筛分法和激光粒度法联合测定陆源碎屑岩粒度

用筛分法和激光粒度法联合测定陆源碎屑岩粒度,对激光粒度法的分析数据进行了校正,以保证两种方法的分析数据配套衔接.通过对比不同地质年代沉积岩的岩心校正前后概率累积频率曲线,校正后的曲线能更好地表征碎屑岩粒度的分布.对影响马尔文Mastersizer 2000激光粒度仪背景测量的进样器搅拌转速A、泵速B、超声强度C三个因子...     

激光粒度法与筛分法测量洗煤泥粒度分布对比

为了寻找能恰当描述高浓度黏稠物料粒度分布的方法,以洗煤泥为代表物料,通过筛分法与激光粒度法对比实验,研究激光粒度分析技术法应用于浓密膏体的可行性。结果表明,激光粒度法对于小粒径范围的测量更敏感,较筛分法更适于洗煤泥的粒度分析,推测该方法也适于其他种类浓密膏体的粒度分布测量。     

稀土永磁材料NdFeN三种粒度分析方法的比较

粉体粒度及粒度分布是粉体颗粒最重要的特性。以稀土永磁材料NdFeN为例,采用激光散射法（干法和湿法）和扫描电镜法对其粒度进行了分析,并比较了三种方法的测试结果。测试结果显示,粒度分析时样品的充分分散是准确测量的基础。将显微镜的直观与激光粒度仪的快速、准确和方便结合起来,对于保证粒度分析结果的可靠性非常有用。     

测量范围设定对激光粒度检测结果的影响

激光粒度测试仪在微粉行业得到广泛的应用，正确的使用，结合扫描电镜可以给出粉体颗粒大小的准确量度。引起粒度测量的误差原因很多，本文中讨论激光粒度仪测量范围的设定对粒度测量结果的影响。     

激光粒度仪颗粒联测的结果与评价

为了解不同激光粒度仪的硬件、软件等方面差异对粒度测量结果的影响,用4种颗粒形状不同的粉末在不同公司生产的激光粒度仪上进行测试。结果表明:激光粒度仪测试结果重复性很好;对于球形粉末和形状较规则的粉末,大部分激光粒度仪测得的中位径值之间可以比较;而粒径范围较宽和不规则形状粉末,个别仪器测量的中位径值有差异。     

激光粒度仪测定煤粉粒度及分布的方法研究

采用激光粒度分析仪对具有粘附特性的3种煤粉的粒度及其粒度分布的测试方法进行了研究,以获得最佳测试效果;分别研究样品浓度、吸收率和折射率、表面活性剂、进样器泵转速以及超声时间等因素对煤粉粒度测量结果的影响。结果表明:表面活性剂和进样器泵转速对煤粉的测定结果影响较大,泵转速为1 800~2 600 r/min,加入约3 mL无水乙醇作表面活性剂时测量结果重复性好,数据比较准确。     

马尔文激光粒度分析仪粒度检测方法及其优化研究

介绍了英国马尔文激光粒度分析仪的工作原理 ,研究了该仪器对不同粒度、已知和未知光性参数的粉料进行粒度检测时最佳参数的确定方法 ,对比了干法测量和湿法测量的结果 ,并将分析结果与SEM照片相对比 ,研究了该仪器分析结果的准确性。     

激光粒度分析和筛分法测粒径分布的比较

分别采用筛分法和马尔文激光粒度分析仪两种方法对16种颗粒的粒径分布进行了测量。通过比较,发现两种测量手段得到的粒径分布结果存在较大的差异,马尔文激光粒度方法对颗粒粒径的测量结果偏小,受颗粒形状的影响很大;筛分法对微细颗粒的测量误差较大,但对大粒径颗粒的测量较为准确。通过对不同粒径段灰颗粒的显微照相,发现细颗粒的团聚是筛分法测量小颗粒结果偏小的主要原因。     

激光粒度测量的应用与前景

激光粒度仪是一种应用广泛而又比较有发展前途的粒度测量设备.介绍了激光粒度仪的测量原理,介绍和对比了Fraunhofer衍射和Mie散射理论在激光粒度仪中的应用,探讨了如何评价激光粒度仪以及在线测量的一些技术难题,并展望了激光粒度仪的应用前景和发展方向.     

激光衍射法测定超细氢氧化铝粒度中分散条件的控制

如何控制分散条件是激光衍射法测定超细氢氧化铝粒度的瓶颈。通过对激光衍射法测量原理的描述,并以Mastersizer 2000激光粒度仪为主要分析仪器,通过对外加大功率超声器控制分散时间、外加分散剂、控制样品加入量等分散手段进行研究探讨,找到了测定超细氢氧化铝粒度合理的分散条件。试验证明:在此条件下测量结果的平行性好、准确度高。     

彩色负片的影像颗粒度

本文从卤化银颗粒、主成色剂分散及应用、以及DIR、DLAR成色剂的研究应用探讨改善彩色负片影像颗粒度的方法。     

微细化玉米淀粉粒度效应及其流变学行为研究

采用现代粉体机械可制备微细化玉米淀粉。随着淀粉粒度减小,其支链淀粉和直链淀粉糊的特性黏度降低,分子量下降。布拉班德黏度分析表明,微细化玉米淀粉糊化起始温度下降,热糊稳定性增强;在冷却阶段,随着粒度降低,微细化玉米淀粉的凝沉性较原玉米淀粉增强,冷糊稳定性较原玉米淀粉减弱。微细化玉米淀粉糊为非牛顿假塑性流体,其流动性随粒度降低而增加,并显示出一定的粒度效应。     

流化床喷雾造粒产品粒度分布的影响因素研究

在一下端直径188mm、上端直径396mm、高1000mm的倒锥形流化床喷雾造粒器内,以碳酸钙(CaCO3)粉末作为制药工业上的替代性原料,以明胶作为粘结剂,实验研究了床层温度、流化气速、雾化空气压等因素对造粒产品粒度分布的影响。结果表明,在本实验范围内,造粒产品颗粒的平均粒径随着流化气速、床层温度、雾化空气压的增大而减小,且粒度分布趋向于发散。     

用于热敏CTP版材的版基砂目的研究

本文根据热敏CTP版的特点，研究铝版基的砂目粗糙度对版材成像性能的影响。研究了砂目粗糙度与版材的感光度、显影宽容度和亲水保水性的关系。确定了版基的砂目粗糙度最佳范围在0．4-0．5μm，可以实现1-99％的精细网点还原。     

E5015（J507）焊条药皮中大理石的颗粒度对其熔敷金属化学成分及力学性能的影响

选取大理石作为研究对象,对大理石粉料进行了筛分并进行了焊条制备和测试。研究了药皮原料中大理石的颗粒度对E5015焊条熔敷金属化学成分及力学性能的影响。试验结果表明：随着大理石颗粒度的减小（由40—60目减小至100目以下）,E5015焊条的熔敷金属化学成分Si、Mn含量逐渐下降,其熔敷金属屈服及抗拉强度逐渐降低而冲击功则逐渐升高。     

温度对爆轰法合成纳米氧化铝晶型及晶粒度的影响

用爆轰法合成了纳米γ氧化铝粉体。对粉体分别进行从室温加热到600℃、800℃、900℃、1000℃、1100℃和1300℃的煅烧处理,对煅烧样品进行了X射线衍射分析,研究了不同煅烧温度下,纳米氧化铝的晶粒度。结果表明,随煅烧温度的升高,纳米氧化铝经历了从γ型转变成δ型,再转变成θ型,最后完全转变成α型纳米氧化铝的过程。随着加热温度的升高,纳米氧化铝出现了晶粒细化现象,且晶粒细化有两个过程,细化程度最大的温度区间为800~1000℃。     

面向对象多粒度概念格的构造

如何降低概念格构造过程中的复杂度是形式概念分析中一个重要的研究课题．粒计算可以从多个角度对问题进行分析、求解,已经成为人工智能领域中研究问题的有效工具．针对多粒度概念格的快速构造问题,基于粒计算理论,本文研究了属性粒度变化前后概念外延与内涵之间的关系,定义了不同类型的概念,提出了基于不同属性粒度组合的面向对象概念格转换算法---Zoom,具体包括对属性粒度进行细化的Zoom-in算法和对属性粒度进行粗化的Zoom-out算法．Zoom算法在原概念格的基础上直接实现新概念格的构造,避免了遵循传统的概念格构造方法时从新形式背景中生成新面向对象概念格的繁琐步骤,从而提高了概念格的构造效率,可以快速确定概念格的属性最优粒度组合,进而有助于在数据中进行数据挖掘和知识发现．     

DC Electrical Resistivity Study of Granularity in YBa2CU3O7/Ag Composites

Temperature-dependent electrical resistivity in a set of YBa₂Cu₃O_7–x /Ag composites, all prepared under an identical sintering schedule, is analyzed to extract granularity information. The weak-link resistivity _wl across the grain boundaries and the percolation factor arising due to current frustration caused by misalignment of anisotropic grains and sample defects such as voids and cracks are estimated from the residual resistivity ₀ and the temperature coefficient of resistivity d/dT. Variation of these parameters with Ag vol.% quantifying the extent of granularity indicates that granularity in the composites decreases and their electrical characteristics tend to be identical to that of Ag-free YBa₂Cu₃O_7–x single crystals and epitaxial thin films as Ag vol.% approaches a value where onset of current percolation occurs through Ag channels. The increased and decreased _wl observed at higher Ag vol.% explains the larger grains in the composites with narrow size distribution.     

The Role of Photon Noise in Granularity

The granularity of the silver deposit which results from a light exposure of a photographic emulsion layer, when considered in terms of the number of incident quanta, is very high in comparison with the cases of X-ray exposures and I-quantum systems generally. It has been suggested that the high granularity can be attributed to an amplification of the incoming photon noise by the photographic layer and that the response of the layer as far as contrast and granularity are concerned is equivalent to that of an ideal recorder at a much lower exposure. This suggestion is open to the criticism that for light exposures granularity appears to be independent of the exposure required to obtain it and is an intrinsic property of the silver deposit. It is argued that if the processes of exposure and development are to reduce grains to silver at random, which were already arrayed at random in the emulsion layer, then the mechanics of the selection processes cannot contribute to the granularity.

Detailed analyses of both chequer-board and more realistic models of the photographic layer for exposures in which the granularity sample patches each receive the same number of photons indicate that granularity involves the noise of “partitioning” the incident photons amongst the grains in each sample patch. In abandoning the assumptions of randomness of deployment and selection of grains on exposure, it is convenient to introduce two “noise reduction” principles which govern the way in which grain crowding and photon noise are associated. The use of these principles leads to the relation:

G² = P² + QG²,

in which G is the Selwyn granularity, P is the analogous quantity for a fixed number of photons incident on each sample patch and Q is the detective quantum efficiency. This equation expresses the physical indistinguishability of low-frequency photon noise and large-area signals—the difference is merely one of labelling. Furthermore, it can be deduced that since Q is small in practice for light exposures, the degree of non-randomness associated with grain crowding is almost negligible. In the absence of light scatter in the layer, the partition noise arises partly from incoming high-frequency photon noise; the granularity may therefore be deemed to originate in part in photon noise and to be an amplified form of its low-frequency components. A new definition of Q is suggested which leads to a simple interpretation of a frequency-dependent efficiency.