悬浮液进样FAAS法测定土壤样品中微量锰

采用悬浮液进样火焰原子吸收光谱法(FAAS法)测定土壤样品中微量锰;并对样品的粒度、悬浮液的浓度、介质酸度、校正方法及抗干扰等进行了探讨.结果表明,本法简便、快速、准确可靠.     

悬浮液进样FAAS法测定土壤样品中微量锰

采用悬浮液进样火焰原子吸收光谱法（ＦＡＡＳ法）测定土壤样品中微量锰；并对样品的粒度、悬浮液的浓度、介质酸度、校正方法及抗干扰等进行了探讨。结果表明，本法简便、快速、准确可靠。     

高能球磨法制备Fe_3O_4超细颗粒过程中转速对其性能的影响

采用高能球磨法制备水基Fe_3O_4磁性颗粒,研究了转速对其研磨效果、粘度、沉降稳定性、样品形貌及流变性能的影响。结果表明:球磨机转速对Fe_3O_4磁性颗粒悬浮液的粘度和沉降稳定性的影响很大。在相同的研磨时间内,随着转速的提高悬浮液中超细颗粒的含量增多,转速为200 r/min,球磨机对物料有很好的研磨效果;悬浮液的零场粘度先增大后减小;悬浮液的沉降率先减小后增大,沉降量是先变少后变多的过程,当球磨机转速定为200 r/min时,所得样品的稳定性最好;磁场强度低于65 mT时,在相同磁场强度下,低转速制取样品的剪切应力较大。磁场强度高于65 mT时,在相同磁场强度下,高转速制取样品的剪切应力较大。     

悬浮液进样石墨炉原子吸收光谱法测定饲料样品中痕量铜

采用悬浮液进样技术并结合灵敏度较高的石墨炉原子吸收光谱法测定饲料样品中的痕量铜 ,对悬浮液介质、基体改进剂进行了选择 ,对灰化和原子化过程进行了探讨。本法的精密度 (RSD)为 4 12 % ,加标收回率为 97 0 %     

ZetaPlus激光粒度仪测量聚丁二烯胶乳粒径影响因素浅析

通过建立不同浓度聚丁二烯胶乳(PBL)悬浮液与其浊度的对应关系,考察了PBL悬浮液浊度对其粒径测量的影响,同时探讨了样品测量温度及样品稳定时间等测量影响因素,为研发及生产中准确获得PBL粒径测试数据提供一定指导作用。     

悬浮液进样石墨炉原子吸收光谱法测定饲料样品中痕量铜

采用悬浮液进样技术并结合灵敏度较高的石墨炉原子吸收光谱法测定饲料样品中的痕量铜，对悬浮液介质、基体改进剂进行了选择，对灰化和原子化过程进行了探讨，本法的精密度（RSD）为4.12%，加标收回率为97.0%。     

原子吸收光谱的样品前处理方法进展

概括了常用的原子吸收光谱的前处理技术,重点介绍了最新现代原子吸收光谱前处理技术和这些前处理技术在环境样品、食品样品、人体组织样品和土壤样品分析中的应用。这些新的技术包括,超声波辅助萃取,微波辅助萃取,微波消解,浊点萃取技术,纳米材料运用于萃取技术,非完全消化技术,悬浮液进样法,在线富集等。     

用空气氧化两价铁悬浮液生成α-FeOOH的过程

本文对在40℃用空气氧化Fe(OH)_2悬浮液生成α-FeOOH的过程中的反应条件进行了研究。通过考察α-FeOOH样品的比表面积,X-射线衍射峰及电子显微镜照片,估算出颗粒尺寸;氧化过程中粒子的生长速度随最初悬浮液中Fe(OH)_2和过量NaOH浓度的增大而增大。而在有NH_4~+离子存在的中性悬浮液中,生长速度则随Fe(OH)_2浓度的增大而增大。粒子形状和尺寸分布狭窄的α-FeOOH,通过热处理制成针状Fe_3O_4,或γ-Fe_2O_3样品,并在室温下测试其磁性指标。     

高浓度纳米颗粒悬浮液粒径的超声在线测量方法研究

为研究高浓度纳米颗粒悬浮液的粒径分布表征,引入超声谱高浓度颗粒粒径测量理论(核壳模型),同时搭建了一套超声法高浓度悬浮液粒径测量实验装置,并进行理论模型的实验验证,测得体积浓度为10%至30%的纳米铟锡金属氧化物(Indium Tin Oxides,ITO)水性悬浮液的超声衰减,通过数据反演技术最终获取样品的颗粒粒径分布。结果表明:高浓度纳米颗粒悬浮液中声衰减系数随浓度增加但偏离线性递增趋势,与核壳模型数值模拟更接近。同时,粒径反演的结果与高速离心沉降法也较为吻合。     

无火焰原子吸收测定环境样品中的痕量铅

以琼脂为悬浮体进样,以磷酸二氢铵为基体改进剂,研究了悬浮液的稳定性和基体改进效应对于石墨炉原子吸收法测定环境中痕量铅的影响。结果表明,悬浮液浓度为0.15%,改进剂浓度为1.0%,灰化和原子化温度分别为800℃和2 200℃时能精确测定环境样品中的铅含量。在此条件下,用标准加入法测定土壤和藕粉中的铅含量分别为25.47μg/g和0.6μg/g。     

纳米SiO_x补强天然乳胶膜抗剪切机理的研究

使用合适表面处理剂,通过剪切、搅拌混合和超声波处理,制备了高浓度n—SiOx分散悬浮液;在合适的剪切强度下,将分散悬乳液按n-SiOx质量分数为2.0%均匀分散在天然乳胶中,制备了n-SiOx补强型天然乳胶膜试样。乳胶膜直角撕裂强度测试结果和扫描电子显微镜图像分析表明,n-SiOx粒子较好地分散在天然乳胶中,能与乳胶分子链形成较为牢固的整体结构,其剪切强度较白炭黑试样提高了52.32%;n-SiOx悬浮液浓度是实验的主要影响因素,超声波分散时间、25G工作头转速和均质分散时间次之。     

电石渣硅铁用作重介质悬浮液加重质的研究

电石渣的排放及贮存量日益递增,电石渣硅铁的资源化利用也成为亟待解决的难题。为实现电石渣硅铁的高值化应用,以干法电石渣中分离出的磁性硅铁为加重质配制重介质悬浮液,并探究了悬浮液密度、黏土含量和硅铁粒度等因素对其粘度及沉降特性的影响。结果表明,增大悬浮液密度或黏土用量以及减小硅铁粒度均会使悬浮液的粘度提高,从而使加重质颗粒的沉降速度下降,稳定性得到提升。此外,为了进一步验证该悬浮液体系用于实际分选的可行性,将不同密度的悬浮液用于选煤浮沉试验分选混合煤样,在密度为1.30 g/cm³和1.40 g/cm³的重介质悬浮液中,浮煤产率高且灰分含量较初始煤样大幅降低,说明该悬浮液体系具有良好的分选性能。     

ZnO/活性碳纤维的制备及其抗菌性能

以活性碳纤维为载体,乙二醇为分散液,将碳纤维浸渍于含ZnO粉体的乙二醇溶液中制得ZnO/活性碳纤维样品,测试了样品的抑菌性,并比较了分散液中添加表面活性剂SDBS对ZnO分散的影响以及负载有ZnO前后碳纤维吸附性能变化。结果表明,表面吸附有5.50%ZnO的活性碳纤维对金黄色葡萄球菌抑制作用明显,且对碳纤维本身吸附性能影响不大,添加表面活性剂SDBS后能使ZnO的分布更加均匀,适合于用作医用敷料。     

Suspension stability and sintering influence on yttria-stabilized zirconia fabricated by colloidal processing

The stability of nano-zirconia 3YSZ powder in suspension was extensively studied by the colloidal method, and the optimum sintering temperature of the green sample fabricated through slip casting was determined. Zirconia suspensions with 10 vol% powder loading were prepared with distilled water, and HNO₃ was used to adjust the pH of the suspension to pH 1–6. All of the suspensions were subjected to sedimentation test, and the results showed that the suspensions adjusted to pH 2 had the lowest sediment volume. This finding indicates that a suspension with pH 2 produces higher packing density. Viscosity test was carried out for the suspensions added with dispersant ranging from 0.3 wt% to 0.7 wt% polyethyleneimine (PEI) with and without pH adjustment. The suspension containing 0.5 wt% PEI with pH 2 adjustment produced the lowest viscosity because of interparticle bond breakage in the aggregates, thus forming colloidally stable suspensions. The zirconia suspension containing 0.5 wt% PEI and whose pH was adjusted to pH 2 was chosen to be slip casted into cylindrical shape. Green samples were sintered at various sintering temperatures that ranged from 1100 °C to 1500 °C through a two-step sintering method. The sample sintered at 1500 °C was found to be porosite-free, and its highest relative density was 99.6% of the theoretical density. Morphological studies detected pores in the microstructure of the samples sintered at low sintering temperatures (1100 and 1200 °C). By contrast, the samples sintered at 1400 and 1500 °C were fully densified. However, the grain size of the sample sintered at 1500 °C was 230 nm, which indicated excessive grain growth. The Vickers hardness of the sample sintered at 1400 °C was found to be highest (12.9 GPa) and comparable to results found in the literature.     

23%乙螨唑·三唑锡悬浮剂对柑橘红蜘蛛的田间药效研究

乙螨唑为噁唑类新型专用杀螨剂,三唑锡为触杀作用较强的广谱性杀螨剂,由二者制成的复配悬浮剂可起到增效作用。开展了对23%乙螨唑·三唑锡悬浮剂防治柑橘红蜘蛛的田间药效试验。结果表明,有效成分浓度为200、100、50 mg/kg的23%乙螨唑·三唑锡悬浮剂,防治柑橘红蜘蛛速效性好,持效期长;药后1、3、10、15、20、30 d的防效均达到95%以上,与对照药剂20%三唑锡悬浮剂100 mg/kg和110 g/L乙螨唑悬浮剂比较,各处理与三唑锡对照防效相当,极显著优于乙螨唑对照。     

Further observations on the rheological behaviour of dense suspensions

The literature and recent WSL results on suspensions of spherical particles are surveyed and summarised. It is concluded that the steady shear properties of a dense suspension is not characterised by an unique viscosity or flow curve, but rather it is described by a wide viscosity distribution or a shear stress - shear rate flow band whose mean and standard deviation are functions of solids concentration, particle size distribution and viscometric geometry and dimensions. The standard deviation (or data spread) increases with solids concentration and with decreasing viscometer gap to particle diameter ratio. This property is due to poor sample reproducibility in respect of solids concentration and particle size distribution and the inherent two-phase nature of suspension which gives rise to particle migration and consequently non-uniform packing density or structure in a sample. Because a dense suspension is increasingly sensitive to these factors as concentration is increased, the standard deviation can be very large. Because the details of packing structure vary with flow, the viscosity distribution or flow band depends on viscometric flow geometry and measuring element dimensions. The implications of this conclusion on the study and characterisation of dense suspension property and the prediction of its behaviour in industrial handling and process equipment are discussed.     

功能化碳微球构建自组装膜

采用浓HNO3和H2O2对原始CMSs进行表面修饰,使其团聚现象得到改善;以氧化后CMSs作为结构基团,采用垂直沉积法实现CMSs的自组装,得到CMSs薄膜.考察了溶剂、悬浮液pH值、悬浮液浓度和反应温度对自组装的影响.采用场发射扫描电子显微镜和原子力显微镜对产物进行表征分析,结果表明,以NaOH溶液为溶剂配制悬浮液、...     

氯乙酸副产气中总硫含量间接分光光度法测定

研究了铬酸钡分光光度法应用于氯乙酸副产混合气中总硫含量测定的实例。探讨了气体采集、样品溶液处理和铬酸钡悬浮液配制等关键问题。硫元素经碱液吸收和双氧水氧化完全转化为硫酸根,硫酸根再与铬酸钡悬浊液反应,定量置换出铬酸根,溶液的吸光度即与硫酸根的浓度成正比。该方法的测定波长为372 nm,硫酸根质量浓度在0～10 mg/L线性关系好。该方法操作简单,精密度和准确度均符合测定要求,适用于工厂气体的实时监测。     

Numerical evaluation of the size distribution of particles obtained by suspension polymerization using data of the Coulter Counter TA II apparatus

The particle size distribution determined by means of the Coulter Counter TA II (CC TA II) apparatus was compared with two artificial distributions prepared from fractions of polymeric spherical particles. The data were numerically treated using a new distribution function, and the fit was satisfactory. The applicability of CC TA II along with the numerical and graphic evaluation is documented for a real sample of the product of suspension radical polymerization.     

木薯淀粉-丙烯酰胺共聚物对污水的絮凝效果

实验室自制木薯淀粉-丙烯酰胺接枝共聚物（CSAAGC）作为絮凝剂处理不同来源污水。探讨了CSAAGC加入量、污水pH及絮凝时间对絮凝效果的影响。结果显示,CSAAGC的pH使用范围为3.0~10.0;对模拟污水的浊度去除率达97%;对滇池水的浊度去除率达84%;对泥浆悬浊液的30 m in浊度去除率达59%;对生活污水的浊度去除率为82%。同时测定了处理前后滇池水及生活污水的CODC r值,对滇池水CODC r去除率47.4%;对生活污水的CODC r去除率为56.4%。