper, the timing of opening-closing on nipper, the timing of cylinder’s combing, the timing of detaching-lapping and variation of nip pressure are calculated and their effects on combing are analyzed in different dropping scales on E7/6 comber.

立足教材基础 培养学生能力——三年级下册Unit 4 Where’s the bird? (Story time)教学设计

【教材简解】本单元的核心教学内容是"询问物品的位置"。要求学生在一定情景下能正确使用核心句型Where’s...?It’s....进行交谈。Story time共有七个场景,主要描述小鸟停在教室里的不同位置。在对话中出现了本单元的重点句型,即询问及回答地点。教学应与日常生活联系起来,培养学生的主动性思维和与人交流的能力。【目标预设】1.能初步感知新的语言知识:(1)单词:a bird,a desk,a chair,in,on,under。

On the Weak Drop Property for Polar of Closed Bounded Convex Sets

We define and study the weak drop property for the polar of a closed bounded convex set in a Banach space which is both a generalization of the weak drop property for dual norm in a Banach space and a characterization of the sub-differential mapping x →(?)p(x) from S(X) into 2S(X) that is norm upper semi-continuous and norm compact-valued.

True cicadas (Cicadidae) as prey for the birds of the Western Palearctic: a review

Background:True cicadas(Cicadidae)are large and temporarily abundant insects.Their availability may produce demographic and behavioural effects on bird populations,as happens with forest avifauna feeding on periodical cicadas in North America.In Europe,the Near East and North Africa,knowledge of cicada predation by birds is sparse.Methods:To help fill this gap,I consulted Cramp’s Birds of the Western Palearctic,conducted a search of online databases and used search engines to generate a database of Western Palearctic birds known to eat cicadas.Results:A total of 105 species(16%of those occurring in the region)belonging to 13 orders,and comprising 20 of the 33 passerine families,were found to consume cicadas.I estimated that 69 of these bird species are known to consume cicadas within the limits of the Western Palearctic.Many terrestrial birds predate on cicadas,preferably on adults.Avian predators include cuckoos,owls,bee-eaters,woodpeckers,falcons,reed-warblers,larks,crows and jays,buntings,shrikes,pipits and wagtails,flycatchers and chats,tits,sparrows,leaf-warblers,starlings,warblers and thrushes,but also terns and gulls.Nymphs are consumed by some passerines,owls and herons.Cicadas can make up as much as 70%of food items delivered to nestlings.Analysis of stomach contents and neck collar samples are the most common methods used in diet studies.Conclusions:Available knowledge is biased towards species that have been more intensively studied,and often lack proper quantification of prey items.More studies about the relative importance of cicadas as prey for birds in the Western Palearctic are needed.I suggest using non-invasive studies based on pellets and droppings and prioritizing declining bird species.

A Survey of Wild Birds Trading in the Beijing Bird Markets

Birds are an indispensable part of nature andthey play an important role in maintaining an ecologicalbalance. The existence of bird markets undoubtedlyposes a threat to the population of wild birds. Thegeographical location of Beijing is paramount to themigratory birds. The species of birds are rich in varietyand its quantity is large in scale. In addition, the birdmarket in old town Beijing has a long history - since theQing Dynasty, it has been the main bird market in thecity. Therefore, a survey of the major bird markets inthe city is highly representative. This study investigatedthe types, quantities, and prices of wild birds tradedin several major bird markets in Beijing from July16 to July 18, 2019. Data analysis and collation werealso conducted in this study. The results of the surveypresented 26 kinds of wild birds, with a total tradingvolume of an estimated 253. They are mainly birdsof the order of the passerine, 18 of which are underBeijing’s second-class protection, and one of them isunder first-class protection.

Experimental Base of an Innovation S-Channel to Reduce MHD Pressure Drop

Consequent on MHD geometry sensibility phenomena was measured in an accident case;the more detail experiments have been conducted at the liquid metal experimental loop upgrade facility (LMEL-U). The experimental results indicate that MHD pressure drop can be greatly reduced in the special designed ducts. Base on the experimental data, an innovation channel concept (tentatively called as the secondary flow channel, short in “S-channel”) is addressed as a reducing MHD pressure drop channel for the application of a liquid metal blanket system in fusion reactor. It may be a dawn for solving MHD pressure drop key issue of liquid metal blanket system.

Novel Computer-Aided Diagnosis System for the Early Detection of Alzheimer’s Disease

Aging is a natural process that leads to debility,disease,and dependency.Alzheimer’s disease(AD)causes degeneration of the brain cells leading to cognitive decline and memory loss,as well as dependence on others to fulfill basic daily needs.AD is the major cause of dementia.Computer-aided diagnosis(CADx)tools aid medical practitioners in accurately identifying diseases such as AD in patients.This study aimed to develop a CADx tool for the early detection of AD using the Intelligent Water Drop(IWD)algorithm and the Random Forest(RF)classifier.The IWD algorithm an efficient feature selection method,was used to identify the most deterministic features of AD in the dataset.RF is an ensemble method that leverages multiple weak learners to classify a patient’s disease as either demented(DN)or cognitively normal(CN).The proposed tool also classifies patients as mild cognitive impairment(MCI)or CN.The dataset on which the performance of the proposed CADx was evaluated was sourced from the Alzheimer’s Disease Neuroimaging Initiative(ADNI).The RF ensemble method achieves 100%accuracy in identifying DN patients from CN patients.The classification accuracy for classifying patients as MCI or CN is 92%.This study emphasizes the significance of pre-processing prior to classification to improve the classification results of the proposed CADx tool.

Spilled gallstone mimicking metastasis from cervix cancer on positron emission tomography–computed tomography

BACKGROUND Spilled gallstones from previous cholecystectomy is not an uncommon situation.It may further mimic neoplastic disease and can be misled by fluorine 18 fluorodeoxyglucose position emission tomography with computed tomography([18F]FDG PET/CT).CASE SUMMARY A 63 year-old patient was diagnosed with a cancer of the cervix.Pretreatment[18F]FDG PET/CT showed a peritoneal lesion suspicious for metastasis.Surgical exploration and histologic examination revealed the lesion to be a spilled gallstone from a previous cholecystectomy.CONCLUSION[18F]FDG PET/CT carries pitfalls since benign conditions such as intraperitoneal gallstones may be confused as malignant lesions.This case highlights the importance to be aware of the possible implications of dropped gallstones for the future,minimize its occurrence,and make all efforts to properly evaluate cancer staging,particularly for the cervix cancer.

S Zorb装置反应器过滤器压力降与滤芯性能分析

中国石油化工股份有限公司镇海炼化分公司有1.5 Mt/a(1号S Zorb)及1.2 Mt/a(2号S Zorb)两套S Zorb装置,运行末期两套装置反应器过滤器压力降分别为33 kPa与100 kPa。除了滤芯数量外,两者在运行参数、滤芯本体成分及吸附剂成分上均无明显差别。为探究两者压力降差别较大的本质原因,通过解剖两套反应器过滤器滤芯分别对其进行了各类分析。外观分析表明滤芯结构完整,未发生生锈现象,发现不同压力降下滤芯的孔隙及渗透性有较大差别。压溃强度实验发现滤芯强度均满足要求。孔径及渗透性分析表明低压力降时吸附剂主要分布在滤芯外表面,但高压力降时吸附剂渗入滤芯内部,导致渗透性大幅下降且难以通过反吹恢复。滤芯外表面能谱分析表明滤芯外表面物质为吸附剂,滤芯本身未发生硫化腐蚀。

“研究生被退学”原因分析与应对策略

近年来,“研究生被退学”现象在我国高校中频繁出现,引发社会的广泛关注。该文从多元视角对“研究生被退学”的原因、影响以及应对策略进行深入剖析,旨在揭示这一现象背后的深层次问题,以期为我国研究生教育的改革与发展提供有益的参考和启示。

Effect of Six Different Acoustic Frequencies on Growth of Cowpea(Vigna unguiculata)during Its Seedling Stage

[Objective] The aim was to study the effects of sound waves with different types and frequency characteristics on the growth of cowpea（Vigna unguiculata）during seedling stage.[Method] The insect-music mixed sound（MI）,cuckoo acoustic song,cricket acoustic song,single 400 Hz frequency sound wave,F5 and Fn sound waves composed of different frequencies were designed to investigate their effects on height and weight of cowpea seedling,and experimental data were statistically analyzed and multiple-compared by EXCEL.[Result] After treatment by sound waves with six different types and frequencies,the growth situations of cowpea were better than that in control.This indicated that sound waves could significantly promote height growth of plant.The treatments with good growth-promotion effect included 400 Hz frequency sound wave,cuckoo acoustic song and cricket acoustic song,followed by MI,Fn and F5.Cuckoo and cricket acoustic song treatment could promote the weight of cowpea seedling during seedling stage.[Conclusion] Sound waves with different types and frequency characteristics had significant growth-promotion effect on growth of cowpea during seedling stage,but their effects were different.

S型规整填料的流体力学与传质性能

通过对4种不同比表面积S型金属丝网波纹填料进行冷模实验,研究分析了S型填料的流体力学和传质性能,并把其性能与同比表面积的金属丝网波纹填料进行了对比。研究表明,S型填料具有较小的塔压降,当F=1.2(m/s).(kg/m3)0.5时,S800的干塔压降比CY800降低了40.02%;当F=1.2(m/s).(kg/m3)0.5、L=25.46 m3/(m2.h)时,S800的湿塔压降较CY800降低了78.18%。S型与CY型填料相比具有较大的液泛气速,S800的液泛气速较CY800增加了22.22%以上;另外,S型填料具有较高的传质效率,S800型填料的理论级数每米最高可达到20块/m,当L=25.46 m3/(m2.h),F≤1.5(m/s).(kg/m3)0.5时,S800的理论级数较CY800提高了12.33%以上,传质效率较传统填料有很大程度的提高。S型填料的流体力学和传质性能均较好,能同时满足高通量、低压降、高效率等生产要求,有很好的应用前景。

基于鸟瞰图融合的多级旋转等变目标检测网络

随着自动驾驶系统的发展,针对道路场景下的3D目标检测受到研究人员的广泛关注。然而,大多数基于单一传感器或者多传感器融合的目标检测方法未考虑实际道路场景中车辆旋转,使得捕获的场景同步旋转,从而导致目标检测性能降低。针对这类问题,提出一种基于多传感器融合的多级全局旋转等变目标检测网络架构,以缓解场景旋转造成的目标检测困难,从而提高目标检测性能。首先,对体素内部进行各点之间距离编码,增强局部点云几何信息,并提取体素的全局旋转等变特征;其次,引入图像的语义信息并提取全局旋转等变特征,进一步提高网络性能;最后,将具有旋转等变性的点云和图像信息在鸟瞰图上进行融合,并嵌入群等变网络提取融合鸟瞰图级全局旋转等变特征。实验结果表明,该网络架构在nuScenes验证集上达到了68.7%的平均精度均值(mAP)和71.7的nuScenes检测分数(NDS),以及平均角度误差均值(mAOE)降低到0.288,相比主流的目标检测方法,其实现了网络架构本身的旋转等变性并在性能上得到了提升,此外,各个组件对于整体网络架构的目标检测性能提升都起到了重要作用。