激光诱导击穿光谱(LIBS)分析虚拟仿真实验

虚拟仿真实验作为大型仪器分析实验教学模式的新兴趋势,有效地将虚拟仿真技术与实物仪器教学相结合,最大限度地提升了学生对于大型仪器分析的综合应用能力。本文以激光诱导击穿光谱(LIBS)虚拟仿真实验系统为例,完整地模拟了LIBS系统的样品处理、光谱采集、定性分析和定量分析等实际实验场景,通过虚实结合实验教学模式对实验过程进行实时跟踪与综合考评。该实验有助于提高学生自主探究能力和创新意识,培养具有独立思考与实践能力的拔尖人才。

Analysis of wheel-rail adhesion redundancy considering the thirdbody medium on the rail surface

Purpose–In response to the problem of insufficient traction/braking adhesion force caused by the existence of the third-body medium on the rail surface,this study aims to analyze the utilization of wheel-rail adhesion coefficient under different medium conditions and propose relevant measures for reasonable and optimized utilization of adhesion to ensure the traction/braking performance and operation safety of trains.Design/methodology/approach–Based on the PLS-160 wheel-rail adhesion simulation test rig,the study investigates the variation patterns of maximum utilized adhesion characteristics on the rail surface under different conditions of small creepage and large slip.Through statistical analysis of multiple sets of experimental data,the statistical distribution patterns of maximum utilized adhesion on the rail surface are obtained,and a method for analyzing wheel-rail adhesion redundancy based on normal distribution is proposed.The study analyzes the utilization of traction/braking adhesion,as well as adhesion redundancy,for different medium under small creepage and large slip conditions.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived.Findings–When the third-body medium exists on the rail surface,the train should adopt the low-level service braking to avoid the braking skidding by extending the braking distance.Compared with the current adhesion control strategy of small creepage,adopting appropriate strategies to control the train’s adhesion coefficient near the second peak point of the adhesion coefficient-slip ratio curve in large slip can effectively improve the traction/braking adhesion redundancy and the upper limit of adhesion utilization,thereby ensuring the traction/braking performance and operation safety of the train.Originality/value–Most existing studies focus on the wheel-rail adhesion coefficient values and variation patterns under different medium conditions,without considering whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train.Therefore,there is a risk of traction overspeeding/braking skidding.This study analyzes whether the rail surface with different medium can provide sufficient traction/braking utilized adhesion coefficient for the train and whether there is redundancy.Based on these findings,relevant measures for the reasonable and optimized utilization of adhesion are derived to further ensure operation safety of the train.

Karstsinnectes cehengensis(Cypriniformes:Nemacheilidae),a new species of cave fish from Guizhou,China

Four species of the genus Karstsinnectes,which live in dark,low-energy groundwater ecosystems,are currently recorded,mainly distributed in the upstream of the Pearl River,the Youjiang River and the Hongshui River.Completing biodiversity surveys is particularly difficult due to the particular cave habitats inhabited by these species.In this work,we describe a new cave fish of the genus Karstsinnectes,namely K.cehengensis Luo,Zhao&Zhou,sp.nov.,collected from the Beipanjiang River,the upstream of the Hongshui River.Genetically,the four individuals of the new species form a phylogenetically separate lineage,as the sister clade of K.acridorsalis,with a 9.4–9.5%genetic difference in mitochondrial Cyt b.Morphologically,the new species can be distinguished from its congeners by a combination of the following morphological characteristics:body naked,without body color;eyes reduced,diameter 1.4–3.8%of head length;anterior and posterior nostrils adjacent,anterior nostril not elongated to a barbel-like tip;lateral line incomplete;caudal fin forked;dorsal-fin rays iii-7,pectoral-fin rays i-11–12,pelvic-fin rays i-7,anal-fin rays iii-5,with 14 branched caudal-fin rays.The discovery of this new species represents the northernmost distribution of species within the genus Karstsinnectes and the first record from Guizhou Province.All currently known species of this genus inhabited in caves,making them ideal organisms for studying historical river connectivity and cave formation process.

AVM:A Manually Curated Database of Aerosol-transmitted Virus Mutations,Human Diseases,and Drugs

Aerosol-transmitted viruses possess strong infectivity and can spread over long distances,earning the difficult-to-control title.They cause various human diseases and pose serious threats to human health.Mutations can increase the transmissibility and virulence of the strains,reducing the protection provided by vaccines and weakening the efficacy of antiviral drugs.In this study,we established a manually curated database(termed AVM)to store information on aerosol-transmitted viral mutations(VMs).The current version of the AVM contains 42,041 VMs(including 2613 immune escape mutations),45 clinical information datasets,and 407 drugs/antibodies/vaccines.Additionally,we recorded 88 human diseases associated with viruses and found that the same virus can target multiple organs in the body,leading to diverse diseases.Furthermore,the AVM database offers a straightforward user interface for browsing,retrieving,and downloading information.This database is a comprehensive resource that can provide timely and valuable information on the transmission,treatment,and diseases caused by aerosol-transmitted viruses(http://www.bio-bigdata.center/AVM).

Excellent energy storage performance in Bi_(0.5)Na_(0.5)TiO_(3)-based lead-free high-entropy relaxor ferroelectrics via B-site modification

Next-generation advanced high/pulsed power capacitors urgently require dielectric materials with outstanding energy storage performance.Bi_(0.5)Na_(0.5)TiO_(3)-based lead-free materials exhibit high polarization,but the high remanent polarization and large polarization hysteresis limit their applications in dielectric capacitors.Herein,high-entropy perovskite relaxor ferroelectrics(Na_(0.2)Bi_(0.2)Ba_(0.2)Sr_(0.2)Ca_(0.2))(Ti1-x%Zrx%)O_(3)are designed by adding multiple ions in the A-site and replacing the B-site Ti^(4+)with a certain amount of Zr^(4+).The newly designed system showed high relaxor feature and slim polarization-electric(P-E)loops.Especially,improved relaxor feature and obviously delayed polarization saturation were found with the increasing of Zr^(4+).Of particular importance is that both high recoverable energy storage density of 6.6 J/cm^(3) and energy efficiency of 93.5%were achieved under 550 kV/cm for the ceramics of x=6,accompanying with excellent frequency stability,appreciable thermal stability,and prosperous discharge property.This work not only provides potential dielectric materials for energy storage applications,but also offers an effective strategy to obtain dielectric ceramics with ultrahigh comprehensive energy storage performance to meet the demanding requirements of advanced energy storage applications.

浙江海域海龟记录及其种群现状

东海浙江海域分布着5种海龟,分别为棱皮龟(Dermochelys coriacea)、绿海龟(Chelonia mydas)、红海龟(Caretta caretta)、玳瑁(Eretmochelys imbricata)和太平洋丽龟(Lepidochelys olivacea),均被列为国家一级重点保护野生动物。目前,针对浙江海域的海龟种群现状调查较为缺乏。为此,本研究通过搜集互联网平台上1981年4月1日至2022年12月31日的浙江海域海龟发现记录,尤其是整合了短视频平台渔民上传的影像记录这一新颖来源的数据,对浙江海域海龟种群现状进行评估。共搜集到互联网上浙江海域海龟报道109笔,共计234只,其中红海龟个体数占79.1%,绿海龟占9.4%,棱皮龟占6.0%,太平洋丽龟占4.3%,玳瑁占1.3%。5种海龟所有个体均为成体。同时,通过短视频平台获取的记录案例数最多,占总记录案例的66.1%,占近10年所有记录案例的93.6%。本研究结果表明浙江海域红海龟数量最多,绿海龟、棱皮龟和太平洋丽龟相对较少,玳瑁最少。同时,短视频数据从2020年开始急剧增多,这提示短视频数据可能是未来海洋爬行动物种群数量调查的重要数据源。

2010-2020年中华穿山甲在中国的发现记录及保护现状

中国是中华穿山甲(Manis pentadactyla)历史分布区面积和野生种群数量最大的国家。中华穿山甲曾广泛见于我国长江以南各省,但20世纪中期以来,由于其甲片被作为贵重的中药材原料,加之地下野味市场的需求,大量非法捕猎使得我国野生穿山甲经历了剧烈的分布区缩减和种群下降。目前,中华穿山甲已被列为我国一级重点保护野生动物,在IUCN红色名录中被评估为极危(CR)等级。中华穿山甲分布范围广、种群密度低、活动隐秘、调查难度大,摸清其野外分布现状是当前穿山甲研究与保护中的首要任务。为此,本研究通过检索2010–2020年间全国范围内中华穿山甲的发现记录,统计中华穿山甲的目击数量、空间分布以及后续状态,制作物种分布地图,并与历史分布情况进行对比,以评估其野生种群的分布现状与分布区变化。2010–2020年共在11个省级行政区收集到中华穿山甲确认记录142条,主要集中于大陆华东地区及台湾岛,台湾、浙江、广东三省记录位点数占全部位点数的67.6%;相较其历史分布区,西南、华南地区近年来野外确认较为匮乏。近10年来我国的中华穿山甲记录呈逐渐增多趋势,86%被发现的实体穿山甲得到救助、放归或未被干扰。本研究结果表明,目前中华穿山甲在我国,尤其是华东及台湾地区,仍具有一定数量的野生种群分布,且近年来民众对于穿山甲的认知和保护意识有了较大提高。然而,现有调查和资料仍不足以对该物种进行全面的现状评估,亟需加强对我国野生穿山甲种群的调查、监测和保护。

VR联合AR融入式教学系统在临床医学专业口腔通识医学教育的应用研究

目的研究虚拟现实(virtual reality,VR)联合增强现实(augmented reality,AR)融入式教学系统在临床医学专业口腔通识医学教育的应用与效果。方法以海军军医大学2015级临床医学五年制一教班160名本科生为研究对象,分为VR+AR组和传统组,每组各80人。对两组学生的前期成绩及授课成绩进行对比分析,并于结课后进行问卷调查分析。利用Epidata 3.0进行问卷资料输入,使用SPSS 23.0软件进行t检验、卡方检验和Fisher精确检验。结果VR+AR组与传统组在基础知识成绩上差异无统计学意义[(52.65±3.76)vs.(51.90±3.46),P=0.516],但VR+AR组在病例分析[(35.85±2.56)vs.(31.40±2.96),P<0.001]及总成绩[(88.50±4.95)vs.(83.30±4.86),P=0.002]上均高于传统组。问卷调查结果显示,VR+AR组在"教学模式"[(92.30±6.90)vs.(85.20±7.30),P<0.001]、"教学方法"[(91.70±5.90)vs.(86.00±6.70),P=0.012]和"教学提升"[(90.70±8.70)vs.(82.30±8.40),P<0.001]上评分均高于传统教学组。结论VR联合AR融入式教学系统,可提高教学成绩与教学质量,方便用于口腔狭小空间内的教学演示、模拟操作,适用于临床医学专业口腔通识医学教育。