为揭示毛竹株内、株间基本密度变异规律，测定了不同竹龄、不同高度、不同径向部位毛竹的基本密度，并进行了方差检验和多重比较q检验；对测定的结果回归分析，得出基本密度-竹龄关系的回归方程。结果表明：毛竹基本密度株内径向变化规律为竹青基本密度最大、竹黄基本密度次之、竹肉基本密度最小；株内纵向变化规律，基本密度自下而上逐渐增大。同龄毛竹株间基本密度的变异相对较小，仅有1年生、4年生、5年生的竹黄基本密度差异极显著，1年生竹肉的基本密度差异极显著，6年生竹青的基本密度差异极显著。不同竹龄毛竹基本密度的变化规律为1年生的基本密度最低、2年生的基本密度迅速增长、3年生的基本密度略有降低，之后小幅波动并呈上升趋势；至7年生为止，总体上基本密度呈逐年增长的趋势。

The experiment was conducted to study the basic densities with different ages, different height and different radial po-sitionsto reveal the variation regularities ofP hyllotachys pubescens within a bamboo and among bamboos and investigate the variance test and multiple comparison q test.By regression analysis, the regression equations of the relationship were ob-tained between densities and ages.The radial variation of outer moso bamboo density is maximum, and the inner is mini-mum.The longitudinal variation of density increases gradually from bottom to top.The variation of basic densities at the same age was relatively small except the inner bamboo at one, four and five years, the middle bamboo at one year and the outer bamboo at six years.Variation rule of different age moso bamboo density is that:the basic density of one year is min-imum, that of two years is in rapid growth, that of three years reduces slightly, there is a slight fluctuation with the rising trend, and until the se

试验以桂单162为供试材料,采用2因素裂区设计,密度为主处理,行距为副处理,研究4个种植密度下4种行距配置方式对玉米产量及其构成因素的影响。结果表明:密度、行距及密度与行距互作对玉米出籽率的影响不显著;密度、密度与行距互作对玉米结实长度影响达到极显著水平,随着密度加大结实长度越短,不同密度与不同行距配置才能对结实长度起到最大的影响作用;种植密度对穗粗影响达到显著水平,穗粗随着种植密度加大而变小;密度、行距及密度与行距互作对产量的影响达到极显著水平,4种种植行距下4 000株/667m2产量最高,4个密度下60 cm单行单株种植产量最高,桂单162以4 500株/667m2,60 cm单行单株种植产量最高。

M aize variety ofG uidan 162 w as used as experim entm aterials.A tw o-factor splitplotexperim ent,density as m ain processing, row spacing as deputy processing,w as conducted to explore the effectof four planting densities and four row spacings on m aize yield and yield com ponents .The results show ed thatpercentof bearing kernelw as notsignificantly influenced by density,row spacing, interaction betw een density and row spacing;Length ofbearing kernelw as very significantly influenced by density,interaction betw een density and row spacing,itw as increased w ith the increase ofdensity;Eardiam eterw as significantly influenced by density,itw as decreased w ith the increase ofdensity;M aize yield w as very significantly influenced by density,row spacing, interaction betw een density and row spacing,under four row spacing conditions the highestyield w as 4000 plants/667m 2,under four densities conditions the highestyield w as 60 cm row spacing, density and row spacing w ere 4

为探讨林分密度对林地土壤水分物理性质的影响，以火地塘林区不同林分密度范围（1000～2000、2000～3000、3000～4000株/hm2）的松栎混交林（中龄林）为研究对象，各设置2～3块标准地，对土壤进行分层采样，室内测定土壤的含水率、密度、孔隙度和有机质质量分数。结果表明：在不同林分密度松栎混交林中，土壤含水率表现为低密度林分＞中密度林分＞高密度林分；土壤密度是中密度林分较小，土壤较疏松，低密度和高密度林分土壤密度较大；总孔隙度和有机质质量分数的大小均表现为中密度林分＞高密度林分＞低密度林分。可见，在松栎混交林中，中密度林地土壤理化特性优于过密或过疏的林分，其土壤密度较低，土壤较疏松，孔隙度和有机质质量分数较都较大。因此，中密度林地有利于改良土壤的理化特性，提高土壤肥力。研究揭示：林分密度与土壤水分理化性质的关系密切。在火地塘林区松栎混交林的经营管理过程中，可以通过人为措施适当调整林分密度以改善林地土壤水分理化状况，提高土壤肥力水平，促进林木健康生长。

An experiment was conducted to discuss the effects of stand density on physical and chemical properties of soil mois-ture.We took oak-pine mixed forest (middle-aged plantation) of different stand densities (1 000-2 000, 2 000-3 000, 3 000-4 000 plants/hm2 ) at Huoditang forest region in Qinling Mountain and set 2-3 standard plots for stratified soil sam-ple, the soil water content, density, porosity and the contents of organic matter.Under different densities of oak-pine mixed forest, the soil water content is in the order of low density stand>moderate density stand>high density stand under different densities of oak-pine mixedforest .The moderate density stand has lower bulk density than that of low density stand and high density stand.The soil for moderate density stand is softer.The order of total porosity and content of organ-ic matter are moderate density stand>high density stand>low density stand.In the oak-pine mixed forest with moderate stand density, the soil bulkdensity is lo

用模拟药和可退模开合弹对不同分步压装装药工艺参数进行实验，并对装药密度和轴径向密度分布进行检测，分析分步压装工艺参数变化对最终装药密度和密度分布的影响。试验结果表明：随着螺杆直径的增大，周边和平均装药密度均呈上升的趋势；装药过程中初始压力越高，越有利于提高装药密度和密度分布，当压力达到一定值后，装药密度趋于一致；螺杆距弹体底部间距越小，底部越容易压实，密度越高；螺杆每次带入的进料量越少，压制次数越多，密度均匀性越高。该研究为加快分步压装装药工艺的推广应用打下了基础。

Analog explosive and unmoulded shot were employed to experiment the different parameters, and detection density distribution of charges and axes radial, analyzed the effect of step-press-loading technological parameter for finally charge density and density distribution. The results show that, the effects on charge density and density distribution of step-press-loading charge technology are observed obviously. The average charge densities are enhanced with the increasing screw diameters, charge quality and density distributions are also improved with the increasing pressures. When the bottom gap of shot decreases, shot bottom can be pressed more easily, and the charge density can be improved at the same time. The press frequency and density uniformity can be promoted with the decreasing charge quantity. This research will promote the use of the step-press-loading charges technological.

煤的视相对密度是煤炭资源储量估算的一个重要参数。影响煤的视相对密度因素很多,其中煤样粒度对煤的视相对密度结果影响大。根据块煤和小颗粒煤测定煤的视相对密度结果分析,认为小颗粒煤测定煤的视相对密度结果重复性好,而块煤重复性较差,块煤测定视相对密度结果值普遍小于小颗粒煤,建议采用小颗粒煤行标法;对于某些煤样过于破碎或易泥化,取不到具有代表意义的3~6mm粒级的煤样,或出现真密度小于视密度的现象时,可利用真相对密度值或实测视密度样之灰分值进行换算处理,提供一个合适的视密度值来进行煤炭储量的估算,使煤炭储量估算值更接近于真值。

The apparent relative density of coal is a major parameter in coal resources estimation. Many factors impact apparent relative density measurement, while the granularity of coal sample has larger impact on the result. Based on analysis of results from lump coal and granular coal, considered that results from granular coal have good repetitiveness, while from lump coal poorer, generally less than from granular coal. Thus measuring method from granular coal industry standard is proposed. For some coal samples excessively cracked or east to degradation in water can take 3~6mm sized coal sample with representative significance. If true density less than ap-parent density appearing, carry out conversion of true relative density value or measured apparent density sample ash content value, provide an appropriate apparent density value as possible to estimate coal reserves, making the estimation closer to the true value.