利用诱饵树防治薄壳山核桃星天牛效果探究

星天牛是薄壳山核桃上危害较严重的蛀干类害虫,防治难度较大。为探索薄壳山核桃星天牛绿色高效防治手段,本研究以存活率、平均生长量、受害株率、受害株率减退率、日均单株诱虫量和雌雄比为调查指标开展了以苦楝和复叶槭为诱饵树的引诱效果试验。结果显示,苦楝和复叶槭的存活率均较高,且苦楝的生长速度明显快于复叶槭;种植诱饵树后,薄壳山核桃的受害率逐年降低,控制在10%以内;与薄壳山核桃相比,两类诱饵树均对星天牛有明显的引诱效果(P<0.05),而诱饵树种间的引诱效果差异无统计学意义(P>0.05);不同诱饵树和不同年份引诱到的星天牛雌虫的平均腹卵量差异无统计学意义(P>0.05)。结合必要的营林和抚育措施,种植苦楝和复叶槭作为诱饵树并配合人工捕杀方式是一种高效绿色防治星天牛的方法。

香椿常见病虫害及综合防治措施

香椿用途广泛,是一种重要的经济树种。本文介绍了香椿常见的病虫害,并提出了包括耕作防治、物理防治、化学防治、生物防治在内的综合防治措施,旨在为其病虫害的防治提供参考,促进香椿产业的可持续发展。

长江滩地血防林建设与钉螺分布的相关性研究

本文以望江县国家级林业血防工程质量与效益监测点为依托,通过多年对钉螺分布、林草植物群落结构、林地经营模式、土壤理化性质、气候变化(水旱情状况)等生物和非生物要素的定量分析,研究血防林建设与钉螺分布的内在联系及其相关性。结果表明,(1)血防林建设显著降低了钉螺密度,监测点新造林活螺密度从0.6480~1.4250只/0.11 m^(2)下降至0.0558~0.1351只/0.11 m^(2)。(2)不同模式、季节、耕作方式和气候变化对钉螺的年际分布具有显著影响。活螺密度:遇旱下降、遇汛上升,间作<翻耕不间作<不翻耕不间作,秋季<春季及新造林<对照。(3)钉螺密度年际变化与土壤理化性质显著相关。滩地造林后,土壤含水量、毛管持水量、最大持水量、总孔隙度和全钾明显下降,而土壤的pH值、容重明显升高,林地土壤的诸多理化指标发生显著变化,导致钉螺密度显著降低(P<0.05)。(4)血防林建设改变了林下草本植物群落的物种组成,草本植物群落的多样性指数越高,抑螺效果越好;与钉螺密度显著相关的是草本植物群落物种的相对盖度。综上所述,血防林建设引起了滩地生物和非生物诸多要素的显著改变,不同要素的交互作用共同影响钉螺分布,导致钉螺密度显著降低,具有明显的抑螺效应。

生物质灰渣对甲基橙废水的去除性能及机制

为将资源化生物质灰渣用于甲基橙(MO)废水的处理,在明确MO初始浓度、pH值、反应时间和温度影响的基础上,探讨MO去除的潜在机制和效果提升途径。结果表明,MO的去除随MO初始浓度的增加而增加,并在80 mg/L时趋于平衡。pH值为2时有利于吸附的进行,且MO去除在12 h内较为迅速,24 h后趋于平衡。Langmuir模型可较好地模拟生物质灰渣对MO的吸附过程,表明该吸附过程属于单分子层吸附,且对MO的理论最大吸附量为25.2 mg/g。此外,灰渣吸附MO能较好地被二级动力学拟合,说明化学吸附是MO去除的主控机制。FT-IR光谱进一步表明吸附机制主要由静电、表面络合物或沉淀等共同作用。此外,添加H_(2)O_(2)(最终质量浓度4%)可使MO的去除率提高67.2%,是提升灰渣对MO去除性能的有效途径。

基于高通量测序探讨印楝素对薄壳山核桃林地土壤微生物的影响

使用不同浓度的印楝素对薄壳山核桃进行灌根处理,30 d后采集土壤样品进行高通量测序,比较分析不同浓度印楝素对不同土层深度土壤微生物多样性的影响。结果表明,薄壳山核桃深层土壤(50~55 cm)中细菌种类、丰度及均匀度受高浓度印楝素影响明显,其中鞘脂单胞菌科、硫还原菌科的菌类丰度下降较多;中层土壤(30~35 cm)中两个施药组的链霉菌科、芽单胞菌科、鞘脂单胞菌科的菌类丰度有所降低,低浓度印楝素处理组的各α多样性指数稍低;浅层土壤(10~15 cm)中施低浓度印楝素的链霉菌科、芽胞杆菌科、芽单胞菌科等菌类的丰度有所降低,但α多样性指数各组间差距不大。所有土壤样品中可识别真菌主要分属于子囊菌门、担子菌门和被孢霉门3门,施高浓度印楝素药液样品的担子菌门真菌所占比例下降明显,而未归类真菌比例增高。浅层和中层深度土壤样品中,施药组的丝盖伞科和发菌科的菌类丰度均有所降低,施高浓度印楝素的中层土壤(30~35 cm)中孢菌科和扁孔腔菌科的菌类丰度偏低,低浓度印楝素处理组的球盖菇科、间座壳科、毛壳菌科和红菇科的菌类丰度在不同土层中出现一定程度的升高。

易筋经功法锻炼治疗颈椎病的Meta分析

目的系统评价易筋经功法锻炼对颈椎病临床疗效的影响。方法检索中文数据库(知网、万方、CBM、维普)及英文数据库(Web of Science、PubMed、Cochrane Library、Embase)中所有易筋经治疗颈椎病的相关随机对照试验,检索时间为建库至2020年12月31日。研究者独自筛选文献,采用Revman 5.3软件对数据进行Meta分析。结果共纳入19篇文献,1541例患者。Meta分析结果显示试验组的总有效率明显高于对照组,差异有统计学意义[RR=1.16,95%CI(1.10,1.22),P<0.00001]。结论据目前临床研究证据表明,易筋经对颈椎病的临床疗效优于其他疗法,但由于相关文献较少,文献质量不高,仍需大样本、高质量的临床研究样本加以验证。

10%纳米阿维菌素悬浮剂防治美国白蛾田间药效试验

本试验利用10%纳米阿维菌素悬浮剂和10%纳米阿维·吡虫啉悬浮剂防治美国白蛾,以期了解其田间防治效果及安全性,为该产品的推广使用提供依据。结果表明,不同浓度的10%纳米阿维菌素悬浮剂和10%纳米阿维·吡虫啉悬浮剂对防治美国白蛾的防治效果有明显差异,其中4000倍的10%纳米阿维菌素悬浮剂处理防效最好,时效最快。

掺杂改性纳米铁氧体材料去除水体污染物的研究进展

纳米铁氧体材料结合了铁氧体的电磁特性和纳米材料的独特优势,使材料表现出优异的磁性和吸附性能,其作为吸附剂在污水处理中的应用具有操作简单、吸附容量高及易回收等优点。单一的铁氧体的吸附容量有限,因此对铁氧体材料进行改性显得尤为必要。概述了铁氧体的微观结构形貌和性能特点,并着重从掺杂改性方面综述了纳米铁氧体材料的制备研究进展,以及其在吸附废水中重金属、有机物、无机物等方面的应用进展,指出掺杂多金属可以大大改善铁氧体材料的磁性和吸附性能。最后对纳米铁氧体吸附剂的未来发展趋势进行了展望。

少阳病经证、腑证解析及临床应用

《伤寒论》中,太阳、阳明病篇皆可分经证、腑证,而少阳病是否可分,鲜有人关注。本文首先论述经证、腑证源流,阐明二者定义。后从《伤寒论》原书出发,结合其成书背景,表明伤寒六经辨证法与《内经》以“脏腑”为核心的思想保持一致,外邪传变必是由经至腑的过程。再通过对太阳、阳明经、腑证进行分析,得出少阳同样可分,并结合书中具体条文进行探究,得出少阳经证为小柴胡汤证、少阳腑证包括柴胡桂枝干姜汤证及大柴胡汤证,并结合现今临床病证进行说明,以冀其能更多运用于临床。

智能变电站母线合并单元改造方案优化

随着智能变电站运行技术的成熟,智能组件的改造需求越来越多,其中母线合并单元改造最为复杂,涉及母线上所有线路、主变、母联间隔,对于运行中的变电站有着重要影响。对某早期220 kV变电站扩建过程中母线合并单元改造方案进行了优化,对比了3种方案,给出了最优方案,并分析了现场工作的风险点,制订了分步实施的方案,有效减少现场施工风险,并成功实施。

大司天与明清温病代表医家之间的关系探讨

五运六气理论一直为中医理论中的重要组成部分,历代医家对此阐发丰富,"大司天"理论从更广阔的时空范围内概括了六十年间气象物候与疾病,使五运六气理论进一步发展。本文从大司天理论出发,简要说明其发展过程,并以明清时期兴盛的温病学派为例,分析学派中代表医家吴有性、戴天章、余霖及叶天士、薛雪、吴鞠通、王孟英的学术思想与其时值大司天之间的关系,并提出分析医家思想除可从大司天这一思路,还需结合多种因素进行综合分析。

水伏科学技术的发展、挑战与未来

近年来国际上的一系列研究发现功能材料与雨滴、水波、自然水蒸发和大气湿度等相互作用能直接输出电能,类比于光伏(photovoltaic)效应,这类生电现象被称为水伏(hydrovoltaic)效应。水伏效应现象最初发现于碳纳米材料与液体的相互作用体系,如2014年发现的石墨烯表面拖曳水滴发电的“拖曳势”、水面波动在石墨烯表面产生的“波动势”。

可重复使用运载火箭结构疲劳耐久性与可靠性展望

可重复使用火箭是当今世界运载火箭技术发展的重要方向。传统的一次性运载火箭只需要完成单次发射任务,通常使用高静强度安全系数来保证其结构可靠性。对于需要尽可能多地执行发射任务以提高经济效益的可重复使用运载火箭,结构疲劳耐久性与可靠性是静强度难以覆盖的。抗疲劳断裂性能与可靠性是高性能可重复使用运载火箭结构设计的基本问题。分析了火箭、尤其是发动机结构的载荷特点,提出环境因素作用下的振动疲劳是运载火箭发动机结构的主要失效形式;分析了运载火箭中常见的焊接结构与金属增材制造结构的疲劳问题,总结了运载火箭结构耐久性和可靠性分析的研究现状,对可重复使用运载火箭的耐久性与可靠性设计进行了展望。

Geometry effect on water-evaporation-induced voltage in porous carbon black film

Water-evaporation-induced electricity generation shows great application prospect due to the volt-level voltage induced by natural water evaporation in ambient environment.Increasing investigations have been conducted on water-evaporation-induced electricity in different materials,surface treatments,working mechanisms and wide ranges of practical applications.However,to further enhance the electricity output remains a great challenge.In this study,we fabricated porous carbon black films with isosceles trapezoid shapes to generate water-evaporation-induced electricity,in contrast with the widely used rectangle samples.We found that an isosceles trapezoid film produces two different voltages by inversing the film,because of different flow rates and capillary heights after inversion.The ratio of these voltages varies with the length of longer base when lengths of shorter base and heights are fixed,and the maximum ratio can reach 1.77:1 in our study.This work shows the importance of geometry design in improving the output voltage.

Experimental investigation of three-dimensional mixed-mode fracture of a titanium alloy at room and elevated temperatures

Damage tolerance of titanium alloy structures is very important for the safety of modern aircraft under complex loading and environmental conditions. However, there is no available systematic knowledge about the effect of alloy thickness under mixed-mode loading at elevated temperatures. In the present study, a newly developed fracture experimental technique based on high-temperature moiré interferometry was employed to investigate experimentally I-II mixed-mode fracture in titanium alloy TC11 of various thicknesses at room and elevated temperatures. Compact shear specimens with thickness ranging from 1.8 to 7.1 mm were tested. The effects of temperature, thickness, and loading angle on the load capacity and crack initiation angle were investigated systematically. The TC11 alloy was shown to possess varied fracture performance at elevated tem-perature, and an opposite thickness effect at room temperature. Increasing temperature would enhance the fracture load capacity of thick specimens but reduce the fracture load capacity of thin specimens. Crack initiation angles under I-II mixed-mode loading showed the thickness-temperature coupling effects. These complex effects call for new development in three-dimensional mixed-mode fracture theory and technologies for damage tolerance assessment.

Radial breathing modes of multi-walled carbon nanotubes by an atomic beam-spring model

Based on molecular force fields,a new finite element model is constructed for multi-walled carbon nanotubes where the interlayer interactions and C--C bonds are simulated by the elements of piece-wise linear spring and rectangular cross section beam,respectively.For high computation efficiency and atomic reification,the radial breathing modes of multi-walled carbon nanotubes are studied systemically using this model.The results show the correspondence between carbon nanotube structures and vibrational modes,which provide unequivocal data for the experimental characterization of carbon nanotubes.An empirical relationship of radial breathing modes frequencies with the nanotube radius are also obtained for two-layer carbon nanotubes.

Water models for interfacial water simulations

Interfacial water is of fundamental importance in many technological fields, such as biological processes, chemical reactions and lubrications. A prevalent way to study the structure and dynamics of interfacial water is carrying out molecular dynamics simulations with empirical potential water models. However, discrepant results have been reported due to their different charge geometries and target properties. Here we investigated the interfacial water structures on smooth surfaces of varying hydrophobicity at low temperatures by comprehensive molecular dynamics simulations with the prevailing water models. It is shown that the choice of the water model can significantly change the water structure on the hydrophilic surface, while has a minor effect on the contact angle on a hydrophobic surface. Furthermore, zero-dimensional ice pyramids and one-dimensional icicles were formed under the regulation of external charges injected to the substrate or imposed electric field, respectively. These results offer new insights into the water structures on different surfaces and reasonable choice of parameters in molecular simulations, and the development of water models.

Influence of scanning velocity on the tribology performance of hard disk

The dependence of tribology behavior of hard disk on scanning velocity was investigated by friction force microscopy in both air and vacuum. It is found that the sur-face friction force decreases with increasing scanning velocity in air as well as in vacuum. In vacuum, due to the capillary force disappearing, the adhesive energy decreases signifi-cantly, and the friction force is much smaller than that in air.

Aligned Ni nanowires towards highly stretchable electrode

Easy fabrication of super-stretchable electrodes can pave the way for smart and wearable electronics.Using drop casting unidirectional nickel nanowires with polyurethane matrix,we fabricated a super-stretchable film with high electric conductivity.The as-fabricated film can withstand a 300%tensile strain in the direction perpendicular to nanowires,owing to the transformation of percolating nanowire network from 2D to 3D.In contrast to the decreased film conductivities under large tension in most stretchable electrodes,which usually associate with fractures and irreversible deformations,our film conductivity can increase with the applied strain.This probably benefits from the enhanced electrical contacts between twisted nanowires under tension.The developed super-stretchable film with unprecedented behavior in this work sheds light on the facile fabrication of super-stretchable electrodes with durable performance.

Microstructures and mechanical properties of fiber cells from Echinocactus grusonii cactus spine

Spine is the sharpest and hardest part of many plants, which contains highly aligned fiber cells. Here, we report the micro- structures and mechanical properties as well as their correlation of single spine fiber cells （SFCs） from the cactus Echinocactus grusonii. It is found that the SFCs are 0.32-0.57 mm in length and 4.6-6.0 gm in width, yielding an aspect ratio of 53-124. X-ray diffraction and Fourier transform infrared spectrophotometry show that the spine fiber is mainly made up of cellulose I with a crystallinity index up to -76%. Nanoindentation tests show that a natural spine presents a high modulus of -17 GPa. Removing hemicellulose and lignin from the SFC significantly reduces its modulus to -0.487 GPa, demonstrating the critical role of adhesives hemicellulose and lignin in affecting the mechanical properties of the SFCs. This finding sheds light on de- signing novel bio-inspired high-performance composite nanomaterials with aligned nanofibers, such as using hemicellulose and lignin as adhesive in making carbon nanotube fibers.