免疫检测用纳米胶体金的制备及粒径控制

利用柠檬酸钠作为还原剂,采用液相还原法制备了适用于免疫检测的胶体金纳米颗粒。用透射电子显微镜和紫外/可见光分光光度计分别对胶体金颗粒的形貌和光学吸收特性进行了检测。结果表明,柠檬酸钠的加入量是影响胶体金颗粒粒径和形貌的主要因素,制备100ml0.01%胶体金溶液,1%柠檬酸钠溶液加入量小于5ml时,胶体金颗粒的平均直径随柠檬酸钠加入量的增加而减小,当大于5ml时,胶体金颗粒的平均直径随柠檬酸钠量的增加而增大。在研究范围内,胶体金颗粒的平均粒径与最大吸收峰波长之间存在直线回归关系。制备的胶体金呈单分散的球形分布,具有较高的生物学活性,适用于胶体金免疫检测。     

硫掺杂偏钛酸粉体的制备

以硫酸钛为原料,采用水解法制备了硫掺杂偏钛酸粉体,采用场发射扫描电镜(FESEM)、激光粒度分析等技术对偏钛酸粉体的形貌及粒度进行了分析.系统研究了硫酸钛溶液浓度、水解温度、pH值对水解率、偏钛酸粉体粒径的影响,研究结果表明:硫酸钛溶液浓度、pH值及水解温度对偏钛酸颗粒粒径及原料水解率具有显著影响.最佳工艺条件为:硫酸钛溶液的质量浓度为65 g/L、水解温度60℃、pH值为7.     

液相还原法制备车电容用微纳米铜粉的特性表征研究

采用液相还原法制备车电容用微纳米铜粉,通过X射线衍射仪和扫描电子显微镜研究pH值、混合方式对产物成分、形貌和粒径的影响。结果表明:当溶液pH值为6或8时,制得的产物为面心立方结构的Cu粉;随着pH值增大到10,产物中除了存在单质金属Cu,还有Cu_2O相。铜产物颗粒形状为不规则的光滑多面体结构,颗粒粒径随pH值增大不断降低。同样实验条件下(溶液pH值为3),以倾倒方式进行混合得到的铜粉产物粒径尺寸分布窄,颗粒尺寸约为1μm,具有良好的分散性。     

热分解法制备喷涂用Co-Cr-V复合粉末

采用热分解法制备喷涂用Co-Cr-V复合粉末,并测定其物相及元素组成、粉末平均粒径以及电位,分析其微观组织形貌与溶液pH值之间的关系。结果表明:采用热分解法,V与Cr原子都已进入到Co金属基体的晶格内,得到Co-Cr-V置换固溶体结构。不同pH值条件下制备得到的复合粉末颗粒均具有球形微观结构并存在团聚现象。随着溶液pH值的增加,复合粉末颗粒互相接触并团聚为大尺寸块状结构。当溶液pH值较小时,Zeta电位与等电位点存在较大偏差,颗粒分散性良好;随溶液pH值增大,粉末颗粒发生明显团聚,颗粒平均粒径随之增大。     

钍(Ⅳ)离子在泥炭上的吸附研究

采用静态批次吸附法研究了泥炭对Th4+的吸附行为。探讨了泥炭粒径、固液质量体积比、振荡时间、溶液pH值、离子强度等因素对吸附的影响,并确定了室温下不同离子强度时的吸附等温线。试验结果表明:溶液pH值对泥炭吸附Th4+影响较大,离子强度的影响较小;吸附过程符合Langlmuir方程;泥炭对Th4+的吸附主要通过表面络合进行。     

沉淀法制备掺锆氧化锌纳米粉末的形貌与光学性能

采用直接沉淀法制备未掺杂和掺杂Zr元素的ZnO纳米粉末,通过X射线衍射(XRD)分析、扫描电镜(SEM)、能谱分析(EDS)以及紫外可见光谱(UV-Vis)分析、光学性能测试等,研究Zr掺杂量(0~5%,摩尔分数)与溶液pH值(6.5~13.0)对粉末粒度、形貌与结构及光学性能的影响。结果表明:Zr掺杂使ZnO粉末粒径减小。Zr掺杂量为1%的粉末粒径最小,晶粒尺寸为28 nm,Zr完全进入ZnO晶格中;当Zr掺杂量增加到3%和5%时,粉末粒径增大,并出现ZrO2相。反应溶液的pH值为6.5时,Zr-ZnO纳米粉末形貌为类球形。随pH值增大,Zr-ZnO粉末形貌逐渐向短棒状转变,粉末粒径先减小然后增大。随Zr掺杂量从0增加到5%,ZnO的光吸收峰先出现"蓝移"后出现"红移",表明Zr掺杂可提高ZnO粉末的禁带宽度,随Zr含量增加,粉末的禁带宽度先增大后减小,1%Zr-ZnO的禁带宽度最大。     

亚硝基R盐分光光度法快速测定硫酸锌溶液中的钴

研究了亚硝基R盐与钴在pH值5~6的溶液中发生显色反应,反应产物在520 nm处有最大吸收峰。该测定方法快速、简便,能满足湿法炼锌生产的要求。     

银氨体系双氧水还原法制备超细银粉

硝酸银溶液中加入浓氨水配制成一定pH的银氨溶液,加入双氧水作还原剂制备超细银粉,对加料方式、银氨溶液pH值、AgNO_3溶液浓度、双氧水浓度等参数以及分散剂对银粉的影响进行研究。结果表明,采用正向快速加料法可制备出分散性好的银粉;调节银氨溶液pH值可改变银颗粒的Zeta电位,进而改变银粉的分散性;银粉粒径随双氧水浓度提高先增大后减小,随AgNO_3溶液浓度提高而增大;分散剂对银粉形貌有较大影响。在硝酸银溶液浓度为0.1~0.3mol/L,银氨溶液pH值为10.0~11.0,双氧水浓度(质量分数)为3%的条件下,不使用任何分散剂可制备出分散性较好、平均粒径1.9~2.3μm的类球形银粉。     

精炼废渣中CaS水化浸出的热力学及实验研究

若实现精炼废渣的循环利用,须去除其中的有害元素硫,为此,本文首先通过热力学计算绘制了不同条件下CaS-H2O体系的E-pH图,并对CaS水化后各物质的稳定区域进行了分析,之后对CaS进行了水化浸出实验,研究了溶液pH值及温度对硫浸出率的影响,结果表明:随着溶液pH值的增大,Ca元素的存在形式呈Ca~(2+)→CaSO4→Ca(OH)2的变化规律,S元素的存在形式呈HSO_4~-、S→CaSO_4→SO_4~(2-)的变化规律,硫的浸出率呈先降低后升高的趋势,常温下硫的最高浸出率为61%;随着温度的升高,CaSO_4的稳定区域逐渐缩小,Ca~(2+)+HSO_4~-和Ca(OH)_2+SO_4~(2-)的稳定区域不断扩大,硫的浸出率不断升高,373 K时硫的浸出率为71%.     

精炼废渣中CaS水化浸出的热力学及实验研究北大核心

若实现精炼废渣的循环利用,须去除其中的有害元素硫,为此,本文首先通过热力学计算绘制了不同条件下CaS-H2O体系的E-pH图,并对CaS水化后各物质的稳定区域进行了分析,之后对CaS进行了水化浸出实验,研究了溶液pH值及温度对硫浸出率的影响,结果表明:随着溶液pH值的增大,Ca元素的存在形式呈Ca^(2+)→CaSO4→Ca(OH)2的变化规律,S元素的存在形式呈HSO_4^-、S→CaSO_4→SO_4^(2-)的变化规律,硫的浸出率呈先降低后升高的趋势,常温下硫的最高浸出率为61%;随着温度的升高,CaSO_4的稳定区域逐渐缩小,Ca^(2+)+HSO_4^-和Ca(OH)_2+SO_4^(2-)的稳定区域不断扩大,硫的浸出率不断升高,373 K时硫的浸出率为71%.     

影响二氧化硅溶胶粒径及粒度分布因素的研究

以氢氧化钾为催化剂,用硅粉溶解法制备硅溶胶,通过扫描电镜(SEM)、激光粒度分析(SL)、pH值和粘度测试对所得硅溶胶进行表征.研究反应温度、硅粉加入量、氢氧化钾加入量和反应时间对胶粒粒径、粒度分布以及形貌的影响,并对粒径增长进行理论分析.结果表明:随着反应温度的升高,平均粒径先增大后减小,粒径分散度先减小后增大:随着...     

粒径可控纳米金的制备及表征

以氯金酸(HAuC l4)和硼氢化钠(NaBH4)为原料,柠檬酸钠(Na3C6H5O7)作保护剂,在室温条件下,一步还原制备出了不同粒径的单分散纳米金颗粒。应用X射线衍射仪、透射电子显微镜、激光粒度分布仪和紫外-可见分光光度计对产品进行表征,结果表明,制备的纳米金颗粒呈球形,为面心立方结构;柠檬酸钠保护剂的存在,不但提高了金颗粒的单分散性和稳定性,还在一定程度上抑制了金颗粒的生长,使得其粒径可控,且分布很窄。紫外-可见吸收光谱反映出,随着粒径的增大,胶体金在可见光区的最大吸收峰逐渐向长波方向移动。     

Identifying critical parameters in the settling of African kimberlites

Kimberlite is the host rock of diamonds and varies widely in geological and mineralogical features as well as color, processing capability, and dewatering characteristics. This study investigated the dewatering behavior of problematic Angolan kimberlites. The presence of clay minerals in kimberlite causes difficulties in dewatering due to high flocculant demand, poor supernatant clarity, and low settling rates. Identifying critical parameters governing the settling behavior will assist in managing the settling behavior of different kimberlite slurries. The influence of particle size, pH of the kimberlite slurry, cation exchange capacity, exchangeable sodium percentage, and smectite content of the kimberlite on the settling rate were investigated for 18 different African kimberlite samples. The settling rate and slurry bed compaction during natural settling were also measured for the kimberlite slurries. Seventeen different Angolan clay-rich kimberlites and one South African clay-rich kimberlite were tested, and, except for two kimberlites, colloidal stability was experienced during natural settling. The pH values of the kimberlite slurries ranged between 9 and 11, which is similar to the pH band where colloidal stability was found during earlier research. The results indicate that colloidal stable slurries were experienced with kimberlites that had exchangeable sodium percentages as low as 0.7%. The cation exchange capacity of the various kimberlites differentiated more distinctly between colloidal stability and instability. A new model is proposed whereby clay-rich kimberlites with a cation exchange capacity of more than 10cmol/kg will experience colloidal stability if the pH of the solvent solution is within the prescribed pH range of 9–11.     

Sulphated glycosaminoglycans in guinea pig eosinophils studied by means of cationic colloidal gold

Using bone marrow embedded in hydrophilic resin Lowicryl K4M and cationic colloidal gold pH 1.0 labelling, we studied sites of sulphation and sulphated glycosaminoglycans ultrastructurally in various maturational stages of both eosinophil granulocytes and eosinophil granules of guinea pig. Eosinophil granules reacted positively to cationic gold, the pattern of labelling varying according to the degree of cell maturation. The formation of eosinophil granules takes place throughout the myelocyte stage. Early eosinophil myelocytes contain a large Golgi apparatus with active granulogenesis, while late ones contain a small and less active Golgi apparatus. All the immature granules were labelled positively. However, mature granules with a central crystal bar lost their affinity towards colloidal gold. Interestingly, strong colloidal gold labelling was also observed in the trans to transmost Golgi apparatus, especially in immature eosinophil granulocytes. This indicates that sulphation of glycosaminoglycans occurs in the trans to transmost Golgi apparatus of eosinophil granulocytes. Prior absorption with poly-L-lysine prevented colloidal gold labelling of tissue sections. Methylation of sections at 37 degrees C did not alter the gold labelling, whereas the labelling disappeared after methylation at 60 degrees C. Prior treatment with chondroitinase ABC or heparinase I abolished the majority of colloidal gold labelling in immature eosinophil granules. Taking these results together, we conclude that immature eosinophil granules contain sulphated glycosaminoglycans including chondroitin sulphate or heparan sulphate or both.     

A characterisation of dark-field imaging of colloidal gold labels in a scanning transmission X-ray microscope

While X-ray microscopes provide images of biological specimens for which the contrast is mainly due to the difference in the absorption of carbon and oxygen when X-rays transmitted through the specimen are detected, signals other than absorption can also be used to form images. Using the Stony Brook scanning transmission X-ray microscope at the National Synchrotron Light Source, high-angle dark-field images have been formed of cells labelled with colloidal gold, with and without silver enhancement. The high density of the colloidal gold particles, or the silver particles seeded by the gold, leads to a large scattering signal, and the fact that the particle diameters are comparable to the width of the microscope point spread function results in good localisation of the label with high contrast. The dark-field images can have a greater signal to noise ratio than bright-field images acquired with the same incident X-ray dose. The theory of dark-and bright-field imaging is reviewed. Theoretical calculations of scattering from gold and silver particles are presented and good agreement is found between these and experimental dark-field images of 30 nm diameter gold particles. The signal to noise ratios of experimental bright-and dark-field images are measured and found to be in agreement with theory. Images are presented of cells labelled by immunolabelling and in situ hybridisation.     

提高铜精矿中金测定的精密度和准确度

研究了铜精矿的粒度分布及各粒级中金含量的赋存规律，发现由于铜精矿的特殊生产工艺，铜精矿的粒度85％集中在－200目，金量的90％也集中在－200目；并从磨样时间和磨样量两个方面试验了铜精矿的加工条件，得出铜精矿中分析测试金的较佳加工条件和加工粒度，加工制成的样品具有均匀性和代表性；从而建立了铜精矿中金的火焰原子吸收快速分析法。该方法操作简便、快速，分析结果稳定、准确，RSD≤4％。     

Demonstration of anionic sites in human eccrine and apocrine sweat glands in post-embedded ultra-thin sections with cationic colloidal gold: effect of enzyme digestion on these anionic sites

We localized anionic sites ultrastructurally in human eccrine and apocrine sweat glands with a poly-L-lysine-gold complex (cationic colloidal gold). Anionic sites were labeled by incubating Lowicryl K4M-embedded sections on droplets of cationic colloidal gold. In eccrine sweat glands, colloidal gold particles were restricted to the basolateral membrane of the secretory cells at low pH, whereas the luminal membrane did not react with the gold particles. Chondroitinase ABC digested these anionic sites. This indicates that chondroitin sulfate and/or dermatan sulfate constitutes anionic sites in the basal labyrinth of eccrine sweat glands. In apocrine sweat glands, the luminal membrane of the secretory cells showed strong reaction at low pH, whereas the contraluminal membrane did not show any reaction. Neuraminidase completely digested these anionic sites, which indicated that the anionic charge of the apocrine lumen was due to sialic acid. Differences in distribution and susceptibility to enzymes of anionic sites in cell membranes between eccrine and apocrine sweat glands may reflect functional differences between these glands. Dark cell granules in eccrine secretory cells were negative for the anionic sites when sections were labeled without any pre-treatment. However, pre-incubation of the grids on EGTA or deionized water unmasked the anionic sites on the dark cell granules. The positive staining after EGTA treatment was greatly decreased by reincubation with CaCl2. These results suggested that Ca blocked anionic sites in dark cell granules. Exposed anionic sites were digested with chondroitinase ABC. This indicated that chondroitinase ABC and/or dermatan sulfate composed the anionic sites in dark cell granules.     

甘肃某金矿浸金工艺试验研究

采用环保型非氰浸金剂,结合全泥炭浆法浸出工艺,对甘肃某金矿的浸金工艺进行了研究。具体考察了溶氧量、矿浆浓度、pH值、矿物粒度、浸金剂用量、浸出温度和浸出时间对金浸出效果的影响,采用原子吸收分光光度计测定原矿和尾矿中的金含量,通过计算金浸出率来确定适宜的浸金工艺条件。结果表明：综合考虑经济和浸出率等因素,在矿浆浓度为40%、pH=11～12、浸金剂用量为300 g/t矿样、浸出温度为20~40 ℃及浸金时间为24 h的条件下,用自来水作溶剂在敞开环境下浸金,浸出效率最佳,金的浸出率可达80％。     

Adsorption of gold on activated carbon in bromide solutions

Adsorption of gold on activated carbon from gold bromide solutions was examined as a function of pH, particle size, amount of carbon, initial gold bromide concentration, bromine concentration, temperature, and various cations and anions. The pH did not have any effect on gold adsorption below pH = 6. Above pH = 6, pH had a dramatically negative effect. The adsorption occurred according to a first-order reaction-rate model. The reaction-rate constant was proportional to the inverse of carbon particle radius, the amount of carbon, and independent of the initial gold concentration. Temperature had very little effect on the rate of gold adsorption. Cations (Cu²⁺, Fe³⁺, Ca²⁺, Mg²⁺, and Na⁺) and anions (SO ₄ ² , Cl^-, Br^-) did not have any effect on gold adsorption. Free bromine had a very negative effect on gold uptake. Gold bromide is very stable and stays in this form on the carbon surface. Contrary to this, gold chloride is unstable, and elemental gold precipitates on the carbon surface. Loading capacity of carbon depended on the presence of free bromine. In the presence of free bromine, it was further dependent on temperature (increased with increasing temperature). AtT = 25 °C, gold loading was 27 to 64 kg Au/t carbon. In bromine-free solutions, gold loading was 174 to 315 kg Au/t carbon.