mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
基于镜头分割与空域注意力模型的视频广告分类方法

随着视频广告在检索和用户推荐等领域的广泛应用,视频广告的分类成为一个重要问题。与现有视频分类任务不同,视频广告有其自身的特点:1)在时域上,产品对象在广告视频中的出现具有非周期性和稀疏性的特点,这使得分类任务需要排除大量与视频类别不相关的视频帧的干扰,利用少数相关视频帧进行分类;2)在空域上,视频帧中除产品外,还包含复杂背景的问题,这使得有效捕捉产品信息变得困难。为了解决上述问题,文中提出了一种基于镜头分割和空域注意力模型的视频广告分类方法,简称SSSA。针对视频中存在的大量干扰帧,文中使用基于镜头切换的分割方法采样视频帧。针对视频帧中包含复杂背景,文中在网络中引入视觉注意力机制帮助网络从产品相关区域提取判别性的特征。为了验证所提方法的有效性,构建了一个包含1000多个视频广告的数据库(简称TAV)并收集了眼动数据来训练注意力模型。实验结果显示,提出的SSSA视频分类方法比现有的视频分类方法在性能上提升了10%。
灰狼优化算法研究综述

灰狼优化(Grey Wolf Optimization,GWO)算法是一种新兴的群体智能优化算法,因简单高效而被成功应用于诸多领域。文章阐述了灰狼优化算法的搜索机制和实现过程,分析灰狼优化算法的特性,对目前GWO算法的相关改进及应用进行综述。重点对GWO算法的改进策略,包括种群初始化的改进、搜索机制的改进、参数的改进等进行了描述,对GWO算法在参数优化、复杂函数优化和组合优化等方面的应用进行了讨论。最后,对GWO算法的未来改进策略和实际应用进行了展望。
一种新的基于脑电信号相似性分析的癫痫性发作自动检测方法

癫痫是最常见的神经系统疾病之一。脑电图是大脑电活动的记录,已成为检测癫痫发作的一种有效工具。如何通过数据分析以挖掘癫痫脑电的本质特征,是实现癫痫性发作自动检测的关键。提出了一种新的脑电信号相似性的分析方法,进而在这一方法的基础上定义了待测脑电与模版脑电之间的最大余弦相似度为癫痫脑电特征,并将其应用于癫痫性发作的自动检测。采用BONN和CHB-MIT两个公开数据库来验证该文所提方法的性能。和已有方法相比,该文所提自动检测方法将检测准确率从97.53%提高至99.85%。该文所提出的脑电信号相似性分析方法可以成功应用于癫痫性发作的自动检测。
不同氮素形态、pH对茶树元素吸收及有机酸含量影响

以茶树龙井43为材料,利用营养液水培试验研究了不同氮素形态、pH对茶树体内阴阳离子和有机酸的影响,初步明确茶树养分吸收与氮素形态及pH的关系。结果表明,与NO_3~--N处理相比,NH_4~+-N处理提高了茶树成熟叶中N、Fe、Cl~-的含量以及根中N、SO_4~(2-)含量,但是NH_4~+-N处理降低了茶树对Ca、Mg、B、Mn、Zn的吸收,也减少了成熟叶中SO_4~(2-)、根中H_2PO_4-的累积量。与其他处理相比,NO_3~--N处理提高了成熟叶中苹果酸、草酸、柠檬酸浓度。茶树对养分的吸收、积累也与介质pH有关,尤其是pH与氮素互作时。在NO_3~--N处理下,pH 6.0显著提高了茶树对B、Mn、Zn的吸收和根中K、Ca、Mg浓度。茶树中有机酸含量受pH影响较大,与pH 4.0和pH 5.0相比,pH 6.0提高了茶树成熟叶中苹果酸、柠檬酸、草酸浓度以及根中草酸浓度。茶树对养分的吸收、积累与自身体内有机酸浓度有较好的相关性,茶树中全氮含量与柠檬酸、草酸浓度具有显著负相关性,而阳离子Zn~(2+)、Ca~(2+)、Mg~(2+)、Mn~(2+)含量与柠檬酸、草酸浓度具有显著正相关性。
渤海海域辽西凹陷北部走滑断裂特征及地质意义

利用研究区的地震勘探资料对辽西凹陷北部断裂体系进行分析,发现区内存在典型的走滑断层,这些走滑断裂均在前新生界基底收敛于新生代辽西凹陷中心部位,应该为先存基底断层在新生代始新世沙河街组三段沉积以来(40 Ma左右)右旋走滑再活动的产物。其与辽河西部凹陷内新生代郯庐右旋走滑断层可较好地延伸走向相连或平行相接,在活动时间和展布特征上与辽河拗陷陆上部分及辽东凹陷内的新生代郯庐右旋走滑断层均具有很好的走向连续一致性,这表明40 Ma以来,郯庐断裂带在整个辽河拗陷均具有东西两支平行展布的特征,且该特征应源于郯庐断裂带在该区前新生代东西两支的发育模式。区内走滑断层的存在,在凹陷内部形成系列洼中隆构造构成的中央构造带,这一构造带是油气聚集的有力圈闭发育区带。
人非理性且难教化?论支持自由家长主义的证据

基于心理学的研究,自由家长主义者认为人们的思维有个体难以克服的、根深蒂固的系统性缺陷,并难以通过教育来避免和消除,因此主张因势利导,仰仗外部专家的"助推"把人们的行为引导到正确方向。然而,从生态理性的角度看,人们依照自由家长主义者所谓的认知偏差做出的选择未必导致糟糕的结果,而依照自由家长主义者所推崇的理性方法做出的选择也未必导致理想的结果。本文分析了自由家长主义者用来支持助推的证据后发现:(1)它们源于一些研究者对"何为理性"的狭隘定义,误解了人类理性的本质;(2)它们对研究结果进行了选择性的报告,忽视了与这些证据相反的证据。通过这些分析,我们认为"人非理性且难教化"这一自由家长主义者的论断过于武断并有失偏颇。投入教育,教会人们如何精明老练地处理风险不仅是可行的,而且是替代助推的一个更为持久有效的解决方案。
乳酸菌细菌素生物合成机制、抑菌机制及应用研究进展

细菌素具有抗食源性致病菌和食品腐败菌的特点,可以作为在食品中应用的天然、无毒抗菌剂。但由于细菌素的抑菌机制复杂多样,尚未完全解析,以及抑菌效果受诸多因素影响,导致在食品领域的实际应用十分有限。该文将对细菌素的筛选和鉴定方法、抑菌机制及包埋技术的最新研究进展进行综述,以促进细菌素的研究和应用。
七种坚果仁中多酚、三萜含量及其抗氧化活性比较

坚果因富含抗氧化等活性成分已成为备受推崇的休闲食品。该研究将核桃、巴旦木、银杏果、花生、葵花籽、野生和种植香榧仁进行对比,评价7种坚果仁的活性成分含量及其抗氧化能力差异。结果表明,不同坚果的主要活性成分和抗氧化能力存在显著差异( P< 0.05) 。葵花籽仁和核桃仁中分别具有最高的总黄酮( 35.16 mg QuE/g DM)和总酚含量( 9.69 mg GAE/g DM)(槲皮素,quercetin equivalent,QuE;干原料,dry material,DM;没食子酸,gallic acid equivalent,GAE) ,(齐墩果酸,oleanolic acid equivalent,OAE) ,其次为种植香榧仁;种植香榧仁具有最高的总三萜含量( 4.37 mg OAE/g DM) ,其次为核桃仁。抗氧化实验表明,种植香榧仁提取物具有最高的DPPH·和ABTS~+·清除能力,其IC_(50)值分别为0.08 mg E. /mL和0.07 mg E. /mL(提取物,extract. E. ) ,但核桃仁提取物的Fe~(3+)还原能力最高,其槲皮素当量还原能力为115.25 mg QuE/g E. ,种植香榧仁的还原能力次之。以上结果表明,种植香榧仁具有较高的活性成分含量和抗氧化活性,是优于巴旦木、银杏果、花生和葵花籽仁的天然抗氧化剂资源。
米曲霉AAP新基因的异源表达及其酶学性质研究

通过生物信息学分析发现了米曲霉( Aspergillus oryzae)中属于氨肽酶M18家族的新成员天冬酰胺氨肽酶( AAP)基因,经反转录克隆获得该基因,实现了其在毕赤酵母GS115中的表达,同时研究了重组AAP的酶学性质及其在大豆蛋白水解中的应用。结果表明,重组AAP的分子质量约54.0 kDa,在较广的pH范围内有活性( pH 6.0 ~ 9.5) ,最适反应温度和pH分别为50 ℃和7.0,Zn~(2+)和Ca~(2+)对该酶起促进作用,EDTA能够显著抑制该酶的酶活。以Asp-pNA为底物时,K_m为0.42 mmol /L,V_(max)为21.57 μmol /( mL·min) ,该酶具有水解N末端为天冬氨酸和谷氨酸的底物特异性。重组AAP可显著降低大豆多肽的苦味,提高水解度,具有在食品中的应用潜力。
波流对人工岬头和海滩养护工程的响应

以新开河口至南山岸线为研究对象,为减少海岸侵蚀,在岸线两端修建人工岬头和包含水下沙坝的海滩养护工程.基于MIKE 21软件建立潮流和波浪耦合模型,研究波流动力对人工岬头和海滩养护工程的响应变化.人工岬头的挑流作用使得东西岬头前流速增加,但岬湾内部流速减小并在岬头后侧形成弱环流.海滩养护工程后沙坝坝顶有效波高略有增加,但沙坝之间有效波高有所削减,沙坝后侧海域波高明显减少;滩肩前方海域有效波高减小,涨潮期间波高减小量大于落潮期间波高减小量.人工岬头和海滩养护工程的共同作用可有效削减岬头和沙坝环抱海域特别是近岸的潮流和波浪,减少海岸侵蚀.
新老桥间超高性能混凝土拼接接缝性能试验

依托上海市济阳路高架新老桥拼接项目进行了基于高应变强化超高性能混凝土(UHPC)材料的拼接缝试验.试验采用非对称加载,目的是模拟新老桥的不均匀沉降.试验结果表明,UHPC拼缝整个受力破坏的过程大致可以分为3个阶段:弹性阶段、裂缝发展阶段、持荷至破坏阶段.在UHPC板下缘首先出现裂缝,之后UHPC板侧面出现大量微小裂缝,裂缝均以微裂缝簇的方式呈现,裂缝宽度发展缓慢,且沿着板高向上发展.UHPC转角为1.2%时裂缝宽度仅为0.16 mm,具有出色的裂缝控制能力.最终,UHPC板底出现主裂缝,横向钢筋和门筋屈服,钢筋布置方式满足试件破坏形态要求,说明试件的配筋合理.结合有限元模型对试验进行模拟,吻合度较高.利用有限元进行参数分析,发现增加接缝自由长度和减小接缝厚度可以有效增强接缝弯曲性能.由于UHPC材料进行接缝施工具有方便、快捷、性能优越等优点,提出基于上下部构造不连接类型的接缝形式,并给出具体配筋方案.
海底管线维护中底床表层稳定粗化层的构建

以东方岸外海域为例,计算了极端天气下不同水深条件构建稳定粗化层抛石颗粒的临界粒径;分析了影响粗化层稳定的不同因素,并对人工抛石构建粗化层提出建议.结果显示,在东方岸外30 m和60 m水深处,沉积物的中值泥沙粒径至少为30.33 mm和3.99 mm,才能抵御极端浪流的冲刷,且抛石层的厚度应至少为80.9 mm和10.8 mm,抛石层至少覆盖原始床沙的70%.粗化层的稳定性受颗粒隐蔽暴露效应、砂组分百分比、粗化层颗粒级配、覆盖厚度及覆盖百分比的共同影响,而抛石构建稳定粗化层的实质是对抛石粒径的合理选取及对细粒组分百分比的有效控制.另外,抛石级配的合理选择应受到重视,在施工过程中则需保证覆盖百分数和粗化层的覆盖厚度.粗细混合投放或者分层投放有利于更好地构建稳定粗化层.以上述方法构建稳定粗化层可为海底管道工程设施的维护提供有效支持.
One-step electrodeposition fabrication of Ni_3S_2 nanosheet arrays on Ni foam as an advanced electrode for asymmetric supercapacitors

Ni_3S_2 nanosheet(NS)arrays on Ni foam were fabricated by a simple one-step electrodeposition strategy, and used as a kind of electrode material for asymmetric supercapacitors. The Ni_3S_2 NS arrays are interconnected, which can be regarded as bridges between these individual nanoparticle units. The electrochemical performances were evaluated by cyclic voltammetry and chronopotentiometry techniques in a three-electrode system. The Ni_3S_2 NS arrays display a specific capacitance of 773.6 F g~(–1)at 1 A g~(–1), and excellent rate property of 84.3% at 10 A g~(–1). The performance of the Ni_3S_2 NS arrays was further investigated in an asymmetric supercapacitor for potential practical application. The asymmetric supercapacitor using the Ni_3S_2 electrode and reduced graphene oxide electrode as positive and negative electrodes, respectively, exhibits an energy density of 41.2 W h kg~(–1)at 1.6 kW kg~(–1). When up to 16 kW kg~(–1), it holds 25.3 W h kg~(–1). These excellent electrochemical performances are attributed to the improved electronic conductivity and rich redox reaction sites from Ni_3S_2 NS arrays. Our results indicate that the Ni_3S_2 NS arrays have great potential for supercapacitors.
An in-situ room temperature route to CuBiI_4 based bulk-heterojunction perovskite-like solar cells

Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite- like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(CuBiI_4)thin films directly on ITO substrate at room temperature, by utilizing a Bi-Cu alloy layer as precursor. X-ray diffraction and transmission electron microscopy(TEM)results verified the formation of well crystallized CuBiI_4 thin films with [222] orientation. The transient photovoltage(TPV)analysis revealed that the CuBiI_4 is an n-type semiconductor with a suitable band gap of ~1.81 eV, preferable to photoelectric conversion compared with CH_3NH_3PbI_3. It is very interesting that the subsequent spin-coating process of the classical Spiro-MeOTAD organic solution with TBP and acetonitrile resulted in a dense and smooth CuBiI_4:Spiro- MeOTAD bulk-heterojunction film. The preliminarily fabricated simple sandwich structures of ITO/CuBiI_4:Spiro-MeOTAD/ Au hybrid solar cell devices displayed efficient photovoltaic performance with the PCE up to 1.119% of the best sample. The room temperature direct metal surface elemental reaction(DMSER)method may provide a new insight for all-inorganic lead free perovskite-like A_aB_bX_x compounds and high performance photovoltaic devices.
New-type highly stable 2D/3D perovskite materials: the effect of introducing ammonium cation on performance of perovskite solar cells

Perovskite solar cells(PSCs)have drawn wide attention due to the rapidly rising efficiency which presently attains over 23%. However, problems of instability continue to plague the high-efficiency devices impairing their practical applications. Here, by firstly introducing smaller-size NH_4~+ into(FAPbI_3)_(0.85)(MAPbBr_3)_(0.15)(FA/MA)to form a novel 2D- 3D mixed structure, we designed and prepared new-type hybrid perovskite materials of [(NH_4)_(2.4)(FA)_(n–1)Pb_nI_(3n+1.4)]_(0.85)(MAPbBr_3)_(0.15)(n=3, 5, 7, 9 and 11)(A/FA/MA)and used them as absorber in solar cells. Especially, unlike the reported 2D/ MD perovskite perovskites based on larger-size ammonium salts; A/FA/MA perovskites are the first to display red-shift light absorption and decreased band gaps in comparison to normal perovskites. Consequently, when n=9, the A/FA/MA device shows outstanding performance with a solar to electric power conversion efficiency(PCE)of 18.25% and negligible hysteresis. When the encapsulated A/FA/MA perovskite device was soaked in full sunlight for 1,000 h, the PCE remains almost unchanged. Moreover, the unsealed A/FA/MA PSCs maintain 90% of their initial PCE when aged at high humidity conditions over the same 1000-h time period. Our findings provide a guide for the future development of such novel perovskites and it is helpful to select more suitable ammonium salt to obtain highly efficient and stable 2D-3D PSCs.
Ball-flower-like carbon microspheres via a threedimensional replication strategy as a high-capacity cathode in lithium–oxygen batteries

The robust porous architectures of active materials are highly desired for oxygen electrodes in lithium– oxygen batteries to enable high capacities and excellent reversibility. Herein, we report a novel three-dimensional replication strategy to fabricate three-dimensional architecture of porous carbon for oxygen electrodes in lithium–oxygen batteries. As a demonstration, ball-flower-like carbon microspheres assembled with tortuous hollow carbon nanosheets are successfully prepared by completely replicating the morphology of the nanostructured zinc oxide template and utilizing the polydopamine coating layer as the carbon source. When used as the active material for oxygen electrodes, the three-dimensional porous architecture of the prepared ballflower- like carbon microspheres can accommodate the discharge product lithium peroxide and simultaneously maintain the ions and gas diffusion paths. Moreover, their high degrees of defectiveness by nitrogen doping provide sufficient active sites for oxygen reduction/evolution reaction. Thus the prepared ball-flower-like carbon microspheres demonstrate a high capacity of 9,163.7 mA h g~(–1)and excellent reversibility. This work presents an effective way to prepare three-dimensional architectures of porous carbon by replicating the controllable nanostructures of transition metal oxide templates for energy storage and conversion applications.
Directly grown nanostructured electrodes for highpower and high-stability alkaline nickel/bismuth batteries

Bismuth oxide(Bi_2O_3)has received great attention as an anode material for alkaline nickel/bismuth(Ni/ Bi)batteries due to its high theoretical capacity and easy preparation. However, the generally poor conductivity of metal oxides and the instability of Bi_2O_3 during cycling severely limit the device performance. Herein, we present the use of directly grown Bi_2O_3 nanoflake film with kinetic advantages as the anode for Ni/Bi batteries. Particularly, glucose-derived carbon is integrated onto the surfaces of nanoflakes, which not only enhances the electron transfer but also buffers the conversion- reaction induced volume expansion of Bi_2O_3, helping maintaining the cycling stability of the film. The resulting Bi_2O_3@C electrode exhibits high specific capacity, excellent rate performance(can be charged within 6.7 s), and good cycle stability(~1,200 times; fading rate of only 0.011% per cycle). When assembled with a nickel oxide(NiO)nanosheet array cathode in basic electrolyte, a fully binder-free Ni/Bi battery is obtained, which delivers maximum energy and power densities of 34.29 W h kg~(–1)and 12,159.8 W kg~(–1), respectively, and good cycling performance. The power density is even much superior to that of many hybrid/asymmetric supercapacitors. Our work suggests a new generation of thin-film Ni/Bi batteries for potential high-power electronic applications.
N-doped carbon-coated Co_3O_4 nanosheet array/ carbon cloth for stable rechargeable Zn-air batteries

Although the application of various nonprecious compounds as the air cathodes of Zn-air batteries has been explored, the construction of highly efficient selfsupported Co-based electrodes remains challenging and highly desired given their outstanding electrocatalytic activity and cost-effectiveness. Herein, we fabricated a three-dimensional(3D)self-supported electrode based on N-doped, carbon-coated Co_3O_4 nanosheets grown on a carbon cloth(i.e., NC-Co_3O_4/CC)through the electrochemical deposition and carbonization. When used as a binder-free electrode for oxygen evolution reaction(OER), the NC–Co_3O_4/CC electrode demonstrated excellent electrocatalytic activity with an overpotential of 210 mV at 10 mA cm~(–2)and a Tafel slope of 79.6 mV dec~(–1). In the Zn-air battery test, the electrode delivered a small charge/discharge voltage gap(0.87 V at 10 mA cm~(–2))and exhibited high durability without degradation after 93 cycles at the large current density of 25 mA cm~(–2). The durability of our electrode was superior to that of a commercial Pt/C+RuO_2 catalyst. The excellent performance of NC–Co_3O_4/CC could be attributed to the presence of 3D structures that promoted electron/ion transfer. By the absence of a binder, the carbon coating improved electron conductivity and promoted electrochemical stability. Moreover, N doping could be used to adjust the C electron structure and accelerate electron transfer. The present study provides a facile and effective route for the synthesis of various self-supported electrodes that fulfill the requirements of different energy storage and conversion devices.
Acenaphthylene-imide based small molecules/TiO_2 bilayer as electron-transporting layer for solutionprocessing efficient perovskite solar cells

It is of great significance to design and synthesize highly efficient n-type organic small molecules as electron-transporting layer(ETL)materials to achieve high performance planar perovskite solar cells(PVKSCs)with lowtemperature solution-processing. In this article, acenaphthylene- imide based small molecules AI1, AI2 and AI3 were developed with lower-lying LUMO energy levels and were further applied as non-fullerene ETL materials for solutionprocessed PVKSCs. When TiO_2/AIX bilayer was used as ETL, an average power conversion efficiency(PCE)of 15.0% was achieved for TiO_2/AI1 based PVKSCs with conventional configuration, while pristine TiO_2 based devices presented a PCE of 11.7% only. All the results demonstrate that acenaphthylene- imide derivatives could be promising ETL materials to accomplish low-temperature solution-processed high performance PVKSCs.
Controllable dispersion and reunion of liquid metal droplets

Liquid metal(LM)micro-droplets have been widely used in microfluidics, drug-loaded nano-system and micro-nano machine due to its excellent properties. However, there still exist difficulties in succinctly dispersing a bulk of LM into micro-droplets due to the large interfacial tension. Besides, the controllable switching between droplet dispersion and reunion is yet to be realized. Herein, a practical and efficient method for dispersing LM was proposed and the controllable switching between dispersion and reunion of LM droplets was achieved. LM micro-droplets were produced by vibrating the LM immersed in a mixture of N,N-dimethylformamide(DMF)and polyvinyl chloride(PVC). The experimental results show that the size distribution of LM micro-droplets could be tuned by controlling the vibration frequency. More intriguingly, the dispersion and reunion of LM droplets can be switched intelligently through tuning the vibration frequency and amplitude. Furthermore, optical properties of the LM micro-droplet coating were evaluated to display potential applications. A self-driven motion of PVCcoated LM could be achieved by utilizing the produced LM micro-droplets based on the Marangoni effect, which holds promising value for developing future transport tool of LM droplets. The present work suggests an entirely feasible method for dispersing and utilizing LM droplets, which is of great significance for promoting the development of LM micro-droplet science and technology.
Facile fabrication of interconnected-mesoporous TNb_2O_5 nanofibers as anodes for lithium-ion batteries

Niobium pentoxide(Nb_2O_5)has been extensively studied as anode materials for lithium ion batteries(LIBs)due to its good rate performance and safety advantages. However, the intrinsic low electronic conductivity has largely restricted its practical application. In this work, we report the construction of mesoporous T-Nb_2O_5 nanofibers by electrospinning followed by heat treatment in air. The interconnected mesoporous structure ensures a high surface area with easy electrolyte penetration. When used as anodes for LIBs, the mesoporous Nb_2O_5 electrode delivers a high reversible specific capacity of 238 mA h g~(–1)after 1,000 cycles at a current density of 1 A g~(–1)within a voltage range of 0.01–3.0 V. Even at a higher discharge cut-off voltage window of 1.0–3.0 V, it still possesses a high reversible capacity of 166 mA h g~(–1)after 200 cycles. Moreover, the porous Nb_2O_5 electrode also exhibits excellent rate capability. The enhanced electrochemical performances are attributed to the synergistic effects of porous nanofiber structure and unique crystal structure of T-Nb_2O_5, which has endowed this material a large electrode-electrolyte contact area with improved electronic conductivity.
支气管肺泡灌洗液GM试验联合血清GM试验对侵袭性肺曲霉病的诊断价值

目的分析支气管肺泡灌洗液半乳甘露聚糖试验(BALF-GM试验)联合血清GM试验诊断侵袭性肺曲霉病(IPA)的准确性及诊断价值。方法选择2016年1月至2018年6月济宁医学院附属医院疑似真菌感染患者,其中送检BALF标本190例,送检血清标本4 787例。所有患者按照《肺真菌病诊断和治疗专家共识》的分级标准分为临床确诊IPA、临床诊断IPA、拟诊IPA、排除IPA。分析BALF和血清GM试验结果与临床实际诊断的符合率;绘制受试者工作特征曲线(ROC),评估BALF与血清GM试验单独或联合检测对IPA的诊断价值。对免疫功能正常和免疫功能异常患者进行亚组分析,比较BALF与血清GM试验单独或联合检测的敏感度和特异度。结果BALF-GM试验阳性率为46.8%(89/190),血清GM试验阳性率为10.4%(497/4 787)。有156例患者同时送检了BALF-GM试验与血清GM试验,其中BALF与血清GM试验均阳性44例,与临床确诊的符合率为93.2%(41/44);BALF-GM试验阳性、血清GM试验阴性34例,与临床确诊的符合率为64.7% (22/34);血清GM试验阳性、BALF-GM试验阴性56例,与临床确诊的符合率为48.2%(27/56);BALF与血清GM试验均阴性22例,与临床排除的符合率为90.9%(20/22)。ROC曲线分析显示,BALF联合血清GM试验对IPA的诊断价值优于BALF-GM试验或血清GM试验单独检测〔ROC曲线下面积(AUC):0.992比0.983、0.976〕,其敏感度、特异度、阳性预测值(PPV)、阴性预测值(NPV)分别为95.3%、87.0%、93.2%和90.9%。亚组分析结果显示,89例BALF-GM试验阳性患者中,免疫功能正常85例(95.5%),情况未知4例(4.5%);497例血清GM试验阳性患者中,免疫功能正常12例(2.4%),免疫功能异常372例(74.9%),不确定113例(22.7%)。ROC曲线分析结果显示,对于免疫功能正常的患者,BALF-GM试验诊断IPA的敏感度高于血清GM试验(95.6%比88.9%);而对于免疫功能异常的患者,血清GM试验诊断IPA的敏感度高于BALF-GM试验(91.8%比89.9%)。结论BALF和血清GM试验结果与临床实际诊断的一致性较高,且两者联合检测对IPA的诊断较单独检测更有临床价值,尤其适用于免疫功能未知的患者。
附着物对冬季菹草叶绿素荧光活性的影响

为探究附着物去除对低温环境下菹草Potamogeton crispus的胁迫作用及其变化,选择全球分布最广且冬季生长的菹草为研究对象,于2016年1月14-19日通过原位测量的方法,对比某静水池塘沉水植物茎叶表面附着物去除前后菹草叶片叶绿素荧光参数的变化情况。结果表明,与未去除附着物的对照组菹草叶片相比,去除附着物的处理组菹草叶片的最大光量子产量(Fv/Fm)仅在第一天随光合辐射强度的增加呈下降趋势,但相对电子传递速率(rETR)值仅在第一天随光合辐射强度的增加呈下降趋势,从试验第2天开始就逐渐恢复到与对照组相近水平(P>0.05)。研究表明,菹草本身对于附着物去除的适应能力可能非常迅速,而在低温环境下,附着物的遮光作用对低温条件下菹草易发的光抑制现象是一种保护。
翅碱蓬响应高盐胁迫的分子机制研究

为研究翅碱蓬Suaeda heteroptera响应高盐胁迫的分子机制,试验将翅碱蓬植株在高盐胁迫(856 mmol/L NaCl)和无盐(0 mmol/L NaCl)条件下处理2 h后,对植株分别进行全转录组测序。结果表明:通过RNA-seq分析共获得转录本147 176个,拼接后获得单基因(Unigene)84 545个;比较转录组学分析显示,与无胁迫组(对照)相比,高盐胁迫下翅碱蓬共检出144个差异表达基因,其中发生表达上调的有55个,发生表达下调的有89个;GO富集分析显示,差异表达基因主要分布在次生代谢、信号转导、光合作用电子传递等途径;KEGG富集分析显示,差异表达基因涉及的代谢通路有14个;对差异表达基因发生富集的5个主要代谢通路(光合作用、蔗糖与海藻糖代谢、植物激素信号转导、苯丙基类生物合成、半胱氨酸与甲硫氨酸代谢)进行了详细阐述,从分子水平探讨了翅碱蓬响应高盐胁迫的机制。本研究结果可为更深入研究翅碱蓬耐盐分子机制、挖掘耐盐关键基因提供数据资料。
高效除磷型底泥陶粒的制备及性能分析

以河道疏浚底泥为主要原料制备高效除磷型底泥陶粒。通过单因素实验和L_9(3~4)正交试验考察了造孔剂、水泥、烧结温度和保温时间对陶粒性能的影响,并研究了吸附饱和陶粒的再生方法。结果表明:高效除磷陶粒的最佳制备条件为造孔剂6.0 g,水泥6.0 g,烧结温度1 060 ℃,保温时间15 min。该条件下制得的陶粒空隙率60.20%,吸水率38.75%,破碎率与磨损率2.14%,盐酸可溶率1.60%,底泥质量分数0.77%,表观密度1 280 kg·m~(-3),堆积密度510 kg·m~(-3),满足CJ/T 299-2008《水处理用人工陶粒滤料》性能指标要求;处理10.0 mg·L~(-1)含磷废水,磷去除率可达95.55%;吸附饱和陶粒可采用2.0 mol·L~(-1)氢氧化钠进行再生。
春夏季温州雁荡山杉木林臭氧质量浓度垂直变化特征

森林中臭氧浓度不仅影响林木生长,也影响游憩环境质量,是森林康养环境研究的热点之一。根据2017年春夏两季对温州雁荡山国家森林公园内杉木Cunninghamia lanceolata林不同垂直高度臭氧浓度及气象因子昼夜24 h同步监测数据,分析了不同高度臭氧浓度的变化规律及其影响因素。结果表明:除春季H3(林冠上层)臭氧质量浓度日最大8 h均值达到中国二类环境功能区质量要求外(≤200 μg·m~(-3)),两季节中其余各高度臭氧质量浓度日最大8 h均值及小时均值均达到中国一类环境功能区质量要求(≤160 μg·m~(-3));春夏两季各高度臭氧质量浓度从小到大依次为H1(距地面1.5 m), H2(林冠中部)和H3,且春季H1, H2和H3臭氧质量浓度日均值差值高于夏季;两季各高度臭氧质量浓度均为日间高、夜间低,且高值出现于11:00-15:00,低值出现于5:00;春夏两季各高度臭氧质量浓度小时均值与温度、风速呈正相关,与相对湿度呈负相关;春季各高度臭氧质量浓度与气压呈负相关。总体来讲,在雁荡山杉木林环境中,以臭氧质量浓度变化规律为游憩及游憩设施布设标准,在时间的选择上,夏季比春季更适合出游,且夜间优于白天;在空间的选择上,建议选择林下及树冠中部布置游憩设施,如林下栈道及空中栈道或森林木屋等设施。
油茶不同器官氮、磷、钾化学计量特征随年龄的变化

油茶Camellia oleifera为中国特有的食用油料树种,但关于油茶不同器官氮、磷、钾的生态化学计量特征的认识还不够充分。以浙江省常山县油茶人工林为对象,通过测定不同年龄油茶叶片、枝条、主干、根系和果实中氮、磷、钾质量分数,探讨了油茶不同年龄各器官氮、磷、钾化学计量特征及在各器官中的分配规律。结果表明:油茶氮质量分数从大到小依次为叶片、枝条、根系、果实、主干,磷质量分数从高到低依次为叶片、枝条、果实、根系、主干,钾质量分数从高到低依次为果实、叶片、根系、枝条、主干;随年龄的增加,枝条中的氮、磷质量分数逐渐增大,而其他器官中氮、磷质量分数先增大后减小,钾质量分数先增高而后降低。油茶各器官氮磷比(N∶P)为3.91~10.68,氮钾比(N∶K)为0.33~1.31,钾磷比(K∶P)为3.71~19.08;随年龄的增长,油茶果实N∶P逐渐增高,而其他器官N∶P则先增高而后降低,叶片、枝条、根系和果实的N∶K逐渐增大,叶片、主干和果实K∶P先升高而后下降,枝条、根系的K∶P逐渐降低。油茶叶片的氮、磷平均分配比例为31.4%和28.6%,钾在根系中具有最高的分配比例,平均占比达30.5%。影响油茶生长的限制元素是氮,在生产经营程中,可适当增施氮。
宝华玉兰生存群落的自组织特征映射网络排序与分类

为了解国家Ⅱ级保护植物宝华玉兰Magnolia zenii的种群分布规律及其濒危原因,进一步揭示宝华玉兰野生种群与群落及环境之间的生态关系,应用自组织特征映射网络(SOM)对宝华玉兰生存群落进行了排序和分类,以期为保护和管理宝华玉兰种群野生种质资源提供理论依据和新的方法。结果如下: ①群落结构分析表明,宝华玉兰天然更新缺乏,且紫楠Phoebe sheareri,建始槭Acer henryi等优势种占据了主要生存空间与资源,影响了宝华玉兰种群增长和发展,使其在群落中处于不稳定地位; ②SOM将40个样方进行聚类分析,得到7个群落类型。不同群落类型之间的物种组成存在差异,界限清晰,排序结果与优势种实际分布情况吻合,说明SOM的分类结果具有合理性; ③环境因子可视化分析揭示了宝华玉兰分布于坡度较缓的半阳坡,种群分布主要受到坡向和坡度2个环境因子的影响,由于宝华玉兰自身生长过程中对环境要求的特殊性和不适应性,造成了其濒危现状; ④SOM具有高度非线性拟合的特点,且能够同时进行排序和分类,并将分类结果可视化,呈现样方之间的相似性,说明SOM应用于群落分类和排序,反映种群与群落及环境之间的生态关系是合适的。
新型多叶轮潜水搅拌机流场特性

为提高搅拌机搅拌效果,针对各种形状的污水处理池,设计出系列新型多叶轮潜水搅拌机.文中基于ANSYS Fluent 15.0,对2种新型多叶轮潜水搅拌机搅拌流体进行计算,展开深入研究.结果表明:新型双向潜水搅拌机和新型双层潜水搅拌机搅拌水池内流体有效轴向推进距离分别是同叶轮的传统潜水搅拌机的2.0倍和1.8倍,池内流体平均流速分别为0.194m/s和0.215m/s,与传统潜水搅拌机搅拌流体平均速度0.203m/s接近.新型双向潜水搅拌机池内最大速度沿轴向呈现马鞍形分布,且流体速度差较大,仅有73.2%流体的流速大于0.050m/s,且低速区存在于水池中上部,其更适用于狭长且不深的水池.新型双层潜水搅拌机搅拌水池内流体最大速度分布沿轴向呈现双曲线递减分布,78.71%流体的流速在0.100~ 0.300m/s,池内低速流体仅占1.55%.故新型双层潜水搅拌机和新型双向潜水搅拌机搅拌性能明显优于同叶轮的传统潜水搅拌机.研究结果可为潜水搅拌机的实际工程应用提供参考.
基于水生态足迹的山东省水资源利用与经济发展分析

为了研究水资源利用情况与经济增长的协调性,提出了一种考虑不同受纳水体的水生态足迹计算方法,并以此计算了山东省2003-2015年水量与水质生态足迹,构建了宏观方面的协调发展脱钩评价模型与微观方面的协调度理论,对水资源消耗与经济增长之间的协调关系进行评价.结果表明山东省水生态足迹总体呈现波动上升趋势,水量生态足迹显示出明显的农业主导型;水质生态足迹计算中,地表与地下水质生态足迹比例约为3 ∶ 4;地表水质生态足迹中,2003-2009年硝态氮为决定性污染物,2010-2015年总磷为决定性污染物;地下水质生态足迹则表现为硝态氮主导.人均GDP增长与水生态足迹由弱脱钩的初级协调向强脱钩的中级协调转变,初步说明山东省水资源与经济的协调发展呈现改善趋势.
导叶时序位置对离心泵叶片载荷影响的数值模拟

采用结构化网格及SST湍流模型,对不同导叶时序位置下离心泵内部流场进行三维非定常数值模拟,并对模拟结果进行试验验证,研究时序效应对叶轮叶片和导叶叶片载荷的影响.结果表明:当隔舌大约处在2个导叶中间(cl0,cl5位置)时,蜗壳不对称作用对叶轮内部流场影响降低,叶轮叶片压力面载荷增大,叶轮做功能力较好;当叶片逐渐靠近蜗壳隔舌时,蜗壳不对称作用对叶轮内部流场影响增大,叶片出口吸力面大于压力面载荷的位置逐渐向叶片中段偏移,导致叶轮做功能力逐渐降低;导叶叶片载荷分布受导叶与隔舌相对位置的影响较为明显.当导叶叶片尾缘靠近蜗壳隔舌时,导叶叶片载荷出现吸力面大于压力面的情况.
叶片出口角对化工离心泵性能的影响

为了研究叶片出口角对化工离心泵性能的影响,以一台比转数为180的化工离心泵为研究对象,将叶片出口角从22°依次增大到27°,37°和47°.应用ANSYS 14.5软件进行数值计算,结果表明:叶片出口角对外特性影响显著,适当增大叶片出口角可以提高扬程及效率,但也不宜过度增大到47°;随着叶片出口角的增大,叶轮进口的低压区域逐渐向叶轮出口方向扩大,压力分布趋于紊乱,且在工作面附近有逆压梯度存在,会聚集不稳定的低压流体;在额定工况下,叶片出口角小于37°时,压力脉动幅值较小,且高频脉动很小;次主频有随叶片出口角的增大向低频处转移的趋势;4个方案叶轮所受径向力都是在额定工况下达到最小,并在小流量下差异性最大;不同工况下叶片出口角为27°的叶轮所受径向力最小,这说明对非定常特性的影响,叶片出口角存在一个最优值.此外,针对叶片出口角为22°的模型进行了性能试验,对比发现数值计算的结果是可信的.
BP和RBF神经网络预测射流式喷头射程对比

为了探究适合全射流喷头多因素下射程的预测模型,通过改变喷头工作压力、安装高度、喷嘴直径、喷头仰角共4个参数,对射程进行测量.基于BP神经网络和广义径向基(RBF)神经网络的基本原理和算法,建立了全射流喷头射程预测的BP和RBF神经网络模型,并分析BP和RBF神经网络的预测性能.结果表明射程与工作压力、喷嘴直径呈非线性关系;当喷头在1.2m安装高度、27°仰角、4~10mm喷嘴直径时,压力增大到0.4MPa,射程趋于极限,并且安装高度与射程呈正相关关系.BP与RBF神经网络均能较好地表达全射流喷头射程与主控因素之间的非线性关系.在训练时间方面,RBF网络比BP网络慢8.05s;预测过程中,BP网络在每次运行程序时的预测结果不一定相同,而RBF网络则不会出现此问题,且RBF网络预测值与实测值之间的平均绝对误差比BP网络的小3.55%.从网络预测总体效果观察,RBF神经网络预测喷头射程具有更好的推广能力.
面向卷积神经网络的FPGA设计

近年来,卷积神经网络作为深度学习中的常用算法,被广泛地应用在计算机视觉的任务中. FPGA凭借它的高并行计算、低功耗和可重复配置的特点在实现卷积神经网络的多种加速器中显示了优异的特性.近几年,使用FPGA加速卷积神经网络的方法已经被人们广泛地探索,但是大部分设计的性能都受限于片上乘法器数量.快速算法在卷积操作中能够有效降低运算中乘法的数量,进而达到平衡资源的效果.本文首先介绍4种实现卷积神经网络的算法:传统的空间卷积算法、矩阵乘法、Winograd算法和FFT算法.同时介绍国内外对于不同算法在硬件上的实现,以及相应的优化手段,并且总结使用FPGA加速CNN的发展历程.
基于证据理论的结构非概率可靠性拓扑优化设计

考虑数据信息较少以及认知水平有限情况下的不确定性对于结构拓扑优化具有重要意义.本文引入证据理论处理不精确的数据信息,采用证据理论的不确定测度克服精确概率约束模型建立的困难,并结合拓扑优化策略,形成了基于证据理论的可靠性拓扑优化设计模型.为了提高不确定测度的计算效率,提出了仿生智能优化算法和不精确极值思想相结合的改进优化算法来降低焦元数目和极限状态函数极值求解所导致的计算量.通过两个桁架算例对所提方法进行验证,结果表明,确定性优化结果可能是不确定情况下的失效解,虽然基于证据理论的最优设计在重量和拓扑形式上相对于确定性优化结果偏保守,但具备抵抗不确定波动的能力.
基于首次超越概率理论的混凝土坝时变风险率研究

随着我国大坝安全管理工作逐渐由传统的工程安全管理向工程风险管理方向发展,在役大坝风险水平成为了越来越重要的研究课题.混凝土坝实际运行过程中受到众多随机不确定因素和模糊因素影响,导致大坝自身风险率具有显著的时变特性,本文尝试引入二元高斯算法采用并联体系方法计算混凝土坝系统时变风险率,将时变风险率分析问题转化为静态并联体系失效概率计算问题,通过在广义随机空间内采用JC法计算固定时刻混凝土坝风险率,并基于首次超越概率理论转化为混凝土坝时变风险率.最后,在工程算例分析中以某混凝土重力坝沿坝基抗滑失效为例,通过引入合理的抗力和荷载效应随机过程变量模型,采用该算法对混凝土重力坝抗滑稳定时变风险率进行了分析,验证了该模型的有效性,具有一定的理论和工程应用价值.