瓜式粉碎机噪声源的识别分析

本文主要以山东即墨农机厂生产的FFC－23A型扑式粉碎机为例，进行了噪声测试分析，识别噪声源，并对其它型号的爪式粉碎机作了频谱分析，确定了爪式粉碎机主要噪声属空气动力性噪声，且以旋转噪声为主。其次为由主轴不平衡转动引起的各部件振动辐射的固体噪声，证明了爪式粉碎机噪声与动齿、定齿的齿数及它们同时相遇的对数有关，并对空气动力性噪声的产生机理进行了分析，为爪式粉碎机的降噪设计指明了方向。     

爪式粉碎机噪声源的识别分析

本文主要以山东即墨农机厂生产的 FFC—23A 型爪式粉碎机为例,进行了噪声测试分析,识别噪声源,并对其它型号的爪式粉碎机作了频谱分析,确定了爪式粉碎机主要噪声属空气动力性噪声,且以旋转噪声为主。其次为由主轴不平衡转动引起的各部件振动辐射的固体噪声,证明了爪式粉碎机噪声与动齿、定齿的齿数及它们同时相遇的对数有关,并对空气动力性噪声的产生机理进行了分析,为爪式粉碎机的降噪设计指明了方向。     

爪式粉碎机定齿齿数与齿形对噪声的影响

通过对改变FFC-23A型爪式粉碎机定齿盘的内外圈定齿齿数配比及其齿形。对其各工况进行整机噪声测试与分析，提出了同时兼顾降噪与生产率两个性能指标的较佳定齿盘齿形和内外圈定齿齿数组合。     

锤片式粉碎机噪声的测试分析

本文通过对５台锤片式粉碎机（带输料风机）噪声的测试分析，证明了其在空载和额定负载下的主要噪声源都为空气动力性噪声，且属旋转噪声。此旋转噪声由２部分组成，分别由风机叶片旋转和粉碎机锤片旋转产生，且在空载和额定负载２种工况下，二者在整机噪声中所占的主导地位不同。     

齿爪鳃金龟属幼虫近似种触角超微结构研究

对齿爪鳃金龟属幼虫近似种的衣末端感器的超微形态进行了扫描研究。结果表明，触角末感器的数量，类型和排列方式等，种间差异显著，种内相对稳定。触角末端感器是齿爪鳃金龟属近似种分类鉴定的重要特征。     

粉碎机保养小窍门

1．及时检查清理。每天工作结束后应及时清扫机器，检查各部位螺钉有无松动及齿爪、筛子等易损件的磨损情况。     

如何选购饲料粉碎机

根据粉碎原料选择：以粉碎谷物饲料为主的，可选择顶部进料的锤片式粉碎机；以粉碎糠麸谷麦类饲料为主的，可选择爪式粉碎机；若要求通用性好，以粉碎谷物为主，并兼顾饼谷和秸秆，可选择切向进料锤片式粉碎机；粉碎贝壳等矿物饲料，可选用贝壳无筛式粉碎机；若用作预混合饲料的前处理，要求产品粉碎的粒度很细又可根据需要进行调节的，应选用特种无筛式粉碎机等。     

如何选购饲料粉碎机

以粉碎谷物饲料为主的，可选择顶部进料的锤片式粉碎机；以粉碎糠麸谷麦类饲料为主的，可选择爪式粉碎机；若是要求通用性好，如以粉碎谷物为主，兼顾饼谷和秸秆，可选择切向进料锤片式粉碎机；粉碎贝壳等矿物饲料，可选用贝壳无筛式粉碎机；如用作预混合饲料的前处理，要求产品粉碎的粒度很细又可根据需要进行调节的，应选用特种无筛式粉碎机等。     

粉碎机保养技巧

1．及时检查清理 每天工作结束后，应及时清扫机器，检查各部位螺钉有无松动及齿爪、筛子等易损件的磨损情况。     

福建省兰科一新记录种——齿爪齿唇兰

报道了福建省兰科一新纪录种——齿爪齿唇兰（Odontochilus poilanei（Gagnep.） Ormerod）,提供种的简要描述和照片;并分析了该植物分类学地位的变化情况,特别是与齿唇兰属（Odontochilus）和叠鞘兰属（Chamaegastrodia）的关系.基于Ormerod的观点,以福建省齿唇兰属的一新纪录种发表.     

The jupiter-io connection: an alfven engine in space

Much has been learned about the electromagnetic interaction between Jupiter and its satellite Io from in situ observations. Io, in its motion through the Io plasma torus at Jupiter, continuously generates an Alfvén wing that carries two billion kilowatts of power into the jovian ionosphere. Concurrently, Io is acted upon by a J x B force tending to propel it out of the jovian system. The energy source for these processes is the rotation of Jupiter. This unusual planet-satellite coupling serves as an archetype for the interaction of a large moving conductor with a magnetized plasma, a problem of general space and astrophysical interest.     

Saturn's Magnetic Field and Magnetosphere

The Pioneer Saturn vector helium magnetometer has detected a bow shock and magnetopause at Saturn and has provided an accurate characterization of the planetary field. The equatorial surface field is 0.20 gauss, a factor of 3 to 5 times smaller than anticipated on the basis of attempted scalings from Earth and Jupiter. The tilt angle between the magnetic dipole axis and Saturn's rotation axis is < 1 degrees , a surprisingly small value. Spherical harmonic analysis of the measurements shows that the ratio of quadrupole to dipole moments is < 10 percent, indicating that the field is more uniform than those of the Earth or Jupiter and consistent with Saturn having a relatively small core. The field in the outer magnetosphere shows systematic departures from the dipole field, principally a compression of the field near noon and an equatorial orientation associated with a current sheet near dawn. A hydromagnetic wake resulting from the interaction of Titan with the rotating magnetosphere appears to have been observed.     

Productivity Models of Grain Crop Rotation on Gray Forest Soils of the Upper Volga Region

The influence of fertilizers on grain crop rotation productivity and dynamics of ammonium and nitrate nitrogen reserves has been studied in a field experiment on the gray forest soils of the Upper Volga region to develop crop rotation productivity management models. Organic fertilizers have included cattle, chicken, and goose manure and have been applied in various doses. The experimental design has included variants of applying mineral fertilizers (NPK) and their combination with NK and organic fertilizers. It has been established that more than 90% of crop rotation productivity variations accrue to nitrogen in organic and mineral fertilizers; in the light of their interaction, this figure rises to 96.8%. A close power-law or hyperbolical relation has been discovered between the average crop rotation productivity and the average annual nitrate nitrogen reserves in the early crop vegetation. The same kind of relation for this period has been discovered between the first parameter and the ammonium and nitrate nitrogen reserves in the soil solution (mobile nitrogen stock). It is proposed to estimate the mobile nitrogen stock by the mobilization nitrogen pool that depends on the dose of nitrogen in mineral and organic fertilizers.     

Direct measurements of sliding between outer doublet microtubules in swimming sperm flagella

The relative motion of 40-nanometer gold beads bound to the exposed outer doublet microtubules of demembranated sea urchin sperm flagella has been observed and photographed during adenosine triphosphate (ATP)-reactivated swimming. This direct demonstration and measure of sliding displacements between outer doublet microtubules in actively bending flagella verifies the original sliding microtubule model for ciliary bending that was established by electron microscopy of fixed cilia and provides a new, functional measure for the diameter of the flagellar axoneme of 132 +/- 8 nanometers.     

福建省项目投资促进税收增长的分析与预测

2003年福建省委省政府作出实施项目带动战略重大举措，围绕着促进固定资产投资增长，积极推进投资结构的调整，坚持以项目带动战略培育税源，促进经济增长。本文通过固定资产投资与税收增长的互动关系的理论分析，建立计量经济模型，来分析固定资产投资项目带动战略对增加税收的影响，从而为进一步深化项目带动战略，促进税收增长，提出相应的政策建议。     

双林分轮伐期分析

在Ric.Hartman单一林分最优轮伐期模型的基础上,考虑双林分的最优轮伐期问题。森林资源有其独特性,同时具有木材商品价值与美学价值,主要以林分之间的美学价值相互影响为基础分析双林分最优轮伐期,与单林分最优轮伐期的不同在于,双林分林区的砍伐具有外部性,因此有必要对双林分的砍伐进行分析。     

压力磨盘式薏苡脱壳装置的设计与试验

为提高薏苡脱壳质量,运用柔性剪切揉搓脱壳原理,设计了一种压力磨盘式薏苡脱壳装置。装置主要由进料搅龙、动磨盘、压力磨盘和压力调节装置等部件组成。工作时,薏苡随进料搅龙进入脱壳空间,依靠两磨盘之间的压力和摩擦力对薏苡进行揉搓脱壳,当压力磨盘受力大于薏仁破碎力时被顶起,以增大脱壳间隙,保护薏仁。对薏苡在导流区、破壳区和分离区的受力进行分析,确定影响薏苡脱壳质量的主要因素为薏苡含水率、脱壳转速、脱壳间隙和预紧力。以脱净率、破损率为试验指标,通过单因素试验确定薏苡脱壳装置的最佳参数范围;基于单因素试验结果,选取含水率为7%的薏苡,以脱壳装置的转速、脱壳间隙和预紧力为试验因素,脱净率和破损率为响应指标,进行三因素二次回归正交旋转组合试验,结果影响薏苡脱净率的主次因素依次为预紧力、脱壳间隙、脱壳转速,影响薏苡破损率的主次因素依次为脱壳间隙、预紧力、脱壳转速;基于响应曲面法对回归模型进行多目标优化,优选出脱壳装置的最佳作业参数组合为脱壳转速513.625 r/min、脱壳间隙2.061 mm、预紧力119.628 N,薏苡脱净率为91.731%、破损率为9.612%。将优化参数圆整,对薏苡进行连续脱壳作业,测得薏苡脱净率为91.12%,破损率为8.93%,可满足实际生产要求。