不同抚育采伐方式对兴安落叶松林倒木分布格局影响研究

为了解不同抚育采伐方式对倒木分布格局的影响,采用点格局分析法分析不同抚育采伐方式下兴安落叶松原始林、渐伐林和皆伐林内主要树种及不同径级倒木分布格局。结果表明:(1)兴安落叶松原始林、渐伐林、皆伐林中倒木分布格局显著差异,其中原始林随研究尺度增大既有聚集分布也有随机分布,渐伐林均呈显著聚集分布,皆伐林在1~14 m尺度上呈显著聚集分布,其余尺度为随机分布。(2)同原始林相比,渐伐林和皆伐林内兴安落叶松树种倒木均在小尺度呈显著聚集分布,大尺度呈随机分布,而白桦树种倒木均以随机分布为主,只伴有小范围聚集分布。(3)不同抚育采伐方式对小径级倒木分布格局影响显著,对中径级和大径级倒木影响较少。     

倒木基质对长苞铁杉种苗生长及生理特性的影响

以高腐烂(Ⅲ、Ⅳ、Ⅴ)等级的长苞铁杉倒木作为长苞铁杉种子萌发的基质和覆盖物,探讨倒木基质对长苞铁杉种子的萌发和幼苗生长的影响,以期为长苞铁杉的更新提供新的途径和思路。研究中选择直径>20 cm、Ⅲ~Ⅴ腐烂等级的长苞铁杉倒木为试验材料,分不同等级倒木与黄壤土按质量比例2:8、5:5、8:2、1:0、CK（对照,只有黄壤土）探讨倒木作为基质对长苞铁杉种子萌发的影响,以不同等级倒木按照覆盖住种子的不同覆盖厚度2.5、5、7.5、10 mm、CK（对照,只覆盖绵沙）研究倒木覆盖对长苞铁杉种子萌发的影响,结果表明,倒木基质对长苞铁杉种子发芽和幼苗生长均具有一定的促进作用。（1）第Ⅲ等级和第Ⅴ等级的倒木在木:土=5:5处理下种子发芽率与幼苗根长均显著高于其他配比处理。（2）第Ⅳ等级的倒木在木:土=8:2时长苞铁杉发芽率显著高于其他配比处理,在木:土=5:5处理显著影响长苞铁杉幼苗的根长和叶长;各腐烂等级(Ⅲ、Ⅳ、Ⅴ)的倒木在木:土=1:0处理下,长苞铁杉幼苗CAT活性、PPO活性、SOD活性均显著高于对照组(CK);第Ⅴ等级倒木对长苞铁杉幼苗POD活性影响显著。（3）第Ⅲ等级倒木覆盖7.5 mm处理下,长苞铁杉种子发芽率显著高于对照组(CK),覆盖5 mm处理下幼苗根长显著高于对照组(CK);不同腐烂等级(Ⅲ、Ⅳ、Ⅴ)倒木覆盖5 mm处理对长苞铁杉幼苗的叶长有显著影响;第Ⅲ等级倒木覆盖处理下长苞铁杉种子发芽率优于其他等级,但与对照组(CK)无显著差异。     

施秉典型常绿阔叶林森林群落特征

以贵州施秉典型常绿阔叶林1 hm2样地调查数据为基础,从群落种类组成、分布区类型、数量特征、径级结构和空间分布格局5个方面分析该地区常绿阔叶林森林群落特征。结果表明:施秉典型常绿阔叶林共有胸径≧1 cm的木本植物251种2 971株,隶属于47科94属;区系特征明显,科级热带性质较强,属级温带性质较强。施秉典型常绿阔叶林的物种丰富,分布较均匀,优势树种不明显。个体数随植物胸径的增大呈现先增加后减少的规律,径级分布近似于倒"J"型。群落整体呈增长型。从物种的空间分布格局来看,重要值大于10%的13个植物种群和4个主要种群的中、小径木都表现出明显的聚集分布,而4个主要种群的大径木则呈均匀分布。大部分物种随着径级的增加聚集度变小。通过研究以期为更好的认识施秉森林群落,为施秉森林生物多样性保护提供依据。     

The Research of Using BP Neural Network in Prediction of Woods Fire Insurance Grade

The relation between circumfluence index and woods fire.index is described. BP neural network is trained by the known circumfluence index and woods fire index. The restricted feedback and stimulant feed forwardcalculation are to realize self-organizational learningof BP Network.Thereby the nonlinear mapping between circumfluence index and woods fire.index isperformed. With this network, characteristic choice can be carriedout and the accurate prediction of woods fire insurance grade can be given. Its accurate prediction rate is 89%in spring and 82%in summer. The correctnessand feasibilityare illustratedwith the simulate results.     

棉花僵瓣率与品种性状的相关性分析

烂铃严重影响棉花产量和品质,近几年生产上烂铃发生严重。本研究于2009-2012年以僵瓣率作为反映烂铃程度的指标,分析了僵瓣率与棉花9个农艺性状的相关性。结果表明,棉花不同品种间僵瓣率的高低有明显差异,培育低烂铃率品种是可行的;僵瓣率与第一果枝节位呈极显著负相关,与株高呈极显著或显著负相关,与全生育期、出苗至开花日数呈显著负相关趋势,与单株结铃数呈显著正相关趋势。所分析的性状中,对僵瓣率影响最大的为第一果枝节位,其次为单株成铃数和出苗至开花日数,然后为株高和全生育期。研究结果可为选育烂铃率低的棉花品种提供参考依据。     

Damage Detection for Beam and Bridge under Dead Load

We address damage detection based on dead loads in monitoring the health of beams and bridges. We discuss the damage characteristics of statically indeterminate beams under dead loads and analyze monitoring parameters and sensor placement in monitoring. We used an amended genetic algorithm to solve the optimization problem under constrained parameters. Damage in a beam was detected successfully based on dead loads with limited sensor allocations. We present a way to detect damage based on dead loads in bridge health monitoring.     

Compensation of Dead Time Effects Based on the New Switching Strategy

The dead-time inserted into the switching signals of inverters case the dead-time effect of output voltage distortion. The influence of dead-time on output voltage in inverters is analyzed in detail, Then, a new switching strategy, which can provide excellent inverter output voltage distortion correction, is proposed. At last, the experiment results of inverter are presented to demonstrate the practicability and validity of the control strategy.     

蒙古栎枯叶水浸提液对二月兰的化感作用

为探究蒙古栎(Quercus mongolica)林下植被稀少的状况是否为枯叶产生的化感作用,以蒙古栎枯叶为供试材料,二月兰为受体材料,采用培养皿滤纸法研究不同浓度蒙古栎枯叶水浸提液对二月兰种子萌发及幼苗生长的影响。分别采用0.00、0.02、0.04、0.06、0.08和0.10 g/mL浓度的蒙古栎枯叶水浸提液培养二月兰种子,测定发芽率、发芽势、发芽指数、根长及苗长,计算化感综合指数。结果表明,二月兰种子发芽率、发芽势、发芽指数和根长的化感效应指数均为负值,表现为抑制作用,且具有明显的浓度效应。对二月兰苗长的化感效应为“低促高抑”的双浓度效应,在浓度<0.04 g/mL时对幼苗苗长生长有促进作用,当水浸提液浓度≥0.04 g/mL时,对苗长的生长产生抑制作用,且随着浓度的增加,化感作用不断增强,浓度为0.10 g/mL时,根长、苗长的化感指数均为-1,种子仅处于发芽初始状态。反映出蒙古栎枯叶的水浸提液对二月兰具有较强的化感抑制作用。     

体细胞克隆荷斯坦奶牛出生后死亡犊牛内脏器官的组织病理学观察

为探究体细胞克隆荷斯坦奶牛出生后死亡的原因,对新生后死亡的克隆荷斯坦公牛和自然繁殖的荷斯坦公犊的主要组织器官进行比较。通过解剖和石蜡切片-HE(hematoxylin-eosin staining)染色技术,对主要的组织器官结构进行观察和分析。结果表明,新生后死亡的克隆荷斯坦公牛肺部结构清晰;肝脏的肝细胞明显肿大,出现脂肪轻度变性;肾小管上皮细胞出现变性;心肌的肌纤维间空隙增大;骨骼肌纤维间隙明显,空泡变性,这可能导致该克隆牛犊肌肉无力并功能不全;淋巴结皮髓质界限不分明,淋巴小结细胞较稀疏,生发中心不明显,淋巴窦细胞较少;脾脏内红细胞较少,这说明该克隆牛的造血功能可能不完善;胸腺的皮质部分和髓质部分界限不明显,嗜酸性胸腺小体不易辨认,可能发育不全。该克隆公牛免疫器官出现不同程度的发育不全现象较严重,这有可能是其出生后死亡率高的主要原因。     

Comparison of Sugar Beet Cropping Systems with Dead and Living Mulch using a Glyphosate-resistant Hybrid

The aim of this study was to evaluate new options for sugar beet mulch systems, using a glyphosate‐resistant hybrid. In four field trials – conducted in 2002 and 2003 at two sites in a major sugar beet‐growing region in the central Germany – three different mulch systems (straw, non‐winterhardy and winterhardy cover crop) and an alternative seedbed preparation method (rotary band tillage) have been tested in comparison with a control treatment (plough, no mulch, broadcast seedbed preparation) representing the common German practice. In all systems, a set of eight different weed control programmes, including two reference treatments, one with selective conventional herbicides and five exclusively using glyphosate, has been evaluated for efficacy. It could be shown that the integration of winterhardy cover crops into sugar beet mulch systems reduced the risk of nitrogen loss by leaching. The changes in the nitrogen dynamics neither influence the yield nor the technical quality of the sugar beet. The field emergence of sugar beet decreased while using a winterhardy cover crop, but was not altered by the seedbed preparation method. Compared with the conventional broadcast seedbed preparation, the rotary band tillage did reduce the weed density. The lowest weed density was observed in the straw mulch system. It was not possible to control the remaining plants of the winterhardy cover crops completely with selective herbicides. If glyphosate was used until the four‐leaf stage of the sugar beet, a regulation of the winterhardy cover crop was achievable. With glyphosate it was also feasible to control older weeds together with the newly emerging ones with post‐emergence applications only. For most of the mulch systems tested, the sugar beet was very sensitive to weed competition between the four‐ and 10‐leaf stage. If the weeds within the sugar beet rows were controlled during this sensitive period with an early glyphosate band application, the remaining weeds between the rows could be left uncontrolled until the 10‐leaf stage of the sugar beet without any yield loss. Only in the combination of winterhardy cover crop × rotary band seedbed preparation, the weeds and cover crop had to be controlled directly after emergence of the sugar beet.     

Galerkin Approximate Solutions of Displacement Including the Effect of Dead Loads for Two Kinds of Rectangular Plates

Based on the strain energy considering the effect of dead loads, the general form static equilibrium differential equations were formulated by means of the potential energy principle. The approximate solutions of live load or later load displacement including the effect of dead loads for the clamped rectangular plate and the simply supported rectangular plate were generated by the Galerkin method. These formulas are simple and clear, and their physical concepts are explicit. The correctness of these formulas was verified by the finite element method. The dead loads and other factors that influence the effect of dead loads are shown by these formulas. The effect of dead loads on the two different boundary condition rectangular plate were analyzed by these approximate solutions. The effect of dead loads improves the bending stiffness of plate and minimizes the displacement of live loads or later loads. The key physical factors governing the effects of dead loads on plates are the dead load, the ration of span to thickness and boundary condition etc. This effect of dead loads is not negligible, especial in thinner plates or plates with smaller stiffness, more attention should be paid to the effect of dead load in the calculation and analysis for plates.     

水稻叶尖早衰突变体lad的形态、生理分析与基因定位

叶片作为植物的主要光合作用场所,研究其早衰机制对提高作物的经济产量具有非常重要的意义。本研究报道了一个来自EMS诱变优良恢复系缙恢10号的新水稻叶尖早衰突变体lad (leaf apex dead),其叶尖在第5片叶抽出前呈正常状态,当第5叶完全抽出之后前5叶的叶尖变黄并最终枯死;随后的叶子在完全抽出后,叶尖也逐渐变黄并枯死。对该突变体的生理生化分析发现,其叶绿素含量、可溶性蛋白含量明显下降,SOD酶活性异常。其株高、叶长、粒数等也都显著降低。经遗传分析,该突变性状受一对隐性单基因控制,利用分子标记将该基因定位于第11染色体SSR标记SWU11-19和SWU11-5之间,遗传距离为13 cM,并且与SSR标记SWU11-25和SWU11-27共分离。本研究结果为该基因的进一步克隆和功能研究奠定了良好基础。