分散剂在纳米银制备中的影响

采用水热法制备了30 nm左右的纳米银颗粒,分别研究了分散剂的浓度和不同种类的分散剂聚乙二醇、聚乙烯吡咯烷酮、十六烷基溴化铵和聚乙烯醇等在纳米银制备中的影响,结果表明:在此制备纳米银的方法中聚乙烯吡咯烷酮的分散效果最好,颗粒分散均匀,尺寸大小均一。     

The preparation and characterization of novel human-like collagen metal chelates

In order to develop the nutritional trace elements which could be absorbed and utilized effectively, protein chelates were adopted. Calcium, copper and manganese were considered based on their physiological functions, and the new chelates of HLC-Ca, HLC-Cu and HLC-Mn were formed in MOPS or MES buffer and purified by gel chromatography, and then freeze-dried. And they were detected and analyzed by atomic absorption spectrophotometry, ultraviolet–visible absorption (UV–vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, fluorescence quenching method, circular dichroism (CD) and differential scanning calorimetry (DSC). The results showed that some chemical reactions happened between HLC and the three metal ions to form new chemical compounds. The thermodynamic parameters, ?H, ?G and ?S, showed that the chelation process between HLC and metal ions was performed spontaneously. Fluorescence quenching spectra of HLC indicated that the quenching mechanism was static in nature. According to the data of DSC, the new chelates were more stable than the free HLC. And HLC-metal complex was non-toxic to the BHK21 cell through MTT assay.     

超高韧性水泥基复合材料受压性能试验研究

通过对同批次2组圆柱体试件（每组3个）、2组立方体试件（每组3个）进行单轴受压试验,研究龄期、试件类型和纤维类型等因素对超高韧性水泥基复合材料（UHTCC）受压性能的影响,得到UHTCC的轴压应力 应变全曲线及不同类型试件的受压性能规律。结果表明：28 d龄期的圆柱体试件受压时,峰值应变约为0.015,明显高于普通混凝土峰值应变（0.002）;极限压应变为0.034,约为普通混凝土的10倍;7d龄期试件的轴压应力 应变全曲线在应力达到峰值后表现出明显的缓慢下降过程,说明此时UHTCC具有良好的压缩韧性;随着龄期的增长,UHTCC抗压强度提高,但变形能力有所下降;掺入普通高强高模PVA纤维制作的试件抗压强度较高,但变形性能低于K-ⅡREC15型PVA纤维制作的试件;龄期相同时,立方体试件的抗压强度高于圆柱体试件,说明试件尺寸与形状对抗压强度影响较大。     

Phage-based technologies for highly sensitive luminescent detection of foodborne pathogens and microbial toxins: A review

Foodborne pathogens and microbial toxins are the main causes of foodborne illness. However, trace pathogens and toxins in foods are difficult to detect. Thus, techniques for their rapid and sensitive identification and quantification are urgently needed. Phages can specifically recognize and adhere to certain species of microbes or toxins due to molecular complementation between capsid proteins of phages and receptors on the host cell wall or toxins, and thus they have been successfully developed into a detection platform for pathogens and toxins. This review presents an update on phage-based luminescent detection technologies as well as their working principles and characteristics. Based on phage display techniques of temperate phages, reporter gene detection assays have been designed to sensitively detect trace pathogens by luminous intensity. By the host-specific lytic effects of virulent phages, enzyme-catalyzed chemiluminescent detection technologies for pathogens have been exploited. Notably, these phage-based luminescent detection technologies can discriminate viable versus dead microbes. Further, highly selective and sensitive immune-based assays have been developed to detect trace toxins qualitatively and quantitatively via antibody analogs displayed by phages, such as phage-ELISA (enzyme-linked immunosorbent assay) and phage-IPCR (immuno-polymerase chain reaction). This literature research may lead to novel and innocuous phage-based rapid detection technologies to ensure food safety.     

基于遗传算法的属性约简算法研究与实现

本文深入分析了属性约简的方法与算法、遗传算法的基本理论;给出了遗传算法中各类算子的设计和实现方法;提出对编码的改进,即在编码时选择可变长编码;然后用赌轮选择算法对种群中的个体进行选择,很大程度上改进了算法的收敛性能;而且能求得尽可能多的约简,实验证明该算法能对大多数测试数据集求得全部约简.     

臭氧-生物活性炭纤维对苯酚的降解效果研究

采用臭氧-生物活性炭纤维(O3-BACF)工艺对含酚废水的降解效果进行了研究。在臭氧-生物活性炭纤维柱的上、中、下部位分别取样,苯酚的最佳去除率分别为75%、85%和95%左右,下部对苯酚的去除效果最好。采用高效液相分析仪(HPLC)分析了O3-BACF处理过程中苯酚的变化情况,发现经过O3-BACF处理过的苯酚废水产生的中间产物多于O3氧化的。在O3-BACF柱运行的不同时段,研究了膨胀率的变化情况。定期地对O3-BACF装置进行反冲洗再生,以恢复和保持生物活性炭纤维的活性。研究发现反冲洗再生所需的时间很短,再生后的炭柱运行1～2 d后就基本恢复了原来的处理能力。     

玉米秸秆中半纤维素的高效综合利用

Pretreatment of the corn stover powder by dilute sulphuric acid (solid-liquid ratio 1︰20) at 130°C for 30 min was carried out with 89.09% of the hemicellulose removed. After filtration, the xylose-rich corn stover pretreatment liquid, whose fermentable sugar was from hemicellulose hydrolysis only, consisting of 81.16% xylose and 15.27% glucose, was used to cultivate genetic recombinant Escherichia coli BL21 with human-like collagen (HLC) expression enhanced by 50.00% and 63.71% xylose consumption.