光伏直流配电故障诊断及火灾风险评估技术

长期服役的光伏发电系统直流配电故障概率高、火灾风险及危害大,严重影响光伏电站的运行安全、发电与出力能力,并对电站运维提出故障与火灾精准检测的技术挑战。为此,从生产现场直流配电柜故障分析入手,揭示接触不良、绝缘劣化、故障电弧、电气火灾的演变机理;分析国内外故障电弧诊断与火灾检测技术的理论成果应对在运电站电弧火灾的有效性,提出故障电弧预诊断与火灾检测技术的应用解决方案。研究结果表明,提出的故障电弧诊断与火灾检测技术应用方案,弥补直流继电保护对串联电弧故障无法保护的不足,能够有效诊断故障电弧并检测烟雾和高温,避免火灾及其扩大事故的发生。

电厂脱硫产物中痕量元素形态及毒性浸出特性

燃煤电厂副产物脱硫石膏和污泥在雨水中或作为固体废弃物加工过程中,吸附的痕量元素会再次进入环境中,造成二次污染。选取安徽省3个典型燃煤电厂超低排放机组,通过欧洲共同体标准物质局(BCR)逐级提取法测定脱硫污泥和石膏中Cr、As、Cd和Pb的赋存形态,应用标准毒性浸出程序法(TCLP)对脱硫石膏的浸出毒性进行测定,分析脱硫副产物中Cr、As、Cd和Pb的潜在环境影响。结果表明:脱硫污泥中4种元素的质量浓度明显高于脱硫石膏;脱硫石膏中Cr和As稳定性高,Cd和Pb元素有效态占比大于50%,迁移能力强,对生态环境具有潜在的风险;脱硫污泥中Cr、Cd和As的迁移能力较强,环境风险较高,其中Cr在氧化环境中不稳定,Cd在酸性环境中更易浸出,As在氧化和还原环境中均不稳定;pH和固液比对石膏中重金属浸出有重要影响,不同元素之间存在较大差异;Pb、Cr和As浸出率随着pH的降低而增大,随液固比的增大而增大,并逐渐达到平衡;Cd的最大浸出率低于其他3种元素,浸出率与pH和固液比的相关性较弱,在pH为4.47时,浸出率较高。研究结果可为燃煤电厂脱硫副产物处置及再利用提供参考。

安徽省部分地区硬蜱蜱种鉴定及蜱携带无形体检测

目的了解安徽省部分地区硬蜱蜱种种类、蜱种分布及蜱虫携带无形体情况,为蜱传无形体防控提供参考依据。方法于2023年4月至8月,在安徽省金寨县、含山县、旌德县、巢湖市等地通过布旗法和从动物身上采集硬蜱共计630只。用体式显微镜进行形态学鉴定,设计蜱特异性引物进行蜱种分子生物学鉴定。设计无形体16S rRNA特异性引物用巢式PCR检测单只蜱虫无形体携带情况。利用MEGA11.0构建系统发育树并分析。结果安徽省金寨县微小扇头蜱占18.8%(18/96)、长角血蜱占81.2%(78/96),含山县、巢湖市均为长角血蜱,旌德县均为微小扇头蜱。长角血蜱携带无形体阳性率为30.9%(102/330),包括牛无形体1.8%(6/330)、嗜吞噬细胞无形体21.8%(72/330)和一种uncultured无形体7.3%(24/330),微小扇头蜱携带嗜吞噬细胞无形体13.6%(18/132)。牛无形体和未培养无形体在游离蜱检测出,在24.4%的寄生蜱和15.8%的游离蜱检测出嗜吞噬细胞无形体。结论安徽省调查县的蜱种包括长角血蜱和微小扇头蜱,长角血蜱和微小扇头蜱及其游离蜱和寄生蜱均携带无形体。

Establishment of a system for screening and identification of novel bactericide targets in the plant pathogenic bacterium Xanthomonas oryzae pv. oryzae using Tn-seq and SPR

Xanthomonas spp. cause severe bacterial diseases. However, effective strategies for prevention and management of these diseases are scarce. Thus, it is necessary to improve the efficiency of control of diseases caused by Xanthomonas. In this study, Xanthomonas oryzae pv. oryzae(Xoo), which causes rice bacterial leaf blight, has been studied as a representative. A transposon insertion library of Xoo, comprising approximately 200,000 individual insertion mutants, was generated. Transposon sequencing data indicated that the mariner C9 transposase mapped at 35.7–36.4% of all potential insertion sites, revealing 491 essential genes required for the growth of Xoo in rich media. The results show that, compared to the functions of essential genes of other bacteria, the functions of some essential genes of Xoo are unknown, 25 genes might be dangerous for the Xanthomonas group, and 3 are specific to Xanthomonas. High-priority candidates for developing broad-spectrum, Xanthomonas-specific, and environment-friendly bactericides were identified in this study. In addition, this study revealed the possible targets of dioctyldiethylenetriamine using surface plasmon resonance(SPR) in combination with high performance liquid chromatography–mass spectrometry(HPLC–MS). The study also provided references for the research of some certain bactericides with unknown anti-bacterial mode of action. In conclusion, this study urged a better understanding of Xanthomonas,provided meaningful data for the management of bacterial leaf blight, and disclosed selected targets of a novel bactericide.

Study on concentration distribution and detonation characteristics for non-axisymmetric fuel dispersal

The study of non-axisymmetric fuel dispersal and detonation can provide reference for the prevention of industrial cloud explosion accidents and the design of fuel air explosive(FAE).The concentration and detonation fields of 85 kg cylindrical and fan-shaped fuel are investigated by experiments and numerical simulations.A dynamic model of the whole process for fuel dispersal and detonation is built.The concentration distribution of fuel is used as the initial condition to calculate the detonation stage,thus solving the initial value problem of detonation field.The phase and component changes of fuel cloud at different locations are compared.The fuel cloud is divided into directions of 0°,90°,135°and 180°.The results show that the maximum cloud radius is 20.94 m in 135°and the minimum is 12.04 m in 0°.The diameter of the detonation fireball is 53.6 m,and the peak temperature is 3455 K.The highest peak overpressure is 3.44 MPa in 0°and the lowest is 2.97 MPa in 135°.The proportion of liquid phase in 0°is22.90%,and the fuel loss is 11.8% and 9% higher than that in 135°and cylindrical charge,respectively.The stable propagation distance of blast wave in 135°is 42.50% longer than 0°and 28.37% longer than cylindrical charge.

BaTiO_(3)/p-GaN/Au self-driven UV photodetector with bipolar photocurrent controlled by ferroelectric polarization

Ferroelectric materials are promising candidates for ultraviolet photodetectors due to their ferroelectric effect.In this work,a BaTiO_(3)/p-GaN/Au hybrid heterojunction-Schottky self-driven ultraviolet photodetector was fabricated with excellent bipolar photoresponse property.At 0 V bias,the direction of the photocurrent can be switched by flipping the depolarization field of BaTiO_(3),which allows the performance of photodetectors to be controlled by the ferroelectric effect.Meanwhile,a relatively large responsivity and a fast response speed can be also observed.In particular,when the depolarization field of BaTiO_(3) is in the same direction of the built-in electric field of the Au/p-GaN Schottky junction(up polarized state),the photodetector exhibits a high responsivity of 18 mA/W at 360 nm,and a fast response speed of<40 ms at 0 V.These findings pave a new way for the preparation of high-performance photodetectors with bipolar photocurrents.

Research on the influences of motion characteristics of jetting projectile charge under water

Shaped charge warhead is important for enhancing the damage performance of underwater weapons.This paper used finite element analysis software and based on JPC water penetration experiments to examine the influence of liner parameters(wall thickness,material),charge aspect ratio,and stand-off distance on the movement characteristics of JPC in water.The findings reveal that the head diameter of the JPC increases and experiences significant erosion after entering the water,the effective length of the JPC in water undergoes two distinct phases:a growth phase and a decrease phase,with the velocity of the JPC decaying exponentially.Increasing the liner thickness,stand-off distance and the charge aspect ratio can improve the erosion resistance and the velocity retention capacity of the JPC.The optimal ranges for liner thickness and stand-off distance are 0.0363D_(k) to 0.0545D_(k)(D_(k) is the charge diameter),the stand-off distance should be within 1.0D_(k).After the charge aspect ratio higher than 1.25,the charge structure exerts minimal influence the movement characteristics of the JPC in water.Material density plays a crucial role in the velocity decay pattern of the JPC during penetration.JPC with higher densities exhibit superior velocity retention capabilities in water,with the velocity decay pattern converging if the densities are similar.Consequently,copper,tantalum and tungsten liners are deemed appropriate for underwater shaped charge warhead.Finally,the results will provide an important reference for the design of underwater shaped charge warhead.

Investigation on taste characteristics and sensory perception of soft-boiled chicken during oral processing based on electronic tongue and electronic nose

The sensory perception of food is a dynamic process,which is closely related to the release of flavor substances during oral processing.It’s not only affected by the food material,but also subjected to the individual oral environment.To explore the oral processing characteristics of soft-boiled chicken,the sensory properties,texture,particle size,viscosity,characteristic values of electronic nose and tongue of different chicken samples were investigated.The correlation analysis showed that the physical characteristics especially the cohesiveness,springiness,resilience of the sample determined oral processing behavior.The addition of chicken skin played a role in lubrication during oral processing.The particle size of the bolus was heightened at the early stage,and the fluidity was enhanced in the end,which reduced the chewing time to the swallowing point and raised the aromatic compounds signal of electronic nose.But the effect of chicken skin on chicken thigh with relatively high fat content,was opposite in electronic nose,which had a certain masking effect on the perception of umami and sweet taste.In conclusion,fat played a critical role in chicken oral processing and chicken thigh had obvious advantages in comprehensive evaluation of soft-boiled chicken,which was more popular among people.

度洛西汀联合拉莫三嗪治疗抑郁症的临床效果

目的探究度洛西汀联合拉莫三嗪治疗抑郁症的临床效果。方法选取2022年1月—2023年1月收治的抑郁症95例,采用随机数字表法随机将其分为对照组(47例)、研究组(48例)。对照组给予度洛西汀治疗,研究组给予度洛西汀联合拉莫三嗪治疗,均持续治疗3个月。比较2组治疗效果、单胺类神经递质[多巴胺(DA)、去甲肾上腺素、5-羟色胺(5-HT)]、内分泌激素[促肾上腺皮质激素、皮质醇(CS)、促肾上腺皮质激素释放激素(CRH)]、抑郁症状[抑郁自评量表(SDS)、汉密尔顿抑郁量表(HAMD)]、认知功能[蒙特利尔认知评估量表(MoCA)]及不良反应。结果研究组临床总有效率91.67%(44/48)高于对照组74.47%(35/47)(P<0.05);治疗1、3个月后,与对照组比较,研究组血清5-HT、CRH水平升高,血清DA、CS水平降低(P<0.05)。治疗1、3个月后,研究组SDS、HAMD评分低于对照组,MoCA评分高于对照组(P<0.05)。2组治疗期间不良反应发生率比较差异无统计学意义(P>0.05)。结论度洛西汀联合拉莫三嗪治疗抑郁症能显著增强临床效果,且具有一定安全性。

基于现实的浪漫——城市山水画的渊源

城市山水画自古以来便已存在。它们或隐寓在画面中,或归入其他题材,直到20世纪80年代钱学森提出“山水城市”概念,城市山水画才被正式别出。中国城市山水画开端于宋代郭忠恕;中华人民共和国成立以后,渐蔚大观。在此基础上,可以给城市山水画予以定义。城市山水画的发展是一种基于现实的浪漫。

重症肌无力生活质量研究的现状和热点分析——基于Web of Science数据库的文献计量学分析

目的了解重症肌无力生活质量(myasthenia gravis-quality of life,MG-QOL)研究的现状和热点。方法检索Web of Science核心合集数据库,分析1985年(建库)至2022-4-26收录的有关MG-QOL研究文献,运用文献计量学分析方法,采用VOSviewer和CiteSpace软件对发文的国家、机构、作者、期刊分布、文献共被引及聚类进行可视化分析。结果共检索到320篇文献,由来自49个国家、625个研究机构的1387位作者发表于165种期刊。美国、意大利、德国的文献发表量最高。弗吉尼亚大学、多伦多医院、综合花卷医院发文量位居研究机构的前3位。刊载量最大的期刊为Muscle&Nerve。Burns TM、Sanders DB二位学者学术影响力、权威性最高。体育锻炼、特异性自身抗体、难治性重症肌无力已成为MG-QOL研究的前沿和热点。结论QOL是MG研究的重要组成部分,对诊疗的有效性评价作用日益增强,越来越多的研究纳入了更广泛的贴近于现实生活的影响因素。

新型冠状病毒感染相关嗅觉障碍的流行现状、机制和康复

新型冠状病毒感染(coronavirus disease 2019,COVID-19),下简称“新冠”,是由严重急性呼吸综合征冠状病毒2(severe acute respiratory syndrome coronavirus 2,SARS-CoV-2)引发的全球流行传染病。鉴于嗅觉障碍是其主要神经症状,明确相关流行现状、机制和康复对促进公共健康非常重要。文献报道的新冠相关嗅觉障碍的发生率存在差异,与评估工具、人群以及变异毒株3个因素有关。其中,不同毒株之间嗅觉障碍发生率的差异可能源于刺突糖蛋白和侵入方式的变异。在外周嗅觉系统,SARS-CoV-2主要引发嗅裂炎症、支持细胞死亡和宿主免疫反应,而关于SARS-CoV-2入侵中枢的途径和机制仍存争议。部分“长新冠”患者存在持续的嗅觉障碍,SARS-CoV-2诱发慢性炎症反应和对嗅上皮再生的破坏是其潜在的病理基础。根据嗅觉媒介假说,SARS-CoV-2可能借由嗅觉系统影响中枢功能并最终诱发神经退行性变。嗅觉训练、药物等方法可帮助新冠相关嗅觉障碍的康复。

燃煤电厂细颗粒物中微量元素排放影响研究

燃煤电厂排放颗粒物中的各种微量元素引起公众的广泛关注。为探究燃煤电厂排放颗粒物中微量元素含量及主要环保设备对元素排放的影响,通过现场试验、文献调研、理化分析等方法,对安徽省一台600 MW超低排放、超临界机组湿法脱硫装置(WFGD)和湿式电除尘装置(WESP)排放细颗粒物中Cr、As、Se、Cd、Pb、Hg元素分布及排放特征进行综合研究。结果表明:燃煤机组排放PM_1、PM_(1~2.5)和PM_(2.5~10)的细颗粒物浓度分别为0.85、0.18和0.02 mg/m~3,WFGD对PM_(2.5~10)的脱除效率达到95%以上,WESP对粒径小于2.5μm细颗粒物的去除效率优于WFGD。WFGD入口处PM_(10)中Cr、As、Se、Cd、Pb、Hg的质量浓度分别为22.8、0.2、28.9、27.7、7.3、2.4μg/m~3,各元素质量浓度在不同分级颗粒物中的分布规律均呈现随着粒径增大而降低的趋势。颗粒物在经过WFGD后,Se元素质量浓度下降70%,Cr元素质量浓度增加466%,Hg和Pb元素质量浓度增长325%和205%,Cd和As增长101%和113%,微量元素主要富集在细颗粒物中。WESP出口处PM_(10)中Cr、As、Se、Cd、Pb、Hg的质量浓度分别为8.3、0.2、8.9、8.2、3.5、1.0μg/m~3,颗粒物中有害微量元素呈下降趋势,其中Se元素质量浓度变化较小,其他5种元素质量浓度均下降约50%。

麻纤维/可降解聚合物复合材料研究进展

随着化石资源的枯竭和传统塑料使用带来的环境问题日益严重,可生物降解的聚合物材料越来越受到人们的关注。目前可降解聚合物的力学性能与传统塑料相比仍然存在一定差距,限制了其应用与发展。将麻纤维加入到可降解聚合物中可以降低复合材料的脆性,提高材料的强度及热稳定性,增强阻隔性能。本文综述了近年来基于不同麻纤维/可降解聚合物复合材料的制备方法、应用和性能增强机理研究,同时指出了目前研究中存在的问题和未来的研究发展方向。

层级孔喷涂粉末构筑及新一代长寿命热障涂层材料的研究进展

广泛应用于航空发动机和地面燃气轮机中的热障涂层具有低热导率和良好的耐温性能,能够降低涡轮叶片表面温度,使高温结构件能在高于其熔点的环境中长时间高效率的服役。热障涂层的性能和寿命受到陶瓷层材料与其结构的直接影响,采用可控原料粉末对陶瓷涂层进行微观结构调节的方法可以减少涂层中的应变-应力失配,具有操作灵活、效果显著、调控范围广等优势。针对传统热障涂层应变容限低,抗热震性能不足等问题,本团队开发了静电喷雾技术结合相分离原理(ESP)制备新型热喷涂微球粉末的造粒理论和实现方法,实现了对粉末形貌结构的精确构筑,可用于制备核壳、均质和层级孔等全体系喷涂微球粉末。与传统的喷涂粉末相比,其中层级孔微球粉末(由特殊的纳米-微米层级跨尺度孔构成)呈现耐烧结、低热导率、高比强度及95%以上的高温波段反射率特点。使用层级孔微球粉末喷涂的热障涂层由于层级孔特征结构的保留,展现出优异的力学性能和隔热性能,热循环寿命提升2倍以上,热导率下降50%以上,且在服役过程中体现出良好的抗烧结性能。ESP造粒技术为新型热障涂层材料从材料设计到工程应用提供了一种快速的涂层性能调控方法,现已成功应用于稀土锆酸盐、稀土钽酸盐和稀土掺杂YSZ高熵体系等新型热障涂层的制备之中,随着层级孔结构对材料力学、光学、热学的深入研究及其内部拓扑结构的精确控制,未来将会在航空航天、军事国防、荧光测温等领域获得更为广泛的应用。

一种SAR回波历程快速实时计算方法

针对合成孔径雷达(Synthetic Aperture Radar,SAR)目标回波模拟计算量过大的问题,采用两次多阶泰勒级数展开对回波系统函数中的距离历程进行计算,并结合数据外推的方法完成距离历程的快速实时计算。该方法使用多次乘法和加法代替计算量较大的开方运算,可保证在一定计算精度的前提下提高距离计算的实时性,同时结合距离历程模型的规律性,采用数据外推代替重复的计算过程,进一步降低计算量,提高实时性。通过仿真对比不同阶数泰勒级数展开在同一距离处的计算误差,得到了4阶为该仿真条件下的最优泰勒展开阶数,最后分别对9个分布密集的点目标和真实场景目标进行回波模拟和成像。点目标仿真结果表明,该方法在不影响回波信号性能的前提下可以使生成回波信号的时间减少53%,速度提升2倍;真实场景仿真结果表明,该方法可以应用于大场景的回波模拟。

基于改进时间卷积网络的短期光伏出力概率预测方法

为提高光伏出力的预测精度,提出基于改进时间卷积网络的短期光伏出力概率预测方法。首先,通过递归特征消除确定特征数量,采用分组整合方法进行特征选择;然后,采用变分模态分解处理光伏出力序列;最后,构建一种结合注意力机制的改进时间卷积网络预测模型,得到未来时刻不同分位数下的预测值,再利用核密度估计得到概率密度曲线。实验结果表明,提出方法具有更高的预测精度,可有效反映光伏出力的不确定性。

抗肿瘤治疗的肺腺癌患者发生静脉血栓栓塞的情况及危险因素分析

背景与目的静脉血栓栓塞(venous thromboembolism,VTE)是癌症患者最常见的并发症,也是癌症患者死亡的第二大原因。肺腺癌患者发生VTE的管理重点在于早期、及时发现危险因素。本研究旨在调查抗肿瘤治疗的肺腺癌患者VTE发生现状,探讨在抗肿瘤治疗过程中发生VTE的影响因素,为VTE的早期识别和筛查提供依据。方法收集2019年12月-2021年5月于南京医科大学第一附属医院确诊为肺腺癌且行抗肿瘤治疗患者的临床资料,分别采用Cox单因素及多因素回归分析、Kaplan-Meier曲线和Log-rank检验比较独立危险因素影响VTE发生的差异。结果Cox回归单因素及多因素分析显示,VTE病史、靶向药物治疗、放疗是抗肿瘤治疗肺腺癌患者VTE发生的危险因素(P<0.05)。Kaplan-Meier曲线和Log-rank检验比较独立危险因素发现VTE病史、靶向治疗、放疗患者的VTE发生率更高(P<0.05)。结论有VTE病史、放疗、靶向治疗是VTE发生的高危因素,对于这类影响因素的早期识别和筛查有助于今后临床实践中VTE的防控和管理。

一种高光谱遥感影像无损压缩方法与应用

针对遥感影像巨大数据量给传输、存储造成巨大压力和压缩比低的问题,本文提出了一种改进的自适应波段重排和最小均方误差预测的高效无损压缩方法。该方法能自适应地确定波段的最佳顺序,并根据最小均方误差预测充分利用这种排序相关性消除影像冗余。首先,该方法对高光谱影像波段自适应分组,在每个组内利用最小生成树算法排序,以提升相邻波段的谱间相关性。然后,对组内波段自适应地选择上下文进行谱间和谱内预测,去除高光谱影像的冗余。最后,对预测残差进行二进制算术编码去除统计冗余,完成高光谱影像无损压缩。基于资源一号高光谱影像的试验结果表明,本文方法有效利用了谱内、谱间相关性,改善了预测性能,优于常用的压缩方法。