共查询到20条相似文献,搜索用时 750 毫秒
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《中国洗涤用品工业》2017,(8)
阐述了洗涤用酶微丸的3种常用造粒方法。并进一步阐述了造粒设备的基本原理和优缺点及其工业化生产的可能性。喷雾造粒法一般应用于生产粉剂和微小颗粒。挤压造粒法的处理量大、成本低,适合大规模生产。流化床造粒喷雾法制出的微丸颗粒圆整、储存性好,极大地增强了颗粒的湿热能力,并且在设备中一步完成混合、喷雾、制粒和干燥等过程,但对设备要求高,设备较为昂贵。造粒是一项复杂的物理过程,要综合考虑造粒设备、成本、生产效率和颗粒质量等因素,将上述3种造粒方法结合也是如今的研究热点。 相似文献
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复混肥生产装置改产脲甲醛缓释复合肥料的技术 总被引:1,自引:0,他引:1
利用转鼓蒸汽造粒或圆盘造粒复混肥生产装置改造并开发生产脲甲醛缓释复合肥。介绍脲甲醛的生产原理、反应条件控制和脲甲醛缓释复合肥的生产过程。尿素熔融喷浆工艺的转鼓蒸汽造粒复混肥装置改产脲甲醛缓释复合肥具有投资少、工期短、生产成本低于包膜控释肥等优点。该肥料中包含了速效、中效、长效的氮素养分.其氮素利用率可达50%,减少30... 相似文献
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农药缓释、控释制剂的研究进展 总被引:1,自引:0,他引:1
综述了具有缓释控释功能的农药制剂的最近进展,并着重介绍了微胶囊和共聚物的特点、制备方法和释放机理。指出具有缓释控释功能的剂型近年来正在成为农药制剂的新热点、新趋势。 相似文献
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1-脱氧野尻霉素控释微丸采用挤出滚圆和流化床方法进行制备。首先使用羟丙基甲基纤维素和微晶纤维素等辅料制备分散体、丸芯,再使用羟丙基甲基纳米纤维素邻苯二甲酸酯作为主要包衣材料进行包衣,并装入胶囊。采用SEM观察微丸的微观形态,以及测定其产率、脆碎度、密度、水分含量和粒径分布等物理性质,研究结果显示微丸性质符合中国药典标准规定。在体外释药试验中,溶出介质和放置方式对药物释放无显著影响,释放过程符合Baker-Lonsdale模型。对比研究1-脱氧野尻霉素原料药、分散体微丸和控释微丸在比格犬体内的控释特性,结果表明:与1-脱氧野尻霉素原料药相比,分散体微丸和控释微丸分别使1-脱氧野尻霉素的生物利用度提高了183.37%和243.87%。此外,1-脱氧野尻霉素控释微丸的体内-体外研究的相关性分析可知体外溶出和体内吸收之间呈现良好的线性关系。 相似文献
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制备双氯芬酸钠肠溶缓释微丸并考察体外释放特性.采用离心制粒包衣技术,用蔗糖和淀粉采用离心起母的方式制备空白丸芯,用缓释材料在空白丸芯表面制备含处方量主药2/3的骨架缓释内层,用肠溶材料制备含处方量1/3的肠溶外层,再于微丸表面包覆一层缓释衣,可以制得稳定性良好的双氯芬酸钠肠溶缓释微丸.成品微丸收率95%以上,粒径在25... 相似文献
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海藻酸钠微球是传统缓控释制剂,提高凝胶强度和增大毛细孔隙率是改善其缓控释性能的有效途径。本文以原子吸收分光光度法辅以微观形貌表征(SEM)和溶胀实验等分析方法,探讨了凹土/海藻酸钠复合微球用于以生命体中微量元素(Cu2+)控释的可行性,并进行了缓释机理分析。实验结果表明,凹土具有显著改善微球的凝胶强度和缓释性能的作用;与海藻酸钠微球相比,复合微球的吸附率由91.82%提高到94.60%,在2 h之内的释放率由66.35%降低到22.78%,表明凹土/海藻酸钠复合微球可作为理想的长效缓释药物的载体。 相似文献
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分散剂在醇-水溶液加热法制备球形 ZrO2粉体过程中的作用 总被引:18,自引:4,他引:14
本工作对分散剂在醇-水溶液加热法制备球形ZrO2粉体过程中的作用进行了研究。研究结果表明:在异丙醇-水溶液加热法制备球形ZrO2粉体时,聚合物分散剂起着明显的作用。当无分散剂加入时,所得ZrO2颗粒无规则且团聚严重;而当溶液中加入PEI(polyethyleneimine)时,可获得球形ZrO2颗粒,与加入PEI相比,加入NH4PAA或PEG所得ZrO2颗粒形状不够完整且团聚较多,这一区别可由聚合物分散剂在ZrO2颗粒上的吸附情况的不同得到初步解释。 相似文献
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《Journal of Adhesion Science and Technology》2013,27(18-19):2199-2215
Abstract Droplet dynamics analysis concerns the measurements of droplet volume, cap and base areas and contact angles, as they change in time to study evaporation, wettability, adhesion and other surface phenomena and properties. In a typical procedure, the two-dimensional measurements are based on a series of images recorded at successive stages of the experiment from a single view. Only a few basic dimensions of sessile droplets are commonly measured from such images, while many other quantities of interest are derived utilizing geometrical relationships. The reliability of these calculations is limited by the necessary assumption that the droplet shape can be approximated as a spherical cap. In reality, the sessile droplet shapes are influenced by gravity, liquid surface tension, local surface anisotropy and microstructure, which often produce non-spherical cap shapes. This paper describes an experimental methodology for determination of key parameters, such as volume and contact angle for dynamic sessile droplets that can be approximated either by spherical or ellipsoidal cap geometries. In this method, images collected simultaneously from three cameras positioned orthogonally to each other are used to record the dynamic behavior of non-spherical droplets. Droplet shape is approximated as an ellipsoid of arbitrary orientation with respect to the cameras, which allows determination of volume and contact angle along the base perimeter. A major advantage of this method is that the dynamic parameters of droplets on anisotropic surfaces can be determined even when the orientation of the axes changes throughout the droplet lifetime. The method is illustrated with experimental results for a spherical and an ellipsoidal droplet. 相似文献
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球形碳酸锰微晶制备过程中的形貌控制 总被引:1,自引:0,他引:1
以MnSO4和NH4HCO3为原料,采用低温化学沉淀法制备出了粒度主要为5~6 mm的单分散MnCO3球形颗粒. 通过扫描电镜研究了各种反应条件如温度、pH值、MnSO4和NH4HCO3浓度等对MnCO3颗粒形貌和粒度的影响,并初步探讨了其可能的生长机理. 结果表明,溶液的pH值是影响MnCO3颗粒形貌的关键因素,当pH值在8.0~7.0范围内减小时,MnCO3颗粒形貌由立方形向球形转变. 随着反应温度的降低,MnCO3颗粒的分散性趋好,其形貌也逐渐趋于形成均一的球形颗粒,但粒径增大. 在实验范围内,NH4HCO3浓度控制在0.1~0.3 mol/L有利于球形MnCO3颗粒的生成,MnSO4浓度在0.05~0.4 mol/L变化对产物的形貌影响不大. XRD分析证实了沉淀产物为MnCO3晶体,属三方晶系,方解石晶型. 相似文献
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Yongzhi Zhao Hongyi Xiao Paul B. Umbanhowar Richard M. Lueptow 《American Institute of Chemical Engineers》2018,64(5):1550-1563
Many products in the chemical and agricultural industries are pelletized in the form of rod‐like particles that often have different aspect ratios. However, the flow, mixing, and segregation of non‐spherical particles such as rod‐like particles are poorly understood. Here, we use the discrete element method (DEM) utilizing super‐ellipsoid particles to simulate the flow and segregation of rod‐like particles differing in length but with the same diameter in a quasi‐2D one‐sided bounded heap. The DEM simulations accurately reproduce the segregation of size bidisperse rod‐like particles in a bounded heap based on comparison with experiments. Rod‐like particles orient themselves along the direction of flow, although bounding walls influence the orientation of the smaller aspect ratio particles. The flow kinematics and segregation of bidisperse rods having identical diameters but different lengths are similar to spherical particles. The segregation velocity of one rod species relative to the mean velocity depends linearly on the concentration of the other species, the shear rate, and a parameter based on the relative lengths of the rods. A continuum model developed for spherical particles that includes advection, diffusion, and segregation effects accurately predicts the segregation of rods in the flowing layer for a range of physical control parameters and particle species concentrations. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1550–1563, 2018 相似文献
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以聚乙烯吡咯烷酮为控制剂,氯化镁、氢氧化钠和氨水为原料,经静态反应制备出球形氢氧化镁前驱体,再经煅烧得到球形氧化镁。研究了控制剂种类、控制剂用量、反应物浓度、反应时间等因素对球形氧化镁形貌的影响,并用XRD、SEM等分析手段对产物做了表征。结果表明:在控制剂为聚乙烯吡咯烷酮、添加量为1.0%(质量分数)、氯化镁浓度为1.0 mol/L、氢氧化钠浓度为0.25 mol/L、反应时间为24 h的条件下,获得球形氢氧化镁前驱物;前驱物氢氧化镁在600 ℃下煅烧2 h,制得的球形氧化镁颗粒大小均匀、分散性好、球形度高,平均粒径为4.53 μm。 相似文献