基于高频激光除漆的LIBS监测平台设计与应用研究

基于激光诱导击穿光谱(LIBS)技术的飞机漆层清洗监测,需要对峰值功率密度范围进行限定,以确保等离子体激发和漆层清洗的稳定性。然而,对于广泛使用的高频(kHz级)脉冲激光除漆技术,其峰值功率密度相对偏低,除漆过程中等离子体激发受到限制;且高频激光烧蚀材料产生的强连续背景光谱干扰了等离子体光谱采集。论文依据蒙皮功能漆层可控清洗需求,基于LabVIEW嵌入式开发系统的控制软件编写及激光清洗、光谱采集、控制与显示模块的集成,设计了一款适用于高频激光除漆的LIBS监测平台。选取2024-T3铝合金双漆层试样作为研究对象,采集波长介于360~700nm范围内的漆层/基体体系光谱(面漆层:Tc;底漆层:Pr;基体:As)。采用平滑滤波,基线校正和归一化对原始光谱进行预处理,并选取12条特征谱线进行主成分分析(PCA),其降维数据作为线性判别分析(LDA)的输入变量,以此建立PCA-LDA判别模型。最后将所建模型导入LIBS监测平台,通过试验验证了高频激光除漆LIBS监测平台的分类准确性。结果表明:仅以累积方差解释率大于85%作为主成分选取原则,不能满足除漆过程LDA的分类需要;通过优化LDA的主成分个数,最终选取前9个主成分作为LDA的输入,显著提升了LIBS平台的检测准确率,此时基于LIBS光谱的PCA-LDA模型分类准确率达92.5%。由此可见,设计的高频激光除漆LIBS监测平台能够完成漆层/基体体系不同结构层的材料识别,从而实现了高频脉冲激光可控除漆的有效监测。

基于LIBS数据流盘的飞机蒙皮激光除漆在线监测判据研究

等离子体产生及演化过程易受基体效应、环境噪声、脉冲能量抖动等影响,导致光谱数据具有不稳定性,从而难以保证以单条谱线为依据建立的监测判据的有效性。以连续多幅LIBS光谱为对象,并结合统计学方法建立的监测判据,可有效提升基于LIBS技术的除漆效果监测精度。论文基于搭建的高频纳秒红外脉冲激光除漆LIBS在线监测平台,实时采集了除漆过程的连续多幅LIBS光谱。光谱数据经基线矫正、归一化预处理后,依据面漆、底漆、铝合金基体光谱特征峰差异,并结合材料成分信息,选定BaⅠ(712.55 nm)、CrⅠ(357.48 nm)、CrⅠ(425.43 nm)、TiⅠ(427.45 nm)、CuⅡ(309.76 nm)、CuⅠ(484.22 nm)6条谱线作为特征谱线并监测除漆效果。研究不同除漆效果中6条特征谱线强度变化规律,建立不同除漆效果与所选特征谱线强度变化区间的映射关系。提取每幅谱线的上述6条特征谱线强度作为一组数据单元、将连续10幅谱线的数据单元作为一组数据集,除漆过程中随时间变化的每10组迭代数据集称为数据流盘。对数据流盘中的数据单元、数据集进行分析,结合置信区间,实时判定除漆区域除漆效果,获得基于数据流盘的监测判据。结果表明:该判据可有效监测仍在面漆、面漆完全去除、仍在底漆、底漆完全去除、基体损伤5类除漆效果。依据SRM手册对漆层去除效果的要求,选择面漆完全去除、基体损伤两类除漆效果展示了验证过程,三维微观形貌分析结果与LIBS数据流盘监测判据所得除漆效果结论一致。其中,面漆去除后三维微观形貌分析表明,面漆完全去除精度达1.2μm,有效验证了基于LIBS数据流盘监测判据的适用性及稳定性。

An efficient method for constructing a random insertional mutant library for forward genetics in Nannochloropsis oceanica

Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from scratch.Exogenous genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-strand breaks of DNA,causing insertional mutation.The random insertional mutant library constructed using this method has become a method of forward genetics for gene cloning.However,the establishment of a random insertional mutant library requires a high transformation efficiency of exogenous genes.Many microalgal species show a low transformation efficiency,making constructing random insertional mutant libraries difficult.In this study,we established a highly efficient transformation method for constructing a random insertional mutant library of Nannochloropsis oceanica,and tentatively tried to isolate its genes to prove the feasibility of the method.A gene that may control the growth rate and cell size was identified.This method will facilitate the genetic studies of N.oceanica,which should also be a reference for other microalgal species.

MiR-155靶向talin-1基因调控柱状黄杆菌胞外多糖诱导的EPC细胞凋亡

为研究miR-155在柱状黄杆菌胞外多糖(FC-EPS)诱导的细胞凋亡中的作用机制,本实验采用RNA干扰(RNAi)技术,通过过表达miR-155和敲降踝蛋白基因(talin-1),皆能抑制FC-EPS诱导的细胞凋亡,并鉴定出talin-1为miR-155的靶蛋白。在FC-EPS诱导细胞凋亡的过程中,踝蛋白水平显著升高,在凋亡发生阶段检测到凋亡执行蛋白Caspase-3的活化,同时检测到2条踝蛋白剪切异构体,大小分别约为200 ku和250 ku;将构建的鲤Talin-1真核表达质粒转染鲤上皮瘤细胞(EPC),过表达的Talin-1延迟且延长了细胞凋亡的进程,并检测到上述2条踝蛋白异构体。然而,当以FC-EPS转染EPC细胞时,Talin-1先下降再恢复到正常水平,细胞不发生凋亡。因此,在FC-EPS诱导细胞凋亡的过程中,细胞通过上调miR-155来调控靶基因talin-1 mRNA和蛋白转录的变化,以及产生Talin-1蛋白异构体来抑制细胞发生凋亡。本研究为有效防治柱状黄杆菌疾病提供新思路。

Different bactericidal abilities of plasma-activated saline with various reactive species prepared by surface plasma-activated air and plasma jet combinations

Plasma-activated water(PAW),as an extended form of cold atmospheric-pressure plasma,greatly expands the application of plasma-based technology.The biological effects of PAW are closely related to the aqueous reactive species,which can be regulated by the activation process.In this study,surface plasma-activated air(SAA)and a He+O_(2)plasma jet(Jet)were parallelly combined(the SAA+Jet combination)or sequentially combined(the SAA→Jet combination and the Jet→SAA combination)to prepare plasma-activated saline(PAS).The PAS activated by the combinations exhibited stronger bactericidal effects than that activated by the SAA or the Jet alone.The concentrations of H_(2)O_(2)and NO_(2)^(-)were higher in the PAS activated by the Jet→SAA combination,while ONOO^(-)concentrations were close in the three kinds of PAS and^(1)O_(2)concentrations were higher in the PAS activated by the SAA+Jet combination.The analysis of scavengers also demonstrated that H_(2)O_(2),^(1)O_(2),and ONOO^(-)in the PAS activated by the SAA+Jet combination,and^(1)O_(2)in the PAS activated by the Jet→SAA combination played critical roles in bactericidal effects.Further,the effective placement time of the three PAS varied,and the PAS activated by the Jet→SAA combination could also inactivate 2.6-log_(10)of MRSA cells after placement for more than 60 min.The regulation of reactive species in plasma-activated water via different combinations of plasma devices could improve the directional application of plasma-activated water in the biomedical field.

Time-energy distribution of photoelectron from atomic states with different magnetic quantum numbers in elliptically polarized laser fields

A Wigner-distribution-like(WDL)function based on the strong-field approximation(SFA)theory is used to investigate the ionization time of the photoelectron emitted from the initial states with different magnetic quantum number m in elliptically polarized electric fields.The saddle-point method is adopted for comparisons.For different m states,a discrepancy exists in the WDL distributions of the photoelectrons emitted in a direction close to the major axis of the laser field ellipse.Based on the saddle-point analysis,this discrepancy can be ascribed to the interference between electrons ionized from two tunneling instants.Our results show that the relationships between the tunneling instants and kinetic energy of photoelectrons are the same for different m initial states when the Coulomb potential is not considered.Our work sheds some light on the ionization-time information of electrons from different magnetic quantum states.

The Rights to Claim for Industrial Injury Compensation and Tort Compensation are Applicable to the Law:Taking Fu and Li v.a Passenger Transport Company as an Example

In the case of third-party tort,due to the lack of clear and detailed provisions on the treatment of employee’s industrial injury insurance payment and tort damage compensation,the judicial theory and practice have brought many disputes.Through combing the current relevant laws and regulations,it can be found that the application of the two systems will lead to the overlapping of industrial injury compensation.This paper analyzes the problems arising from the concurrence of industrial injury compensation and tort compensation using the case of Fu and Li v.a passenger transport company,and puts forward some ideas and suggestions on how to improve the settlement measures of such cases.

基于PCA-SVM的飞机蒙皮激光分层除漆LIBS在线监测研究

飞机蒙皮激光除漆过程的在线监测,是实现分层可控除漆、满足适航维修要求的重要手段,也是推进激光除漆工程应用、飞机维修自动化的核心技术。激光诱导击穿等离子体光谱(LIBS)技术可通过激光材料作用过程中产生的等离子体发射光谱快速分析材料表面元素变化,实现激光清洗表面状态的在线监测。基于搭建的高频纳秒红外脉冲激光除漆LIBS在线监测平台,分别采集了不同激光功率下,面漆、底漆、铝合金基体去除过程中的3类LIBS光谱(各100幅)。分析了不同激光功率下,各类光谱示踪元素特征谱线的变化情况,初步筛选了12条特征谱线作为光谱识别的特征。进一步对这12个特征进行主成分分析(PCA),并将前3个主成分(PC1、 PC2、 PC3)构成的数据集作为支持向量机(SVM)识别模型的输入量,建立了3类光谱的识别模型。形成了多漆层结构激光分层可控清除过程的LIBS在线监测判定规则,并对该规则的有效性进行了实验验证。结果表明,与低频脉冲激光单点作用采集的针状LIBS光谱相比,基于该平台采集的LIBS光谱普遍存在较强的连续背景(大于5 000 a.u.)以及1.5 nm左右的半峰全宽;针对此类光谱设计了改进均值平滑滤波算法,在去除背景光谱的同时有效避免了特征谱线强度失真;示踪元素的特征谱线存在不稳定性;主成分分析中前3个主成分PC1、 PC2、 PC3对光谱的解释率达95%,在其构成的三维空间中,同类光谱呈区域性聚集;PCA-SVM模型对训练集、测试集的识别准确率分别为99.44%、 100%;验证实验结果表明3类光谱的识别模型与在线监测判定规则有效。所建立的识别模型与判定规则,可为飞机蒙皮激光分层除漆过程监测及自动化解决方案提供核心技术支撑。

新文科背景下管理学科拔尖创新人才培养模式研究

管理学科人才培养模式改革和创新是新文科建设的重要内容,也是国家战略和社会发展的必然要求。文章从新文科背景下管理学科拔尖创新人才培养新内涵出发,探讨了人才培养的逻辑与路径。进而,结合笔者教学改革实践工作,提出了一套“一二三”式培养理念,即以国家和社会需求以及学科和产业发展趋势为导向,充分利用教育资源与国际高水平学术交流两个平台,以德育知识、专业知识和素质拓展三个模块协同培养,并从课程创新、科研创新、实践创新角度构建了“六位一体”人才培养模式。

Novel wine in an old bottle:Preventive and therapeutic potentials of andrographolide in atherosclerotic cardiovascular diseases

Atherosclerotic cardiovascular disease(ASCVD)frequently results in sudden death and poses a serious threat to public health worldwide.The drugs approved for the prevention and treatment of ASCVD are usually used in combination but are inefficient owing to their side effects and single therapeutic targets.Therefore,the use of natural products in developing drugs for the prevention and treatment of ASCVD has received great scholarly attention.Andrographolide(AG)is a diterpenoid lactone compound extracted from Andrographis paniculata.In addition to its use in conditions such as sore throat,AG can be used to prevent and treat ASCVD.It is different from drugs that are commonly used in the prevention and treatment of ASCVD and can not only treat obesity,diabetes,hyperlipidaemia and ASCVD but also inhibit the pathological process of atherosclerosis(AS)including lipid accumulation,inflammation,oxidative stress and cellular abnormalities by regulating various targets and pathways.However,the pharmacological mechanisms of AG underlying the prevention and treatment of ASCVD have not been corroborated,which may hinder its clinical development and application.Therefore,this review summarizes the physiological and pathological mechanisms underlying the development of ASCVD and the in vivo and in vitro pharmacological effects of AG on the relative risk factors of AS and ASCVD.The findings support the use of the old pharmacological compound(‘old bottle’)as a novel drug(‘novel wine’)for the prevention and treatment of ASCVD.Additionally,this review summarizes studies on the availability as well as pharmaceutical and pharmacokinetic properties of AG,aiming to provide more information regarding the clinical application and further research and development of AG.

mTORC1 signaling pathway regulates tooth repair

Tooth germ injury can lead to abnormal tooth development and even tooth loss,affecting various aspects of the stomatognathic system including form,function,and appearance.However,the research about tooth germ injury model on cellular and molecule mechanism of tooth germ repair is still very limited.Therefore,it is of great importance for the prevention and treatment of tooth germ injury to study the important mechanism of tooth germ repair by a tooth germ injury model.Here,we constructed a Tg(dlx2b:Dendra2-NTR)transgenic line that labeled tooth germ specifically.Taking advantage of the NTR/Mtz system,the dlx2b+tooth germ cells were depleted by Mtz effectively.The process of tooth germ repair was evaluated by antibody staining,in situ hybridization,Ed U staining and alizarin red staining.The severely injured tooth germ was repaired in several days after Mtz treatment was stopped.In the early stage of tooth germ repair,the expression of phosphorylated 4E-BP1 was increased,indicating that mTORC1 is activated.Inhibition of mTORC1 signaling in vitro or knockdown of mTORC1 signaling in vivo could inhibit the repair of injured tooth germ.Normally,mouse incisors were repaired after damage,but inhibition/promotion of mTORC1 signaling inhibited/promoted this repair progress.Overall,we are the first to construct a stable and repeatable repair model of severe tooth germ injury,and our results reveal that mTORC1 signaling plays a crucial role during tooth germ repair,providing a potential target for clinical treatment of tooth germ injury.

线上线下双模式教育的应用——以机械电子工程专业必修课《热力学与传热学基础》为例

后疫情时代,为适应教学要求,逐渐衍生出线上线下双模式的教学方式。本文以机械电子工程专业的必修课《热力学与传热学基础》为例介绍了线上线下双模式教育在教学中的应用。首先介绍了《热力学与传热学基础》这门专业必修课的主要授课内容、学习目标和考核标准,其次以理想气体基本热力学过程的p-v图和T-s图为例,说明了双模式教育的应用为教学带来的好处。

基于圆弧刀补偿加工的平面调制切削技术研究

针对尖刀加工的平面调制微结构表面质量差以及尖刀顶部尖角易磨损的现象,本文系统分析了尖刀在加工平面调制结构时轮廓误差的形成机理,发现了尖刀加工调制表面的轮廓误差大且存在难以补偿的特性,调制结构的轮廓误差与刀尖宽度成正比,与调制的周幅比值(λ/a)成反比.为此,本文提出了采用圆弧刀具结合刀具半径补偿方法以降低平面调制样品轮廓误差的技术方案.实验结果表明,采用圆弧刀结合刀具补偿方法对平面调制结构的轮廓精度提升具有显著作用,相比于尖刀切削,圆弧刀补偿加工的一维调制样品获得了更高的表面质量和轮廓精度.针对幅值a=4μm,周期λ=60μm的平面调制样品,采用圆弧刀补偿加工方案,调制样品的表面粗糙度Ra值由59.66 nm降至21 nm,轮廓误差精度提高了约20%.

基于Bayes时空模型分析HIV/AIDS晚发现的时空分布特征及其影响因素

【目的】旨在分析兰州市HIV/AIDS晚发现的时空聚集性特征及相关影响因素,明确兰州市HIV/AIDS晚发现高风险地区和时间趋势,为兰州市因地制宜地制定HIV/AIDS防治策略措施提供参考依据。【方法】选择兰州市2011-2018年间新报告的成年HIV/AIDS病例作为研究对象,研究中所需的数据资料来自兰州市疾病预防控制中心和兰州市统计年鉴。采用Bayes时空模型分析HIV/AIDS晚发现相对风险(RR)的时空分布特征及其影响因素。【结果】2011-2018年间兰州市新报告的HIV/AIDS病例共计1984例,其中HIV/AIDS晚发现者有982例(49.5%),平均年龄为39.67岁,男性占90.9%。老年人和女性HIV/AIDS病例中晚发现的比例更高;城关区(51.1%)、安宁区(50.3%)和榆中县(51.9%)具有高于平均水平的HIV/AIDS晚发现比例;2011-2018年间兰州市总体的晚发现比例呈波动上升趋势。Bayes时空模型分析结果显示,兰州市HIV/AIDS晚发现风险在2011-2015年间波动变化,而在2015年后迅速上升,其RR(95%CI)从1.01(0.84,1.23)上升到1.11(0.77,1.97);红古区和三个县的晚发现风险变化趋势与兰州市的总体变化趋势相似,而城关区和七里河区的晚发现风险呈下降趋势;晚发现相对风险大于1的区县包括:永登县(RR=1.07,95%CI:0.55,1.96)、西固区(RR=1.04,95%CI:0.67,1.49)、城关区(RR=2.41,95%CI:0.85,6.16)和七里河区(RR=2.03,95%CI:1.10,3.27)。冷热点分析结果显示城关区和七里河区为热点区。影响因素分析结果显示,随着人均GDP(RR=0.65,95%CI:0.35,0.90)和HIV/AIDS病例中的男性比例(RR=0.53,95%CI:0.19,0.92)的增高,HIV/AIDS晚发现的相对风险越低;而人口密度(RR=1.35,95%CI:1.01,1.81)越大,晚发现风险越高。【结论】兰州市的HIV/AIDS晚发现风险呈上升趋势,并且存在明显的地区差异特征;人均GDP、HIV/AIDS中男性比例和人口密度是HIV/AIDS晚发现的影响因素。因此,对于晚发现风险高和存在相关风险因素的区县,应重视并制定有针对性的HIV筛查和防治服务,降低HIV/AIDS晚发现比例和风险。

木材变磁铁创新趣味科研技能训练的探索与实践

高校是培养有见识、独立思考能力和创新意识专业人才的摇篮。通过木材变磁铁的科研技能训练课程实验,提升了学生综合运用所学知识开展科学研究的能力。本实验内容不但使学生了解木材的相关知识,而且锻炼了学生独立操作科研仪器和分析谱图的能力,打开了学生在科研领域的新视野,激发了学生热爱学习和科学研究的内在动力。

基于磁性传感器的低失调温度补偿接口电路设计

面向磁性传感器在物联网(IoT)技术中的广泛应用,该文基于180 nm CMOS工艺设计了一种具有低失调电压,低温度漂移特性的霍尔传感器接口电路。针对霍尔传感器灵敏度的温度漂移特性,该文设计了一种感温电路并与查表法相结合,调节可编程增益放大器(PGA)的增益有效地降低了霍尔传感器的温度系数(TC)。在此基础上,通过在信号主通路中使用相关双采样(CDS)技术,极大程度上消除了霍尔传感器的失调电压。仿真结果表明,在–40°C~125°C温度范围内,霍尔传感器的TC从966.4 ppm/°C减小到了58.1 ppm/°C。信号主通路的流片结果表明,霍尔传感器的失调电压从25 mV左右减小到了4 mV左右,霍尔传感器的非线性误差为0.50%。芯片的总面积为0.69 mm^(2)。

投入固定视角下的中国城市节能减排分析

基于最小调整策略的固定投入和DEA模型得到均衡前沿面,提出了节能减排绩效测量模型和综合效率测量模型,对中国城市节能减排效率开展了研究.结果表明,在考虑土地利用的情况下,中国城市的节能减排效率显著降低;中国城市土地供不应求问题逐步得到改善,但土地供需缺口依然较大;五线城市的土地利用效率不高,但是节能减排效率却呈逐年递增;85%的样本城市没能实现土地利用和节能减排的双赢.研究结果为政府在宏观和中观层面制定城市经济可持续发展政策提供了一定的理论和现实依据.

重庆地区油茶低产林高接换种改造成效分析

为解决重庆地区油茶低产林改造投入高、周期长、成效不稳定等问题,以重庆当地引种驯化的6个优良品种为接穗,通过高接换种方式进行品种改造。结果显示:6个优良品种的高换成活率表现最好的是长林18号,长林4号和长林3号次之;接穗基径粗度表现最好的是长林18号,长林3号、长林4号和长林40号次之;枝条长度和树木冠幅生长方面,长林4号表现最好,长林3号次之。产量方面,单株鲜果产量大小依次为长林3号>长林4号>湘林210号>长林53号>长林40号>长林18号。表观质量方面,湘林210号在单果质量、果径和鲜果高度上表现最好,但同时具有果皮最厚的缺点,鲜果出籽率相对不高;长林3号、4号和53号在单果质量、果径和鲜果出籽质量指标上较湘林210号相对略差,但这3个品种果皮薄,鲜果出籽率较高。经AHP层次分析法综合评价,得分高低依次为长林3号(9.359)>长林4号(9.204)>长林53号(8.056)>湘林210号(8.046)>长林40号(7.292)>长林18号(5.506)。重庆油茶低效林高接换种改造品种选择中,优先推荐长林3号和4号,为达到高产效果,可优选长林53号和湘林210号作为配置品种。

上行社会比较对大学生学习内卷的影响:焦虑的中介与自我肯定的调节作用

目的:探讨上行社会比较与大学生学习内卷的关系,并考察焦虑和自我肯定在其中的中介和调节作用。方法:采用上行社会比较量表、焦虑量表、自我肯定问卷和大学生学习内卷问卷对826名在校大学生进行问卷调查。结果:①上行社会比较和大学生学习内卷呈显著的正相关(r=0.22,P<0.01);②焦虑在上行社会比较与大学生学习内卷之间起部分中介作用(β=0.33,P<0.01),中介作用占总效应的13.64%;③自我肯定对中介模型的前半段起显著的调节作用(β=-0.25,P<0.01),当自我肯定水平越高,上行社会比较对焦虑的影响越弱;④自我肯定对直接路径起显著的调节作用(β=-0.07,P<0.05),当自我肯定水平越高,上行社会比较对大学生学习内卷的影响越弱。结论:上行社会比较能显著正向预测大学生学习内卷,焦虑在上行社会比较和大学生学习内卷之间起着部分中介作用,上行社会比较-焦虑-大学生学习内卷这一中介路径的前半段和直接路径受到自我肯定的调节。

稀土转光膜对日光温室小环境、甜瓜生长、果实品质的影响

为稀土转光膜在设施蔬菜生产上的应用提供参考依据,以甜瓜嘉帅红星为试材,以普通高保温PO流滴膜为对照,研究在PO流滴膜基础上添加稀土转光材料母粒的稀土转光膜对日光温室内环境、甜瓜生长、果实品质的影响。采用OHSP-350UVCOHS光谱仪对棚膜透射光谱进行测定,使用SPAD-502型叶绿素计等仪器、HOBO无线蓝牙温光度记录仪、PAL-BXIAACID3系列ATAGO艾拓糖度计等测定棚膜的光学性能及其覆盖日光温室内小环境、甜瓜生长、果实产量和主要品质等指标。结果表明,与普通PO流滴膜相比,添加稀土转光剂的稀土转光膜增加了棚内蓝紫光的比例,降低了绿光、红橙光的比例,降低了稀土转光膜温室内平均光照度和日最高光照度,提升了棚室内平均空气湿度、日最低空气湿度,甜瓜开花、授粉期提前2 d,甜瓜产量提高14.4%,商品瓜率提升2.7%,裂瓜率降低23.5%。综上,与高保温PO流滴膜相比,稀土转光膜在日光温室甜瓜栽培上具有增强植物光合作用、促进植株生长发育的作用。