含有金纳米粒子的复合纳米纤维的制备和表征

以氯金酸(HAu Cl4)为原料,柠檬酸钠(C6H5Na3O7·4H2O)为还原剂,聚乙烯吡咯烷酮(PVP)为保护剂,乙醇为溶剂制备出含有金纳米粒子的溶胶溶液;采用高压静电纺丝技术制备了含有金纳米粒子的聚乙烯吡咯烷酮复合纳米纤维。通过紫外光谱研究了不同含量的金纳米粒子对纤维吸光度的影响;通过扫描电子显微镜和透射电子显微镜考察了含有金纳米粒子的聚乙烯吡咯烷酮复合纳米纤维的形貌。研究表明,随着金纳米粒子在纺丝溶液含量的增大,金纳米颗粒的特征吸收峰越来越明显,且有红移趋势;随着金纳米颗粒的增多,纤维逐渐变细,浓度过高时则不能生成纤维。     

纳米金的制备及其对体外培养细胞生长的影响研究

目的合成粒径均一、高生物亲和力的纳米金颗粒(gold nanoparticles;GNPs),评价其对体外细胞生长的影响。方法以4-羟乙基哌嗪乙磺酸(HEPES)为还原剂合成GNPs,通过紫外光谱分析(UV)及透射电镜(TEM)进行表征。研究不同浓度(0、5、10、15、20及25μg/m L)的GNPs对鼠成纤维细胞(L-929)的生长影响。倒置显微镜观察各组细胞形态变化,MTT比色法测定溶液吸光度值来评估细胞毒性,细胞内活性氧(ROS)检测试剂盒测定GNPs对L929细胞内活性氧含量的影响。结果浓度2.5×10-5mmol/L氯金酸与浓度1.0×10-2mmol/L HEPES体积比100∶1,加热沸腾下合成的纳米金溶液呈透亮的酒红色,UV结果显示紫外特征峰在525 nm,TEM表征表明该方法制备的GNPs为球型,平均直径约为24 nm,粒径较均一,有良好的稳定性与分散性。细胞实验显示各组细胞ROS水平随着培养基中GNPs含量的升高而降低,当GNPs浓度20μg/m L时,参考《体外细胞毒性试验标准》(ISO-10993-5),其细胞毒级为0~1级,具有良好的生物相容性。结论成功合成了粒径均一且具有高生物亲和力的GNPs。     

柠檬酸对聚硅酸聚合氯化铁的制备及性能影响

柠檬酸加入到聚硅酸聚合氯化铁溶液中,对其进行Ferron逐时络合实验、混凝实验、透射电镜实验等,研究其对PSPFC性能的影响,实验结果表明柠檬酸的加入对PSPFC的混凝效果影响显著,浊度显著降低,稳定性得到提高,因此引入柠檬酸根离子是有利的。     

氟金云母玻璃陶瓷粉体的溶胶凝胶法制备

以Mg(NO_3)_2·6H_2O、Al(NO_3)_3·9H_2O、NH_4F、NaF、CO(NH_2)_2和硅溶胶为原料,采用溶胶凝胶法制备氟金云母(NaMg_3AlSi_3O_(10)F_2)。借助X射线衍射(XRD)、同步热分析(DTA/TG)、场发射扫描电镜(FESEM)和透射电镜(TEM)等检测手段,研究了热处理温度等因素对氟金云母粉体晶相组成和晶体生长情况的影响。研究结果表明:合成粉体的物相具备典型的玻璃陶瓷材料特征,粉体直径约为30 nm。晶化热处理后粉体晶态比例显著提高,呈现尺寸较大的片状形貌。氟金云母晶相在500℃开始明显析出,随着晶化温度的适当提高,氟金云母的晶化速度显著提高,杂相也明显减少。     

溶胶—凝胶TiO2多元系统的锐钛矿一金红石相变

研究了溶胶－凝胶ＴｉＯ２－ＳｉＯ２,ＴｉＯ２－ＺｒＯ２,ＴｉＯ２－ＳｉＯ２－ＺｒＯ２多元系统锐钛矿－金红石相变,用ＸＲＤ,ＦＴＩＲ,ＤＴＡ等方法研究不同温度下各系统的结晶特征和锐钛矿一金红石相变温度,与一般固相反应不同,溶胶－凝胶ＴｉＯ２多元元系统可以在一定组成范围内形成不同固溶度的锐钛矿相纳米晶,不同组成的锐钛矿相纳米晶,可以导致颗粒度变化,以及锐钛矿一金红石相变温度的变化。     

溶胶-凝胶TiO2多元系统的锐钛矿-金红石相变

研究了溶胶凝胶TiO2SiO2,TiO2ZrO2,TiO2SiO2ZrO2多元系统锐钛矿—金红石相变,用XRD,FTIR,DTA等方法研究不同温度下各系统的结晶特征和锐钛矿—金红石相变温度.与一般固相反应不同,溶胶凝胶TiO2多元系统可以在一定组成范围内形成不同固溶度的锐钛矿相纳米晶.不同组成的锐钛矿相纳米晶,可以导致颗粒度变化,以及锐钛矿—金红石相变温度的变化     

玉米粉液化条件对柠檬酸发酵的影响

本文只要介绍了玉米粉液化条件对柠檬酸发酵的影响,玉米经过粉碎后,进行调浆、液化、添加菌种发酵生产柠檬酸,其中玉米粉碎粒度的大小、液化温度、液化时间、液化起始pH值、液化加酶量均对柠檬酸发酵具有较大的影响。     

柠檬酸和柠檬酸铵对氯氧镁水泥水稳定性的改善机理EI北大核心CSCD

以轻烧MgO和MgCl_(2)·6H_(2)O为主要原料,同时掺加少量柠檬酸或柠檬酸铵,制备了氯氧镁水泥(MOC),研究了柠檬酸和柠檬酸铵对MOC水稳定性的改善作用及其作用机理.结果表明:柠檬酸根离子与MgOH^(+)结合形成了有机镁络合层,在阻碍Mg(OH)_(2)产生的同时,促进了5Mg(OH)_(2)·MgCl_(2)·8H_(2)O(5-1-8相)的生成,提高了MOC试件各龄期的抗压强度和体积稳定性;引入柠檬酸和柠檬酸铵没有生成新相,但柠檬酸根离子吸附在5-1-8相表面,显著提高了MOC的水稳定性,并且柠檬酸对MOC水稳定性的改善效果要优于柠檬酸铵.     

CdS敏化TiO_2纳米管的制备和性能研究

采用联系离子层沉积法,在透明的TiO2纳米管阵列薄膜上沉积CdS,制备CdS敏化TiO2纳米管阵列薄膜光阳极材料。通过改变沉积液的溶剂和控制沉积次数,研究不同量的CdS对TiO2纳米管薄膜的光电性能的影响。结果表明,在以乙醇、甲醇/水为溶剂的条件下,循环沉积4次后制备的CdS/TiO2光阳极表现最好的光电转换效率。     

黄铁矿中晶格金、自然金、石英包体金的分离技术及测试方法

本文以铜陵地区黄铁矿为例,对黄铁矿中晶格金、自然金、石英包体金的分离技术和测试方法进行分析,其结果可用于研究载金矿物黄铁矿中的不同状态金与成矿之间的关系。     

Effect of periodic feeding on substrate uptake and storage rates by a pure culture of Thiothrix (CT3 strain)

A pure culture of Thiothrix strain CT3 has been aerobically cultured under periodic acetate feeding in a Sequencing Batch Reactor (SBR) at volumetric organic load rate of 0.12gCODL(-1)d(-1). Two different culture residence times (12d or 20d) were adopted as well as two different feed frequencies (1 and 4d(-1), for each culture residence time), the volumetric organic load rate being the same under all conditions. The transient response of the microorganism to the periodic acetate feed was investigated through batch tests with biomass withdrawn from the SBR, as function of the different SBR operating conditions. In all tested conditions, a quick transient response to the acetate spike was observed with fast increase of acetate uptake rate (ranging from 71 to 247mgCODgCOD(-1)h(-1)). This transient response was mainly due to acetate storage in form of poly-hydroxybutyrate (ranging from 45% to 64% of the observed yield) whereas the growth response (i.e. increase of production rate of active biomass) generally played a minor role (ranging from 21% to 38% of the observed yield). Apart from this general trend, culture residence time as well as feed frequency had a strong impact on transient behaviour of cultured cells. The overall transient response (i.e. maximum specific substrate removal rate) increased as culture residence time decreased or as feed frequency increased. Moreover, the ratio of storage response and growth response increased as the overall transient response decreased, i.e. the storage response was preferentially maintained when cells presented a lower transient response. The ability of the cells to increase their growth rate with respect to SBR average value was the lowest under the most unfavourable conditions (residence time 20d, feed frequency 1d(-1)) and increased with the increase in maximum substrate uptake rate.     

Effect of periodic feeding in sequencing batch reactor on substrate uptake and storage rates by a pure culture of Amaricoccus kaplicensis

A pure culture of Amaricoccus kaplicensis was aerobically cultured at a long culture residence time (Theta(C)>12d), under periodic acetate feeding in a sequencing batch reactor (SBR). The cycle length and, correspondingly, the volumetric organic load rate (vOLR) were varied in the range 4-24h and 0.76-0.12gCODl(-1)d(-1), respectively. The transient response of the microorganism to the acetate spike was investigated throughout batch tests, as a function of SBR cycle length and vOLR. In all tested conditions, a rapid transient response was observed, mainly due to acetate storage in the form of polyhydroxybutyrate, since growth (production of active biomass) played a minor role. Apart from this general trend, the maximum rates under transient conditions increased as the cycle length increased from 4 to 24h. In the SBR, the longest cycle also caused a decrease in floc size and settleability as well as an increase in the observed yield. The observed effect of SBR operating conditions on the physiological state of cells and their related transient response may have great significance on the performance of full scale activated sludge processes.     

缝高比对碾压混凝土名义断裂韧度的影响

对不同缝高比的碾压混凝土试件进行了楔入劈拉试验,通过对名义断裂韧度试验结果进行分析,得到缝高比对碾压混凝土的断裂韧度的影响规律。将碾压混凝土断裂韧度试验结果与已有的混凝土断裂韧度尺寸效应公式及基于Hu公式得到的断裂韧度尺寸效应公式结合,确定了碾压混凝土名义断裂韧度在缝高比这一因素影响下的公式。     

Influence of substrate on fire performance of wall lining materials

This study assessed the fire risk of attaching a qualified surface wall lining to an unqualified combustible substrate. Experimental materials were gypsum, magnesium oxide, calcium silicate board and fire-retardant plywood, which were attached to a non-fire-retardant plywood panel. The CNS 6532 Surface Test and the ISO 5660 Cone Calorimeter Test were applied. The former simulates the heating environment in the early fire stage and the latter simulates a fully developed fire. Experimental data show that when a qualified surface material was attached to a non-qualified substrate, the temperature rise in the Surface Test decreased. The substrates consequently enhance fire safety performance in the early stage of fire growth mainly due to crake prevention and a decrease in the amount of heat stored in surface materials for subsequent ignition. Additionally, the heat release rate in the Cone Calorimeter Test increased or decreased when a qualified surface material was attached to a non-qualified substrate. Therefore, the existence of substrates enhances or reduces a material’s combustibility rank when a fire is fully developed. The key mechanism is the crake or flame penetration of surface wall lining, which can lead to substrate ignition. The change of combustibility rank depends on the time at which a crake develops or flames penetrate a substrate.     

结晶器铜板超音速火焰喷涂工艺参数对涂层结合强度的影响

文中采用超音速火焰喷涂(HVOF)在结晶器铜板表面喷涂了CoNiCrAlY涂层,研究了喷涂主要工艺参数对涂层结合强度的影响。结果表明:涂层的结合强度随着燃油流量的增大而显著增大,随着氧气流量与喷涂距离的增加结合强度均出现先增加后下降趋势,喷砂后较未喷砂结合强度大大提高。选择合适的粉末形状与粒径对于获得高质量的涂层较为重要。     

粉煤灰的新型化学激发及低碱混凝土配合比研究

根据绿色植被混凝土中植物生长对混凝土碱度的要求,采用新型酸性激发剂X激发粉煤灰活性,制备高掺量粉煤灰混凝土;并以化学方法进行降碱处理,制备出低碱混凝土。探索新型酸性激发剂X激发粉煤灰活性的最优工艺、碱度的降低方法,为制备绿色植被混凝土奠定了物质基础。     

Influence of substrate on fouling in anoxic immersed membrane bioreactors

The influence of carbon substrate chemistry on membrane bioreactor (MBR) fouling in anoxic conditions has been evaluated. The use of a weak carboxylic acid (acetic acid) resulted in the production of large open-floc structures (up to 508microm) that were susceptible to breakage. Primary particles (d(10) and d(20) particle sizes, 5.5+/-1.3 and 15.3+/-8.2microm, respectively) and macromolecular soluble microbial products (SMPs) were generated, directly impacting on membrane fouling. The use of a primary alcohol (ethanol), on the other hand, encouraged the growth of flocs similar to activated sludge. These flocs produced low concentrations of primary particles (d(10) and d(20) particle sizes, 120.6+/-36.1 and 185.2+/-62.7microm, respectively) and high-molecular-weight SMP, and the particles had sufficient mechanical integrity to withstand shear. Consequently, the use of ethanol resulted in sufficient suppression of fouling to extend the filtration time by a factor of three. An increase in MLSS concentration did not directly impact upon fouling when operating with ethanol, primarily because of the low concentration of particulate matter produced.     

浅谈采用工程量清单报价方式提高中标率

简述了工程量清单报价的应用，从工程量清单的分析、报价组成的确定、投标策略的采取、内部定额的编制介绍了采用工程量清单进行报价的方法，以提高中标率。     

复合膨胀剂限制膨胀率检测方法

配方确定了复合膨胀剂限制膨胀率的检测方法,在实际工作中进行应用,取得良好效果。     

用一元线性回归分析法选择配制水灰比

对用一元线性回归分析法来选择配制水灰比进行了研究，并且进行了实例分析，以推广一元线性回归分析法的应用，使水泥混凝土配合比设计更科学、更准确。