精氨酸修饰的磁性纳米基因载体的研究

采用多层修饰方法制备出精氨酸修饰的磁性纳米基因载体,对样品进行了粒度分析、Zeta电位分析、耐酸性能、生物相容性、体外细胞转染性能研究。结果显示,精氨酸修饰的磁性纳米颗粒均匀,分散性好,大多呈圆球型,平均粒径为15 nm,粒径范围10~20 nm,其Zeta电位为+29.3 mV;多层修饰的纳米磁粒在pH 2.0的酸中具有很好的耐酸性能,而未处理的纳米粒子在酸溶液中发生了溶解。MTT实验结果显示,纳米颗粒与细胞有良好的生物相容性;体外细胞转染的结果表明,精氨酸修饰的纳米磁粒能介导pEGFP-N1质粒转染HepG2细胞,并在细胞中表达绿色荧光蛋白。因此,精氨酸修饰的磁性纳米颗粒作为一种新型非病毒基因载体具有介导核酸类生物大分子的应用价值。     

有机硅浆渣水解废料资源化综合利用

对氯硅烷合成过程中产生的有机硅浆渣水解废料进行了资源化综合利用。针对水解废料的特性，设计了提铜、提硅粉及溶解制备甲基硅树脂微粉的工艺，分析了浆渣水解废料中主要成分含量的变化，探究了溶解温度、碱投入量及反应时间对溶解度的影响，最后将溶解液制成甲基硅树脂微粉，并对其形貌、粒径及杂质残留量进行了表征。结果表明：经过提铜提硅单质工艺，浆渣水解废料中铜的提取率约为91.43%,单质硅的提取率约为74.51%;在溶解条件为温度120℃、碱质量分数25%(占浆化脱铜脱硅水解渣质量的百分比)及反应60 min时，活化后的浆渣水解废料溶解度可达90.23%,综合利用率约为93.68%;此外，利用除杂溶解液制备的甲基硅树脂微粉产品经表征为20～50 nm球状颗粒组成的平均粒径为2μm的附聚体粉末，其Fe和Cu元素杂质残留量分别为102.81 mg/kg、9.12 mg/kg。     

表面活性剂(PVA)浓度对电子束制备纳米铜的影响

在水溶液中,常温常压下使用聚乙烯醇(PVA)为表面活性剂,用电子束辐照方法可以成功制备纳米铜粉。利用紫外可见分光光度计(UV)和激光粒度衍射仪(LSPSDA)考察了表面活性剂浓度对纳米铜粒径分布和团聚的影响。在一定范围内随着PVA浓度的增大纳米铜的粒径减小到13nm。X射线衍射(XRD)和透射电子显微镜(TEM)结果表明PVA浓度为0.88g/100mL,pH值在5~9之间时,能得到纯的纳米铜,其粒径分布为15~40nm。     

加料顺序对两种盐溶解性的影响

盐的溶解及盐效应的研究对化工技术开发具有重要意义。采用平衡法,常压下,测得了对苯二甲酸二钠在不同温度下于水中的溶解度。在常压和298.15 K下,考察了对苯二甲酸二钠等7种有机盐和无水硫酸钠等3种无机盐在水中的两两溶解过程,发现加料顺序会影响两种盐的溶解性。得到如下结果:先溶解难电离的盐再溶解易电离的盐,则后者的溶解速度变化不明显;而先溶解易电离的盐再溶解难电离的盐,则后者的溶解速度会显著降低且溶解度变小。将其中一种盐的量固定后,在一定时间内另一种盐所能溶解的量定义为准溶解度。测定了对苯二甲酸二钠在不同浓度的柠檬酸三钠水溶液中的准溶解度,为相关化工行业的产品分离纯化提供依据。     

空气氧化酸浸法生产硫酸铜

天津市物资回收公司熔炼厂在用铜毛丝制取硫酸铜(CuSO_4·5H_2O)过程中,采用直接空气氧化酸浸法取代原用炉反射焙烧氧化酸浸法,缩短了工艺流程,节约了原材料和燃料,提高生产效率一倍以上。一、空气氧化酸浸原理金属铜—废铜毛丝,在稀硫酸中不能直接溶解,鼓入空气后,空气中的氧将铜毛丝氧化     

高品质RDX在DNAN中的溶解及反复熔融特性研究

为研究高品质RDX在2,4-二硝基苯甲醚(DNAN)中的溶解及反复熔融特性,采用高效液相色谱法研究了高品质RDX在DNAN中的溶解度及影响因素;通过工艺试验研究了DNAN/高品质RDX熔铸炸药在反复熔融后的不可逆增稠特性;运用热台显微装置研究了高品质RDX在DNAN中的溶解及析出过程,并与普通RDX(3类)进行了对比。结果表明,随着高品质RDX粒度的增大,其在DNAN中的溶解度逐渐减小,呈近似线性关系;高品质RDX在DNAN中的溶解度随温度升高而增大,115℃时高品质RDX(d50=470μm)在DNAN中的最大溶解度达到8.87g/100g,在不同温度下溶解度均小于普通RDX;DNAN/高品质RDX配方在反复熔融后的不可逆增稠程度小于DNAN/普通RDX配方;高品质RDX在DNAN中的溶解首先从晶粒的不规则外沿和晶体凹陷区域开始,溶解速率受颗粒尺寸及不规则程度影响,且明显慢于普通RDX;析出存在两种方式且析出后形状呈不规则变化。     

片状氢氧化镁晶种的制备研究

研究了在极稀溶液中制备氢氧化镁晶种时,反应物用量、pH值、分散剂等因素对所制备的氢氧化镁晶种的晶体结构、形态及粒径的影响。用X-射线衍射仪（XRD）表征晶体结构,晶种在体系中的分散性及粒径大小由纳米粒度及电位分析仪来表征,通过透射电镜（TEM）观测晶体形貌。最终制得了粒径约为4．5nm左右的片状结构的氢氧化镁晶种。     

载体对甲维盐固体纳米制剂的性能影响

为了研究载体对农药固体纳米制剂理化性能的影响及其选择原则，采用自乳化-载体固化法制备了7种不同载体的甲氨基阿维菌素苯甲酸盐（甲维盐）固体纳米分散体。比较了载体粉末粒度、溶解度、比表面积及形貌间的差异性，揭示了不同载体对甲维盐固体纳米分散体粒径、分散度、界面电荷、pH、晶型及叶面润湿性的影响。结果表明，农药固体纳米分散体中载体的理化性质及结构对纳米制剂的粒度、分散性、界面性质及晶型具有显著影响。苯甲酸钠为甲维盐固体纳米分散体的优良载体，载药粒子的平均粒径为22 nm，PDI为0.358。     

基于动态光散射下纳米二氧化硅分散性的影响因素研究

纳米二氧化硅是目前应用最为广泛的一种纳米材料,但其团聚行为对粒径测量和应用效果有不利的影响。为减少纳米二氧化硅颗粒的团聚行为,应用动态光散射粒度分析方法,考察了分散方式、分散剂种类、悬浮液条件对不同纳米二氧化硅的粒径及多分散性指数（PDI）的影响规律。实验结果表明,磁力搅拌条件下,0.1%（质量分数）的PEG-2000对各类纳米二氧化硅均具有较好的分散效果;随着悬浮液pH增大,硅溶胶悬浮液粒径和PDI均呈下降趋势,是因为悬浮液pH影响了硅溶胶的溶解平衡;而固态二氧化硅悬浮液的粒径和PDI则呈先上升后下降的趋势,这是由于悬浮液pH影响了双电层结构。实际测试和应用中应注意悬浮液配制条件和纳米二氧化硅类别对粒径和PDI的影响。     

黄芩甙纳米乳的制备

研制了黄芩甙纳米乳并对其进行了质量评价。通过绘制伪三元相图优选处方,以肉豆蔻酸异丙酯(IPM)、液体石蜡和维生素E油为油相,蓖麻油聚氧乙烯醚(EL-40)为表面活性剂,乙醇为助表面活性剂制备黄芩甙纳米乳,用透射电子显微镜(TEM)、Nicomp388/ZetaPALS激光粒度测定仪分别考察了其形态和粒径;通过恒温加速实验检验了其稳定性。黄芩甙纳米乳在透射电镜下呈圆球形,分布均匀,平均粒径为(35.3±0.27)nm,恒温加速实验结果显示其未分层,仍为澄清透明纳米乳状液。纳米乳质量稳定,能提高黄芩甙的溶解度,且有很好的皮肤渗透性,提高了化妆品在皮肤上的延展性,可望用作皮肤化妆品基质。     

不同粒度纳米碱式碳酸铜的制备

以五水硫酸铜和碳酸钠为原料,采用直接沉淀法研究了纳米碱式碳酸铜的制备,考察了反应温度、反应物的浓度对其粒径的影响。结果表明,当反应温度在45～75℃,反应浓度在1～2.5 mol/L时,可以制备出不同粒径的纳米碱式碳酸铜,其平均粒径范围为16～54 nm;纳米碱式碳酸铜的粒度随反应温度的升高而减小,随反应物浓度的增大而增大。     

Optimum performance data for the leaching of roasted chalcopyrite concentrate in a jet contactor

Chalcopyrite concentrate has been roasted in a mullite tube furnace and the optimum temperature of roasting determined. The roasted concentrate has been leached with dilute sulphuric acid in a jet contactor. Optimum performance data for leaching, namely temperature, particle size, slurry concentration, acid concentration, nozzle diameter and effective contactor height have been obtained. For predicting the copper concentration in the leached solution, an expression based on a diffusion model has been derived and compared with the experimental data. It has been observed that at low values of mixed phase velocity, the agreement is good, but at high values, the variation is relatively larger.     

不同粒度纳米碳酸钙的可控制备

不同粒度的纳米碳酸钙具有不同的特性和应用范围,目前不同粒度纳米碳酸钙的可控制备方法还未见报道。以氯化钙、碳酸铵为原料,以乙醇、柠檬酸和焦磷酸钠为分散剂,采用复分解法研究了不同制备条件对纳米碳酸钙粒径的影响规律,在此基础上制备出平均粒径为17~71 nm的碳酸钙,并对其进行了表征。实验结果表明,所制备的纳米碳酸钙均为球霰石型,纯度很高,而且形貌近似球形。制备条件对纳米碳酸钙的粒径有显著的影响：随着反应温度升高,纳米碳酸钙的粒径减小;随着氯化钙滴加时间的增加,纳米碳酸钙的粒径增大;随着反应物浓度的提高,纳米碳酸钙的粒径先减小后增大;当分散剂为柠檬酸和焦磷酸钠的混合溶液时所得纳米碳酸钙的粒径最小,当分散剂为乙醇和焦磷酸钠的混合溶液时所得纳米碳酸钙的粒径最大。利用这些影响规律通过控制制备条件可以实现所需粒径纳米碳酸钙的可控制备。     

70%H2SO4回硫酸生产系统提浓的操作与控制

稀硫酸腐蚀性强,硫酸法-浓硝酸工艺采用98%H2SO4脱除硝酸中的水,产生了大量的稀硫酸须予以处理.介绍了用稀硫酸作为硫酸生产装置干吸工序补充水,在提浓的同时又提高了装置的硫酸产量,提出了使用稀硫酸时的操作程序和应注意的问题.     

Analytic and numerical calculations of the formation of a sulphuric acid aerosol in the upper troposphere

Analytic and numerical calculations are performed on the production of sulphuric acid aerosol in conditions of a very large nucleation event observed in the upper troposphere. The numerical results feature a growing peak in the size distribution whose magnitude is reproduced well analytically, and are consistent with the observed particle number concentration at sizes greater than 25 nm (measured dry diameter), but suggest that most of the aerosol was at unobserved smaller sizes. Because of growth and coagulation, number concentrations of the aerosol rapidly become independent of the number initially nucleated, so that conclusions as to the nucleation process, either homogeneous or ion-induced nucleation, cannot easily be drawn from existing atmospheric observations. The final concentration is very insensitive to the magnitude of the SO₂ source, but, if condensation on, and coagulation with, a remnant background aerosol occurs, such nucleation events will be cut off for source magnitudes less than a specific value. Anthropogenic emissions of SO₂ which exceed this value can produce higher aerosol number concentrations in the atmosphere with consequences for the indirect effect of aerosols on the climate.     

常温下微细化淀粉的制备

利用硫酸水解的方法。在常温情况下制备微细玉米淀粉颗粒。结果表明：在20℃条件下用浓度为4mol／L的硫酸,反应72h,水解效果最好。通过控制反应条件。研究了盐酸、硫酸浓度、反应时间对淀粉颗粒平均粒径的影响,并优化反应工艺条件。     

Viscosity of Electrostatically Stabilized Dispersions of Monodispersed, Bimodal, and Trimodal Silica Particles

Effect of particle size and polydispersity on the viscosity and maximum packing fraction of aqueous colloidal dispersions has been studied. For dispersions of mono-sized particles, the results indicate that there is a linear relationship between the log(η) (viscosity) and particle size at a fixed shear rate and volume fraction of solids. However, there is a particle diameter at which there is a decrease in the dependency of viscosity on particle size as the slope of the linear plots of log(η) versus particle diameter changes to a smaller value. Preliminary calculations indicate that this particle size may correspond to a separation distance at which electrostatic energy as compared with the thermal energy of the particles can be ignored. In the case of bimodal dispersions, the viscosity is affected by both absolute size and the ratio of the two sizes. The effect of particle size ratio on the viscosity was investigated using bimodal dispersions of the same size coarse particles, but fines of different sizes. There is a critical volume ratio below which bimodal dispersions of larger size ratios show lower viscosities than systems of smaller size ratios. Above this volume ratio of the two sizes, the trend becomes reversed and the fines will have a dominant effect on the viscosity behavior of the bimodal system. Statistically designed experiments were carried out using trimodal mixtures of monodispersed silica particles and it was shown that tridispersed suspensions demonstrate similar behavior as bidispersed suspensions, with a minimum in viscosity observed as a function of particle volume ratio.     

对安赛蜜生产中回收催化剂工艺的改进

以氨基磺酸、双乙烯酮、三乙胺、三氧化硫、冰醋酸为原料,经乙酰乙酰化、环合、水解、成盐4步反应合成安赛蜜的过程中,会产生一定量的含稀硫酸的溶液。其组分主要为稀硫酸,含有少量三乙胺硫酸盐、丙酮等。生产过程中对三乙胺的回收,对产生的稀硫酸进行中和和对稀酸中约含5%左右的三乙胺硫酸盐回收显得十分重要,这不仅是从经济效益上进行考虑,更是环保要求的需要。通过对安赛蜜生产中回收催化剂工艺进行改进后,不仅能消除碱化解析三乙胺硫酸盐过程中用生石灰粉造成的粉尘污染,又能提高合成安赛蜜过程中三乙胺回收率。     

Processing of Soot by Controlled Sulphuric Acid and Water Condensation—Mass and Mobility Relationship

The effects of atmospheric processing on soot particle morphology were studied in the laboratory using the Differential Mobility Analyzer-Aerosol Particle Mass Analyzer (DMA-APM) and the DMA-DMA (Tandem DMA) techniques. To simulate atmospheric processing, combustion soot agglomerates were altered by sulphuric acid vapor condensation, relative humidity (RH) cycling, and evaporation of the sulphuric acid and water by heating. Primary investigated properties were particle mobility size and mass. Secondary properties, derived from these, include effective density, fractal dimension, dynamic shape factor, and the mass fraction of condensed material. A transformation of the soot particles to more compact forms occurs as sulphuric acid and water condense onto fresh soot. The particle mass increases and initially the mobility diameter decreases, indicating restructuring of the soot core, likely due to surface tension forces. For a given soot source and condensing liquid, the degree of compaction depends strongly on the mass (or volume) fraction of condensed material. For water and sulphuric acid condensing on combustion soot, a mass increase of 2–3 times is needed for a transformation to spherical particles. In the limit of spherical particles without voids, the effective density then approaches the inherent material density, the fractal dimension approaches 3 and the dynamic shape factor approaches 1. Our results indicate that under typical atmospheric conditions, soot particles will be fully transformed to spherical droplets on a time scale of several hours. It is expected that the morphology changes and addition of soluble material to soot strongly affect the optical and hygroscopic properties of soot.     

Characterization and conformation of aromatic polyamides: poly(1,4-phenylene terephthalamide) and poly(p-benzamide) in sulphuric acid

The dilute solution properties of two aromatic polyamides, poly(1,4-phenylene terephthalamide) (PPDT) and poly(p-benzamide) (PBA) in 96% sulphuric acid, have been investigated by measurements of the intrinsic viscosity, by light scattering and by gel permeation chromatography (g.p.c.). The Mark—Houwink relation for PPDT indicates that the conformation is intermediate between a coil and a rod-like particle. The conformations of both aromatic polyamides have been determined precisely by coupling g.p.c., light scattering and viscosity and it was found that PPDT and PBA in 96% sulphuric acid are not very rigid particles. The rigidity has been characterized in terms of a worm-like chain. The persistence lengths q which evaluate the rigidity of the chain are $\text{q = 175 ± 25}\text{A}\text{?}$ for PPDT and $\text{q = 500 ± 100}\text{A}\text{?}$ for PBA has the more rigid polymer chain.