白刺叶片形态变化对叶片δ13C的影响

选取磴口、民勤唐古特白刺,敦煌东湖附近洪积扇中部、底部生长的泡泡刺为研究对象,通过叶片扫描与Image-Pro Plus6.0图像处理软件分析获得叶片形态参数(长、宽、周长和面积),应用同位素分析获得叶片δ13C值。结果表明:随着水分有效性的增加,白刺叶片面积具有增加趋势,叶片面积在增加过程中,叶片长、宽增幅具有非同步性;相同叶片宽度,生长于水分条件较好地区的唐古特白刺和泡泡刺叶片更长。虽然磴口、民勤及敦煌东湖附近洪积扇中部、底部水分环境存在较大的差异,但生长于这些区域的唐古特白刺及泡泡刺叶片δ13C值的差异不显著(P>0.05)。叶片周长/面积比是连接叶片形态变化与植物水分生理的重要因子;白刺叶面积增加过程中,叶片长度的优先增加有利于减缓周长/面积比的下降速率,从而使白刺保持较高的水分利用效率。     

烤烟叶片田间生长过程中叶片干鲜比值的变化

田间状况下对烤烟下、中、上三个部位叶片生长发育过程中叶片干鲜比值的变化进行了研究。结果表明：在烤烟田间叶片生长发育过程中，随着烟叶部位的上升，叶片干鲜比值表现为随之增加的变化规律，不同烟叶部位之间叶片干鲜比值的差异显著，而不同叶龄之间叶片干鲜比值的差异不显著。随着叶龄的增大，三个烟叶部位叶片干鲜比值的变化不尽一致，下部叶表现出随之缓慢降低的变化规律，中部叶表现为“锯齿”型的变化，上部叶表现为随之逐渐增加的变化规律。相关分析表明，叶龄与叶片干鲜比值之间呈不显著正相关。     

叶片位置和切除方式对巨细桉DH201 2再生的影响

以巨细桉无性系DH201-2叶片为材料进行植株再生研究,揭示叶片位置和切除方式对愈伤组织诱导和植株再生的影响,结果表明:叶片位置对叶片培养死亡率与叶片植株再生率、叶片植株再生芽数影响显著,对愈伤产生率基本没影响。以组培生根苗第1～6片叶作外植体进行愈伤培养与植株再生培养效果较好,以第1～2片叶作外植体效果最佳,第7～8片叶不宜作为外植体培养;拉下或剪下全叶两种方式,植株再生率与再生芽数较高,全叶剪除1/3叶尖方式效果最佳,能有效加速叶片的愈伤生长及植株分化,提高叶片植株再生率及再生芽数。全叶剪除叶柄及1/3叶尖方式效果最差,植株再生率、再生芽数效果最低。培养50 d,愈伤植株再生率及再生芽数达到高峰期。     

紫丁香叶片面积测量方法的研究

选取５个地点典型紫丁香叶片为材料，用回归相关和乘常数法研究了紫丁香叶片长、宽与叶片面积的关系。结果表明：叶片面积与叶片长、宽的相关系数均达到１％祖显著水平，与叶片长、宽的直线关系（ｙ＝ａ＋ｂｘ）及与叶片长、宽的两种曲线关系（ｙ＝ａｘ￣ｂ、ｙ＝ａ＋ｂｌｏｇｘ）成立；用它们去估测叶片面积，能得到极相似的结果。用乘常数法估测叶面积简便、易行。两种方法的估测值与实测值之间差异均不显著，都具有不需离体、准确、快速及易于推广等优点。     

板栗叶片衰老初探

在板栗离体叶片衰老过程中，叶绿素、蛋白质含量及超氧物歧化酶活性不断下降，丙二醛含量迅速上升。高温可加速板栗叶片的衰老，而营养液则延缓其衰老进程。     

11个黑杨无性系叶片性状变异研究

对11个黑杨无性系的叶片性状的变异进行了研究，并通过回归方程的计算，得出了各无性系叶面积与长宽乘积的线性模拟方程。研究结果表明：在叶片形成速度上各无性系并无大的差异，但由于叶面积及叶干重存在较大差异，在单位叶面积的形成速度上存在着较大差异。     

白杨杂种无性系叶片保水力研究

对毛白杨双杂交无性系ｌａ生苗木叶片解剖构造、离体叶片失水率、组织细胞质膜透性进行了测定比较。用这３项指标对各无性系叶片保水力进行了综合评判，并对各指标进行了评价。     

毛豹皮樟叶片总DNA的提取

在参考其它植物DNA提取方法的基础上，结合毛豹皮樟富含还原糖及多酚类物质的特殊性，用CTAB法和改良SDS法对毛豹皮樟的叶片进行了DNA提取试验，结果表明：改良SDS法是一种适合于毛豹皮樟叶片DNA提取的较理想的快速途径。     

竹基风力发电机叶片技术及其在竹材工业化中的应用前景

竹子生长快、强度高、分布广泛、绿色环保。但在全球范围内对竹子的高附加值应用还处于相对初级阶段,而且工业自动化水平较低。竹基复合材料风力发电机叶片代表了目前竹材工业化应用的较高技术水平,该产品通过解决竹材离散性大、易开裂变形、与金属材料连接的稳定性差等难题,为竹材应用于更多工业级产品提供了可能。文章从竹材离散性控制、疲劳性能测试、连接设计、一体化结构设计以及质量控制等方面阐述了竹基复合材料风力发电机叶片技术研发中的重点与难点,期望这些技术能够为竹材的工业化应用带来启发和借鉴。     

不同产地文冠果叶片黄酮类成分差异

【目的】比较分析不同产地文冠果叶片黄酮类成分的差异，为挖掘黄酮类成分含量高的优良单株及茶用型文冠果种质资源提供科学参考。【方法】建立了液相色谱串联质谱法检测文冠果叶片黄酮类成分的技术体系，并利用方差分析、相关分析和主成分分析等方法对来自山东潍坊、宁夏吴忠和辽宁大连的共495株文冠果样树叶片的10种黄酮类成分进行了比较分析。【结果】山东潍坊文冠果叶片黄酮类成分总含量为682.135～2 935.579μg·g^-1；宁夏吴忠文冠果叶片黄酮类成分总含量为267.897～4 899.386μg·g^-1；辽宁大连文冠果叶片黄酮类成分总含量为703.787～2 878.085μg·g^-1。三产地黄酮类成分总含量高低顺序为：山东潍坊(1 451.666μg·g^-1)>辽宁大连(1 425.822μg·g^-1)>宁夏吴忠(1 235.374μg·g^-1)。不同产地文冠果叶片各黄酮类成分的含量及总含量均存在显著差异(P <0.05)，其中，山东潍坊文冠果叶...     

裁板锯偏转机构运动关系的反求设计与仿真

针对裁板锯锯片偏转系统运动关系复杂不易于单片机编程的问题,提出了应用反求设计开发模式求出连杆与丝杠系统的伸长量X和与之对应锯片偏转角度θ之间的函数关系。从采用Lagrange插值仿真得到的系统仿真曲线可知,四次多项式传递函数可以满足运动关系的精度要求,采用Matlab仿真最终确定二者之间的关系为一次函数。通过实验得出当偏转角为10°和35°时计算得到的直线误差最小,据此设计的裁板锯MJ6130Z已经批量生产。

Abstract：

In view of the problem that complicated motion relationship of the blade deflection system of board cutting saws makes MPU programming difficult,the function relation between the extension volume of the connecting rod and screw rod system and the correspo     

MR5412型圆锯片气焊加热适张度机工艺与设备的研究

加热适张度是利用氧一乙炔焰,将锯身的一定部位加热,使该部在冷却收缩中产生同辊压张力一样的变形,从而获得适张度。圆锯片气焊加热适张度机配有带锯夹锯装置,可用于圆、带锯的加热适张度及辊压处理,实现了一机多用。经该机修整的锯片,具有作业时间短、适张度均匀且不易消失,锯末端加热部分不易变形,厚度均匀,锯切质量高等优点。     

Research on the effect of yield strength of circular saw blade on roll tensioning process

In this paper, a 2-D and 3-D finite element model of roll tensioning process of circular saw blade were established by Static/General module of ABAQUS software based on finite element method. The rolling force and tensioning stress distribution of circular saw blade were calculated by these two models which were proved to be true and reliable. The effects of yield strength of circular saw blade on tensioning stress distribution and rolling force were studied. The research achievements showed that a circular saw blade made with high yield strength obtained a higher tangential compressive stress and radial compressive stress in the rolled region during roll tensioning process, which has both advantages and disadvantages for the stability of the saw blade. Besides, a circular saw blade made with high yield strength also put forward higher requirements for roll tensioning equipment because of the large rolling force during roll tensioning process.     

Experimental studies on band saw blade vibration

Summary The band saw blade vibration under non-moving and moving conditions has been experimentally studied for band saw blades unfitted with saw tension and back crown, fitted only with saw tension, and only with back crown. The lateral natural frequency of a band saw blade was found to decrease by fitting saw tension in a saw blade, but there was little or no effect for blades having only back crown. The torsional natural frequency of a band saw blade increased by fitting saw tension in a saw blade, but again there was little or no effect of fitting back crown in a blade. The lateral natural frequency decreased by tilting the upper wheel for the band saw blades investigated. On the contrary, when the upper wheel was tilted the torsional natural frequency increased for an untensioned blade with no back crown, and blades fitted only with back crown, however, there was little or no effect for a band saw blade fitted only with tension. The lateral and torsional natural frequencies significantly affected the over all self-excited displacement vibration of band saw blades. However, the displacement vibration due to the frequency of the number of wheel rotation affected significantly the over all self-excited displacement vibration of a band saw blade fitted with excessive back crown.The authors wish to express their appreciation to Dr. F. E. Dickinson, Univ. of California, Berkeley, Calif., for an excellent job of revising the grammar and his valuable suggestions. This investigation was supported in part by Grants in Aid for Scientific Research from the Ministry of Education, JapanMembers of the Faculty of Forestry, Shimane Univ., Matsue, JapanMember of Shimane Prefecture Forestry Experiment Station, Shimane, Japan     

扭曲叶片的测量与强度校核

利用三维坐标仪 ,对一空间叶片进行了定位测量 ,计算出各截面的主要参数 ,根据叶片的受力特点 ,对叶片进行强度校核 ,并对结果进行了理论分析     

带锯机锯轮转速、锯条摆动与锯解精度的试验研究

基于对木工带锯机加工特性的研究需要,本文在MJ397型高速木工带锯机的锯条张紧力和进给速度恒定的情况下,通过实测锯机工作台和锯条结构系统的固有频率、同条件下锯割杉木试材时的锯条横向摆动量、变频器调节锯轮转速和锯材表面粗糙度等,分析锯轮转速、锯条横向摆动量与锯解精度的关系,为优化国产带锯机锯割稳定性等设计工作提供依据.     

Knife slicing of wood across the grain

Summary This paper investigates a method for slicing thick pieces of wood across the grain using a sharp steel knife, and it demonstrates the effectiveness of the knife slicing process at an experimental level. In order to highlight the key parameters facilitating or hindering the thick slicing process, several factors affecting the cutting forces and the cut surface quality have been studied; the blade geometry, the effect of friction, the cutting speed, the boundary load constraints and the wood moisture content. The results indicate that a large proportion of the cutting force may be related to the wedging action of the blade in the wood. Therefore, significant reductions in the cutting energy can be achieved by optimising the blade shape. A simple homogeneous strain model has been developed which quantifies the cutting forces in terms of the blade angle and the blade surface friction. The results from this theoretical model are compared with the experimental findings and discussed in relation to methods for improving the cutting technique.This work was funded by the Foundation for Research Science and Technology. This support is gratefully acknowledged     

油橄榄叶片中黄酮的提取工艺探究

通过优选确立2年生油橄榄弗奥叶片中黄酮的最佳振荡加热提取条件，以其总黄酮含量为指标，用正交分析法对叶片细度、提取时间、提取剂乙醇的浓度3个因素对试验结果的显著性进行分析，优选研究得到叶片细度对该方法提取黄酮影响不显著，而提取时间和乙醇浓度都较显著最佳提取时间为6h，提取剂乙醇的最佳浓度为75％。结果表明油橄榄叶片中黄酮的最佳振荡加热提取工艺为A1B1C1，即叶片细度为100目、提取时间为6h、乙醇浓度为75％。     

铜对圆锯片热应力的影响与研究

通过锯切木材试验,分别对锯身槽上嵌铜和不嵌铜设计的同条件下木工圆锯片,进行定点温度、横向摆动量和噪声参数的测量;并结合有限元热应力场分布与计算,以及铜材理化试验分析等手段,得出其嵌铜锯片消除热应力性能好,振声性能较高,锯片使用寿命延长等结论,并提出减振降噪的措施与建议,为优化圆锯片的设计工作提供参考依据。     

BX4612/5刨片机刀片支承座加工工艺改进

对刨片机刀片支承座加工工艺流程进行了改进，以保证加工基准的统一。改进设计的专用工装提高了刀片支承座的加工精度和生产效率，使BX4612/5环式刨片机能真正做到以产保销。