基于集成SAO优化互相关熵极限学习机模型的变压器故障诊断方法

针对基于传统机器学习的变压器故障诊断方法在数据不平衡、训练数据集存在离群值等条件下稳健性弱和泛化能力不强等问题,提出一种稳健集成学习模型用于实现电力变压器的高精度故障诊断。首先针对离群值对模型稳健性的影响,将互相关熵损失(correntropy loss,CL)引入极限学习机(extreme learning machine,ELM)框架并应用梯度法获得最优解,以构建稳健学习模型CLELM,并利用雪消融优化器(snow ablation optimizer,SAO)优化CLELM的隐含层权重和偏差,以进一步改进其性能。其次,为了增强模型的泛化能力,将多个SAO-CLELM进行加权融合以构成稳健集成学习模型。最后,针对变压器故障数据集不平衡问题,采用合成少数类过采样技术对数据进行扩充,并应用平衡化后的数据训练集成SAO-CLELM模型以实现故障诊断。在两种故障测试集下对所提集成SAO-CLELM模型的故障诊断性能进行了验证,实验结果表明所提模型能获得准确的故障分类结果,说明其具有较高的稳健性和泛化性。

2024年2月我国两次雨雪冰冻过程中闪电活动特征对比分析

2024年1月31日-2月5日和2月18-25日(以下分别简称为"0131"和0218"过程)我国南方遭遇两次雨雪冰冻天气,并伴随密集的闪电发生。利用三维闪电定位数据、CLDAS-V2.0降水产品和Himawari-9号卫星红外云图资料,对比分析两次雨雪冰冻天气背景下的地闪时空分布、地闪回击数和雷电流累计概率分布特征,并研究了地闪与降水量及卫星黑体辐射亮温(TBB)间的关系。结果表明:(1)两次过程中共监测到地闪数13万余次,正、负地闪分别为2万和11万余次;两次过程的地闪均具有夜发性,正地闪较总地闪和负地闪峰值滞后约1~2h。两次过程中正地闪产生大电流的概率大于负地闪。(2)"0131"过程中地闪密度大值区出现在贵州南部及贵州、重庆、湖北三省交界处;"0218"过程中地闪密度大值区出现在湖北东部、江西北部、安徽、江苏和浙江大部。(3)"0131"过程中降水量和地闪的时空分布不一致,降水量峰值集中在白天,降水集中在湖南东南部、江西、安徽和江苏南部、浙江和福建大部;而"0218"过程中降水量和地闪的时空分布较一致,地闪出现的峰值较降水量峰值延迟2h。(4)两次过程中地闪的分布均很好地指示了对流区。地闪主要分布在对流云团发展方向的尾部且偏南处TBB变化梯度大的区域;对流合并会导致合并处地闪频数的跃增;对流发展最旺盛的冷云核心区几乎没有地闪发生。两次过程地闪密度随着TBB的增大呈现先增大后减小的变化特征。

受致灾气旋影响的不同规模等级城市直接经济损失特征

本文将造成直接经济损失的热带气旋定义为致灾气旋。依据城区常住人口,将我国城市划分为小城市、中等城市、大城市三种规模等级,基于1984—2019年热带气旋灾情和路径数据筛选出致灾气旋,分析我国城市的致灾气旋频次、强度,并研究致灾气旋造成的不同规模城市直接经济损失变化。主要结论为:(1)1984—2019年影响我国城市的致灾气旋为7.7个·a^(-1),呈微弱下降趋势,而强台风和超强台风的发生频次呈显著增加趋势(α=0.05显著水平),30°N以南城市频次整体比北部高;(2)由于致灾气旋影响范围增加,暴露于不同强度致灾气旋的城市个数呈增加趋势,其中暴露于强台风的城市个数增速最快,约为2.0个/(10 a);致灾气旋影响城市个数增加以及城市经济快速发展,使得暴露于致灾气旋影响范围内的经济总量迅速增加,以大城市经济暴露度(占比81.7%)的增速最快(402.6亿元·a^(-1));(3)1984—2019年致灾气旋造成的城市直接经济损失约为262.3亿元·a^(-1)(以2019年市值),呈增加趋势;城市经济快速发展和高强度致灾气旋频次增加的共同作用下,城市经济损失占我国致灾气旋经济损失的比重从30.0%增加到63.3%。大城市资产财富集中,且多位于沿海地区,致灾气旋发生频次较多,经济损失占比最大(为51.4%),增速最快(为5.2亿元·a^(-1))。

ChatGPT支持下的震例分析报告生成方法研究

生成式大语言模型目前已成为人工智能在自然语言处理领域的研究热点,它可以帮助人类从繁重的工作和重复劳动中解放出来。以ChatGPT为例,探讨生成式大语言模型在震例分析中的应用,降低地震科研工作者的劳动强度,提高工作效率。实验发现,在设定的聊天情景下,ChatGPT可以理解输入的自然语言内容,生成与之相符的答复结果;通过不断地与ChatGPT进行地震领域的知识交流,借助ChatGPT出色的前后学习机制,向ChatGPT输入以往震例分析报告的语言风格和报告模板,使得ChatGPT能够学习地震知识,生成与当前震例报告风格一致的震例分析报告;通过对比不同报告模板生成的分析报告内容,人工剔除报告中的错误信息,选择优质的震例分析报告,从而提高了报告的实用价值。这拓宽了ChatGPT的应用领域,为地震工作者提供了更加便利的服务。

深圳市居民使用药品说明书情况及其影响因素研究

目的探究深圳市居民说明书使用情况,为相关部门完善药品说明书及药品知识宣传等方面提供参考依据。方法采用非概率抽样方法,由深圳市社区服务中心义工上门服务时,依托问卷星平台对居民使用药品说明书情况进行问卷调查。采用SPSS 25.0软件对收集到的数据进行χ^(2)检验和Logistic回归分析。结果问卷共回收1592份,最终有效问卷为1566份,有效回收率为98.36%;用药前阅读药品说明书的占75.61%;因对说明书的理解偏差导致不安全用药的占22.92%;53.63%的居民在阅读说明书时遇到字体太小,或间距太小,不方便阅读等问题;57.34%的居民希望说明书以纸质版和电子版两种形式呈现;用药前阅读说明书受性别、文化程度以及从事/学习医药专业影响(χ^(2)=14.779、29.895、56.526,P<0.05)。Logistic分析显示,居民存在不安全用药行为与性别、年龄、从事/学习医药专业工作以及阅读药品说明书有关,OR值分别为0.338(95%CI:0.255-0.449)、0.324(95%CI:0.162-0.648)、0.140(95%CI:0.076-0.259)、0.436(0.280-0.679)。结论居民药品说明书使用率较高,其主要受性别、文化程度以及从事专业的影响;居民因不能正确或有效使用药品说明书导致不安全用药等仍有风险;仍需做好药品说明书相关知识宣传,正确地指导居民用药。

食品安全风险监测信息平台设计

详细阐述食品安全风险监测信息平台系统设计,包括业务框架、应用系统、标准规范体系、数据采集和交换方式、基于大数据的食源性疾病预警等方面,指出该平台建设有助于提高国家、省两级平台数据采集交换能力,推进各地食品安全信息化建设,完善国家食品安全风险监测管理工作流程。

超短焦投影镜头曲面反光杯智能调校装置设计

曲面反光杯的调校直接影响超短焦投影的投射比、视场、图像质量等关键参数。针对人工调校效率低、联动性差、性能不稳定等问题,设计了一种新型的智能调校装置,制作了原理样机并进行了实验测试。装置由三轴移动平台及调校螺丝刀组成,其中三轴移动平台采用滚珠丝杆直线模组搭建,定位精度高,可让调校螺丝刀沿X,Y,Z三个方向运动,以适用于不同安装位置的曲面反光杯;螺丝刀头部凹槽设计成外圆内方结构,通过3D打印成型,由伺服电机驱动,能与反光杯调校螺母自动对中。样机测试结果表明,装置运行稳定、联动性好、可根据投影图像畸变信息,60 s内自动完成调校过程,相比人工调校,效率至少提高了50%。

耦合全息光栅转换平行光的研究及其应用

从理论和实验上研究了用一对全息光学(HOE)获得输出光束相同于输入平行光束的可行性。讨论了这种耦合HOE的应用性。

重庆主城区高血压病人降血压膳食知信行现况研究

目的了解重庆主城区高血压病人降血压膳食(DASH)相关知识、态度、行为(KAP)现状,为开展高血压病人DASH健康教育提供依据。方法随机抽取2个主城区,再从每个区中随机抽取1个社区卫生服务站作为调查点,采用自行设计的DASH相关KAP问卷对2016年4-6月来调查点就诊、咨询的445名高血压病人进行面对面问卷调查,并对所得结果进行统计分析。结果高血压病人DASH相关KAP问卷的知识、态度、行为部分平均得分分别为(3.5±1.9)分,(6.0±0.9)分及(5.1±1.4)分。高血压病人对DASH推荐水果、奶类摄入量的知晓率较低,分别为3.4%和3.1%。64.1%的高血压病人赞同/非常赞同"健康饮食可以控制血压",而24.7%的高血压病人对"高血压不碍事"持无所谓态度。此外,水果、奶类、坚果的摄入量达到DASH推荐摄入量的高血压病人比例分别为1.6%,1.6%及2.5%。Spearman相关分析结果显示,高血压病人的DASH知识、态度及行为之间均呈正相关(P<0.01)。同时不同吸烟情况的高血压病人其DASH知识、态度、行为得分的差异均有统计学意义(F=3.618,22.276,11.456;P<0.05);不同血压监测频率的高血压病人其DASH知识、态度、行为得分的差异均有统计学意义(F=13.106,7.053,6.695;P<0.05);不同体质量监测频率的高血压病人其DASH知识、态度、行为的得分差异均有统计学意义(F=7.377,6.395,6.010;P<0.05)。结论重庆主城区高血压病人DASH知识水平较低,存在诸多不健康的饮食行为,但态度较积极,因此,有必要加强针对主城区高血压病人的DASH健康教育,提高其知识水平,进而促进其不健康饮食行为的改善。

北京大学生个体臭氧暴露直接测量及潜在健康风险评估

为探究个体臭氧暴露量与臭氧环境监测值之间的关系,准确评估北京市臭氧污染的健康风险,本工作利用小型臭氧测量仪,直接测量在校大学生的个体臭氧暴露浓度,获取了北京地区特定群体个体平均臭氧暴露浓度与环境中臭氧监测值之间的定量关系。根据臭氧暴露浓度与人体健康效应关系模型,对北京地区2018-2020年大学生群体的臭氧污染健康风险进行了评估。结果表明,大学生群体日间个体暴露率为39±1%。取《环境空气质量标准》(GB3095—2012)中规定的臭氧浓度一级标准限值(100μg/m^(3))作为健康风险评估的参考浓度,则大学生群体归因臭氧污染过早死亡人数在2018、2019和2020年分别为14人、20人和23人。暴露率增加20%,臭氧健康风险约增加2~3倍;暴露率增加50%,臭氧健康风险约增加6~8倍。参考浓度取较低阈值26.7ppb时,评估得到的健康风险约升高了两倍。在一天24h内,下午13时到17时臭氧造成的健康危害最大,在一年四季中,夏季臭氧造成的健康危害最大,这与大气臭氧浓度变化规律相一致。在臭氧污染严重的天气,应尽量减少室外活动或者采取防护措施,以降低臭氧暴露带来的健康风险。

Evaluation of Isoflavones as Allelochemicals with Strong Allelopathic Activities of Kudzu Using Protoplast Co-Culture Method with Digital Image Analysis

The inhibitory allelopathic activity of Pueraria montana (Kudzu), and activities of two putative allelochemical isoflavones, puerarin and daidzein, were evaluated using the protoplast co-culture method with digital image analysis using lettuce as a recipient (DIA-PP method). Cotyledon protoplasts of Kudzu were isolated using Cellulase R10 and Driselase 20 in 0.6 M mannitol solution. Optimal hormonal condition and density for growth of Kudzu protoplasts were surveyed. Medium for co-culture of Kudzu or isoflavones with lettuce protoplasts was 50 μl liquid MS basal medium containing 1 μM 2,4-dichlorophenoxyacetic acid, 0.1 μM benzyladenine, 3% sucrose, and 0.4 M or 0.6 M mannitol. Protoplast division of lettuce was strongly inhibited by Kudzu at a low density (104/ml). Slightly less inhibition by Kudzu on cell wall formation and yellow pigment accumulation stages of lettuce growth was also observed. Puerarin did not inhibit the growth of lettuce protoplasts at three growth stages but slightly stimulated growth at high concentrations. By contrast, daidzein, aglycon of puerarin, inhibited growth at three stages of lettuce protoplast growth and strongly inhibited cell division at 100 μM. Daidzein might be one cause of the strong inhibitory allelopathic activity of Kudzu. Grade of inhibitory activities was compared with that of other allelopathic plants including an invader plant and their allelochemicals studied using the DIA-PP method.

高效液相色谱测定番茄中茚虫威残留及消解动态

为探明茚虫威在番茄中的残留特性和安全性,采用高效液相色谱技术测定茚虫威在番茄上的残留及消解动态。样品经甲醇提取和二氯甲烷萃取后,采用高效液相色谱技术检测,外标法定量。结果表明:在0.0051.0μg/mL范围内,茚虫威质量浓度与其峰面积间呈良好的线性关系,R2为0.9998;在0.05、0.2、1.0 mg/kg的3个加标水平下,茚虫威的回收率为82.5%102.4%,相对标准偏差(RSD)为2.2%4.3%;消解动态回归方程为y=0.1154e-0.259x,R2为0.9949,半衰期为2.7 d;15%安打悬浮剂按666.7m220 mL和30 mL两个施药量对水喷雾,施药后10 d茚虫威残留量均低于0.01 mg/kg。本研究结果可为茚虫威在番茄上的合理使用及其最大残留限量制定提供参考。

Biological performance of particleboard incorporated with boron minerals

We compared resistance to decay, mold fungi, termites and insect larvae of particleboards incorporated with the raw boron minerals ulexite and colemanite to that of particleboards impregnated with the commercial boron preservative zinc borate, or boric acid plus a borax mixture. We also quantified water absorption, thickness swell and boron release of particleboards. Ulexite had the best decay resistance, and colemanite had the best termite resistance. However, ulexite and colemanite were not as effective as zinc borate or the boric acid/borax mixture in preventing mold growth. In general, the boric acid/borax mixture combination was more effective against Anobium larvae than the other treatments. Less boron was released by specimens containing zinc borate and colemanite than by those containing ulexite or the boric acid/borax mixture. In general, water absorption and thickness swell were similar among the different treatments, but both were slightly higher in the ulexite-incorporated specimens. Further mechanical tests will be needed to evaluate the particle- board properties and thereby the compatibility of these boron minerals with various manufacturing processes.

Biological performance,water absorption,and swelling of wood treated with nano-particles combined with the application of Paraloid B72~

We evaluated fungal decay and mold resistance,leaching, and water absorption of nano-compounds and Paraloid B72-（PB72） in treated wood specimens to develop new methods of consolidation by combining nanoparticles and consolidants. Scots pine wood specimens were treated with dispersions of nano-Cu O, nano-Zn O,nano-B2O3, nano-Ti O2, and nano-Ce O2. PB72 treatments of nano-particle-treated wood specimens were then carried out by either vacuum or immersion for 24 h. Previously,decayed wood specimens were also consolidated with the nano-compounds and PB72. PB72 treatments reduced element release from treated wood specimens. Nearly all nano-compounds ？ PB72 treatments increased the biological performance of treated wood specimens against decay fungi tested. PB72-only treated wood specimens had the highest weight losses in decay tests. No improvements were obtained in mold resistance tests when the nanocompounds and PB72 were combined. In nano-compoundonly treatments, unleached specimens showed slightly lower water absorption values compared to untreated control specimens. Incorporation of PB72 into nano-compound-treated wood specimens resulted in considerably lower water absorption and volumetric swell. In previously decayed specimens treated with the nano-compounds and PB72 solution, water absorption after 2-h immersion declined compared to control specimens.

鼓槌石斛和流苏石斛化学成分及药理活性的研究进展

目的:对鼓槌石斛和流苏石斛的化学成分、生物活性的研究进展进行综述,为深入研究和开发提供科学依据。方法:系统检索国内外研究资料和相关报道,进行整理和分析。结果:按照结构类型,鼓槌石斛和流苏石斛的化学成分可分为联苄及其衍生物类、菲类及其糖苷类、苯丙素及其衍生物类、芴酮类、小分子酚酸类、醌类、甾体类等。生物活性研究表明:其具有改善眼部疾病、抗肿瘤、抗氧化、增强免疫力、胃粘膜保护、抗血栓、肝保护等活性。结论:鼓槌石斛和流苏石斛在药物和保健食品开发方面具有较好的应用前景。

Effects of salinity on the nail-holding power of dimension lumber used in light-frame wood building

We studied the effect of salinity on nail-hold- ing power in wood construction. In saline solution, the holding power of nails was less than in purified water. With the increase of salt concentration, the surface and side nail- holding power of the wood specimens both declined, but the differences between salinity treatments were not sig- nificant. However, compared to the surface and side nail- holding power, the power on the edge was generally less and the difference was not obvious in different salt con- centrations. In the same salt concentration, with the extension of the processing cycle, the performance of holding power of nails showed a downward trend, expect the temporary rise in the middle.

High-Power Simultaneous Wireless Information and Power Transfer: Injection-Locked Magnetron Technology

Applications using simultaneous wireless information and power transfer(SWIPT)have increased significantly.Wireless communication technologies can be combined with the Internet of Things to develop many innovative applications using SWIPT,which is mainly based on wireless energy harvesting from electromagnetic waves used in communications.Wireless power transfer that uses magnetrons has been developed for communication technologies.Injection-locked magnetrons that can be used to facilitate high-power SWIPT for several devices are reviewed in this paper.This new technology is expected to pave the way for promoting the application of SWIPT in a wide range of fields.

Evaluation of Screw Reinforcement on Bearing Performance of Wood Depending on Screw Position

In this study, the reinforcement of wood by screws for partial compression perpendicular to the grain was studied. For the estimation of stiffness and strength, the reinforcement effect of screws depending on their position under the loading plate was evaluated by taking into account the internal displacement distribution of the wood. The finite element analysis (FEA) was used to investigate the internal displacement distribution of the wood. Then an approximate function that can be applied to various internal displacement distributions under loading plate was proposed. From the shear resistance mechanism between the screw and wood by taking their relative displacement distribution into consideration, the equations to estimate the initial stiffness and yield strength of the bearing performance of the wood reinforced by screws were derived. Then partial compression test was carried out for wood reinforced by screws with setting screw thread at various positions. The values obtained by the equations corresponded with the tendency of the experimental results. It was found that the screw reinforcement is more effective when its thread is positioned as much as distant from the contact surface.

论国有企业大兴调查研究的四大关系--基于利益相关者视角

在全党大兴调查研究和新一轮国企改革深化提升行动的背景下,文章聚焦利益相关者视角,深入剖析了国有企业与主要利益相关者的四大关系,包括企业与政府的上下关系、企业与员工的组成关系、企业与企业的左右关系、企业和客户的里外关系。文章指出,国有企业应运用调查研究这个“传家宝”,理顺国有企业在经营中与主要利益相关者之间的关系,正确地发现、认识并处理好自身与主要利益相关者之间的矛盾。同时,文章提出以三大视角审视四大关系、统一主体目标、遵循辩证唯物主义认识论、坚持发展眼光等四方面的政策性建议,以期强化国有企业四大企业关系的管理,为国有企业建立更加科学、更符合当前经济形势的现代公司治理模式提供重要的理论参考和实践价值,进而推动新一轮国企改革的深化和落实。

基于随机有限断层法的泸定6.8级地震强地面运动场重建

基于随机有限断层法开展泸定6.8级地震强地震动模拟,并通过实际强震记录校核,重建了泸定地震的强地面运动场。结果表明:(1)震中距80km以内,大部分模拟峰值地面加速度值与实际值较为接近,峰值地面加速度差值最小为0.58gal;(2)与低频段相比,高频段加速度反应谱的模拟效果较好,与实际反应谱的吻合度更高;(3)模拟峰值地面加速度(PGA)、峰值地面速度(PGV)、谱烈度(SI)及仪器地震烈度(II)的最大值分别为433gal、30cm/s、34cm/s、8.5,除II的模拟结果未展现Ⅸ度区外,各地震动参数均沿断层延伸方向呈对称分布,且在宏观形态上与地震烈度图的相似性较强;(4)与实际地震烈度图相比,重建的强地面运动场可有效预估地震烈度Ⅶ~Ⅸ度区的分布范围。作为合理确定地震动输入的一种途径,研究结果不仅可为泸定地区的抗震设防工作提供技术支撑,也可为特定地震强地震动(高频)的快速模拟提供参考。