灾害蝗虫附着系统爪尖的剪切强度测算

蝗虫爪尖能够形成用于稳固附着的机械锁合,抑制蝗虫在捕集滑板表面的滑移行为。为获取用于蝗虫捕集滑板研制的爪尖强度信息,利用自行设计的昆虫微力测试系统测试了蝗虫前足、中足、后足爪尖的剪切力;采用扫描电镜(scanning electron microscopy,SEM)分析了蝗虫爪尖及其断裂面的微形貌结构与几何特征,计算了爪尖断裂面的截面积,并据此测算了蝗虫爪尖的剪切强度。结果表明爪尖的剪切力介于197.4~243.6 mN,其中前足爪尖的剪切力最大,后足居中,中足最小;爪尖断裂面表现出层状的复合结构且具有显著不同的截面积(10 847.6~13 908.5μm2);测算结果表明蝗虫爪尖的剪切强度介于14.2~22.5 MPa。该研究可为研制具有良好滑移功能蝗虫捕集滑板提供参考,并可促进灾害蝗虫光电诱导滑移捕集技术的发展。     

气扰刺激与波谱光源耦合作用下蝗虫的诱导捕集试验

灾害蝗虫光电诱导捕集技术中,致使蝗虫产生良好趋光效率的诱导光源是获取该技术高效应用的关键。为给诱导光源的研制提供最优设计参数,利用自行设计的发光二极管(light emitting diode,LED)阵列波谱光源与光电诱导蝗虫滑移捕集机分别进行了蝗虫趋光行为的对比试验和诱导捕集试验。结果表明:与其他诱导光源相比较,蓝色(465 nm)波谱光源和白色(395~720 nm)波谱光源均能促使蝗虫产生较为明确的趋向选择行为且具有相对较高的趋向运动速度,最终诱使较多的蝗虫集聚于诱导光源区域;气扰刺激能够激发处于栖息状态蝗虫的生理活性,促使蝗虫对波谱光源产生较强的趋向行为并表现出较高的趋向运动速度。气扰刺激与波谱光源的耦合作用可使蝗虫的趋光行为同时具有明确的方向选择性、较强的趋向运动持续性和较高的趋向运动速度,能够显著提高波谱光源对灾害蝗虫的诱导率,并能提高光电诱导蝗虫滑移捕集机对灾害蝗虫的捕集效率和捕集总量。研究结果为光电诱导蝗虫捕集技术中诱导光源的研制提供了设计参数方面的参考。     

18CrMnTi钢表面激光微造型的仿生工艺

为了探讨激光微造型表面仿生非光滑效应中粗糙度提高的工艺,运用SEM扫描电镜和图像处理技术提取荷叶表面微纳米形貌特征,在犁铧钢(18CrMnTi)表面进行激光微造型表面仿生正交试验研究。研究表明,图像处理中Sobel边缘算法有效地提取了SEM图片表面微纳米形貌层次特征,图像阈值取255时,提取表面形貌特征最多,犁铧钢仿生表面基本上再现了荷叶表面形貌;激光表面微造型极显著因素的主次关系是阈值>打标次数>电流强度,表面仿生最优值处的微造型粗糙度参数,即表面轮廓算术平均偏差(Ra)、微观不平度十点高度(Rz)和最大轮廓高度(Ry)提高的倍数分别为86.11、232.29和116.06。研究结果为激光微造型表面仿生多层次提取表面形貌信息和提高表面粗糙度工艺提供参考。     

气吸式蝗虫捕集技术的发展与蝗虫的养殖利用

蝗虫营养成分含量高，用途广泛，是一种很好的昆虫资源，在食用、药用、饲用等方面均有利用价值；气吸式蝗虫捕集技术在蝗虫灾害的防治和蝗虫资源的无害化捕集利用中起到重要的作用，通过对4种不同结构形式的蝗虫吸捕机的结构形式和作业特点的对比分析，找出了各自的优点和不足之处并提出了一些改进的建议，分析了每种机型所适用的作业范围。随着对蝗虫资源需求量的增大，蝗虫的网棚养殖技术也逐渐兴起、养殖规模不断扩大，通过对上述蝗虫吸捕机的分析研究，为研制一种适合于网棚内使用的小型、轻便的蝗虫吸捕机提供了参考依据。     

山东省农业仿生应用工程技术研究中心

山东省农业仿生应用工程技术研究中心(简称仿生中心)于1998年由山东省科学技术委员会批准成立并命名,主任孟昭礼教授。该中心主要从事仿生农药的研制工作。仿生农药就是以生物体内具有生物活性物质的化学结构为先导化合物(模板),采用有关化工原料模拟合成的农药。它们具有高效、经济、安全的特点,是今后农     

挖掘机獾爪趾仿生斗齿提高其入土性能仿真与试验

为解决挖掘机斗齿入土阻力大,易断裂的问题,该文利用Handyscan700扫描仪获取獾右前爪中趾表面的三维点云,提取獾爪趾的侧面轮廓曲线,并进行拟合得到曲线方程,将获取的曲线方程运用到斗齿的设计中,利用三维软件建立斗齿模型。运用有限元分析软件对仿生斗齿和80型斗齿的力学性能和切土过程进行数值模拟,对比分析了力学性能的差异以及能量损耗与切土深度的关系。采用快速成型加工技术加工出了仿生斗齿与80型斗齿试样。利用电子万能试验机对2种试样进行了楔土试验,测定了楔入阻力与楔入深度的关系。结果表明：在施加相同载荷的情况下,仿生斗齿所产生的最大等效应力小于80型斗齿的,破坏的可能性小,比较安全;当斗齿的入土深度相同时,仿生斗齿的消耗的能量总小于80型斗齿;在同样条件下,仿生斗齿的楔入阻力较80型斗齿低11.9%～12.6%。该文以獾爪趾为仿生原型设计的挖掘机斗齿不仅解决了工程中遇到的问题,还为减阻部件的开发提供了新思路,具有重要的参考价值。     

基于螺旋贝壳仿生的发动机增压器涡轮蜗壳设计提升涡轮性能

增压器蜗壳性能直接影响增压器整体效率和性能。通过降低蜗壳内腔流动阻力、减少蜗壳能量损失对提高增压器效率和性能具有重要意义。海洋螺旋形贝壳在进化过程中形成了减少流体阻力、降低运动过程中流体能量损耗的结构特征。该文以螺旋贝壳为仿生原型,通过逆向工程技术获取贝壳内腔数据,在几何分析的基础上提取内腔截面部分数据作为仿生蜗壳设计原始数据,并完成数学建模。通过数据优化得到增压器涡轮蜗壳仿生设计截面曲线,实现蜗壳仿生曲面设计。建立原型增压器和仿生增压器计算模型,在原型增压器仿真模型与台架试验吻合较好的条件下,采用流体力学软件对原型及仿生优化增压器涡轮效率、流通特性及蜗壳内流态等性能进行仿真分析。结果表明,涡轮流通能力不变情况下,仿生蜗壳使涡轮效率提升3%,最大可提升5%以上;流场分析结果表明,仿生优化蜗壳减小蜗壳壁面附近的流动损失和流道内气流摩擦,壳内流动平稳均匀,无旋流,是涡轮效率明显提高的根源。本文所采用的方法对增压器涡轮性能的提升显著,可以为汽车和农业机械涡轮增压系统设计和优化提供参考和借鉴。     

DTC类重金属捕集剂对猪场废水中Cu、Zn的去除试验研究

通过黄原酸化反应将二硫代氨基甲酸(DTC)基团引入至壳聚糖,制备DTC类重金属捕集剂,用以去除猪场废水Cu、Zn。结果表明,DTC类重金属捕集剂对Cu、Zn的捕集性能受废水初始p H值和捕集剂投加量的影响,p H值有一个适宜范围,即p H 3.0~5.0;随着捕集剂投加量的增加,去除效果逐渐增加,但增加速率逐渐减缓。捕集剂性能受进水Cu、Zn浓度以及废水温度的干扰不很明显。在废水p H值5.0,捕集剂投加量2.0 g·L-1(废水),初始Cu、Zn浓度25~200 mg·L-1时,捕集剂对Cu、Zn的去除率可达到99%以上,且处理后Cu、Zn浓度低于污水综合排放标准(GB 8978—1996)一级标准限值规定。DTC类重金属捕集剂对Cu、Zn的等温吸附特征可用Langmuir方程进行拟合,其吸附平衡时间约为20 min左右。     

基于人工倾斜摄影测量的微地形三维建模方法研究

耕作坡面微地形是地表径流和土壤侵蚀的重要场所,建立其高精度三维数值模型是定量研究土壤侵蚀过程的基础。针对现有接触式和非接触式测量方法得到的三维模型不能完全真实地反映微地形特征的缺陷,提出了一种获取坡面微地形高精度三维模型的人工倾斜摄影测量方法(ATPM),并对建模精度进行了评价。结果表明,采用ATPM方法建立的地表三维模型精度高,空间各点的平面中误差和高程中误差分别为±1.9 mm和±2.6 mm,能很好地反映微地形的细微特征,可为定量研究土壤侵蚀过程提供较高精度的数据支持。     

基于功能化介孔二氧化硅的贻贝中磷脂选择性纯化研究

为制备高纯度海洋源磷脂,本研究利用微乳液法制备介孔二氧化硅(KCC-1)微球,并基于水蒸气内部水解法对其进行功能化修饰,分别合成二氧化钛/KCC-1(TiO₂/KCC-1)和氧化石墨烯/KCC-1(GO KCC-1)复合材料,再通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、原子力显微镜(AFM)等技术表征形貌结构,而后制成固相微萃取(SPE)柱。以贻贝为原料,分别采用TiO₂/KCC-1 SPE和GO/KCC-1SPE法纯化磷脂,以富集因子(EF)作为指标评价其性能,达到制备高纯度磷脂的目的。结果表明,合成的KCC-1微球直径为250～400 nm,形貌良好、大小均一、比表面积较大,且经功能化修饰,成功合成了TiO₂/KCC-1和GO/KCC-1填料。对比分析可知,■,说明TiO₂/KCC-1 SPE法纯化磷脂的作用效果更优。通过该方法制备的磷脂纯度高达93.57%。本研究结果为高纯度海洋源磷脂的制备提供了技术支撑。     

冰温贮藏期间淀粉添加对水滑肉品质的影响

水滑肉是我国传统的菜肴,具有爽滑细嫩、鲜香无比的特点。为了探究水滑肉淀粉外壳变化对水滑肉品质的影响,以质构、剪切力、水分含量、回生程度、淀粉热力学特性等为评价指标,研究了在冰温贮藏期间水滑肉品质的变化情况。结果表明：与水煮肉进行对照,在冰温贮藏期间淀粉的添加显著抑制了水滑肉的硬度、咀嚼性及剪切力的增加;水滑肉在贮藏期品质指标劣化,但感官得分优于对照组。在冰温贮藏期间,水滑肉外壳的水分含量、糊化焓值及R_1047/1022依次增加了7.29%、327.42%、5.17%,增长幅度均低于淀粉组 (P＜0.05);肉的存在显著减缓了水滑肉淀粉外壳的回生(P＜0.05)。在冰温贮藏条件下,淀粉外壳的回生与水滑肉的质构指标呈现显著正相关(P＜0.05),即淀粉外壳的回生会劣化水滑肉的硬度、咀嚼性和剪切力。冰温条件下,肉中水分向淀粉外壳转移可能会延缓淀粉外壳的回生,从而延缓其品质劣化;冰温贮藏第8 天可能为水滑肉品质变化的关键点。研究结果可为水滑肉预制菜肴品质研究提供参考。     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.     

Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater

Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells.     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.