新疆某铀矿酸法和CO_2地浸采区地下水的污染特征及机理

为研究酸法和CO_2地浸采铀对地下水的影响,对新疆伊犁盆地的酸法和CO_2地浸采区的地下水水质进行采样分析。结果表明,酸法地浸开采时地下水中绝大部分组分含量均明显高于地下水本底值和国家地下水Ⅲ类质量标准,总矿化度超过国家地下水Ⅲ类标准11倍左右,超标的组份主要有硫酸根、锰、镍、铁、铅、锌、镉、砷等重金属元素和钍等放射性元素。CO_2地浸对地下水各个组分浓度影响要小得多,pH基本不变,总矿化度高出国家地下水Ⅲ类质量标准2.6倍左右,地下水中主要的污染因子为硫酸根离子、硝酸根离子、氯离子、锰离子和镍离子,而铜、锌、镉、铅、铁、砷等其它组分浓度未发生显著变化。酸法采区中的单项污染指数依次为FeMnNiPbSO_4~(2-)ZnAsCd,CO_2采区中单项污染指数依次为NO_3~-MnNiSO_4~(2-)Cl~-。酸法采区地下水综合污染指数比CO_2采区高3～384倍。污染物主要来源于人为注入的化学试剂和含矿层中矿物反应释放的组分,两种地浸方法由于加入的溶浸剂不同导致地下水的地球化学环境和污染特征存在显著差异。     

分析化学网络智能组卷系统的开发

为了进一步推动教学改革,促进教学质量的提高,我们开发了分析化学智能组卷系统,介绍了智能组卷系统开发的意义、开发过程、主要特色及使用效果,并对开发前景进行了展望。结果表明:该网络智能组卷系统具有客观性强、时间快、易于控制试卷难度等特点,深受师生和专家好评。     

无机化学实验教学绿色化探索与实践

基于绿色化学的理念,就如何实现无机化学实验的绿色化进行了探索和研究。提出了推行微型化学实验、多媒体仿真技术、"三废"处理、串联实验和现代检测技术应用于无机化学实验中。通过以上措施,加强和培养了师生的环境保护意识,树立了绿色化学的理念。同时,无机化学及实验的绿色化节约了化学试剂,减少有毒有害物质的排放,实现了环境友好化过程。     

Adsorption‐concentration polarization model for ultrafiltration in mixed matrix membrane

Adsorption has been found to be significant in ultrafiltration by mixed matrix membrane. Removal of very low molecular weight solutes compared to the molecular weight cut off of the membrane is facilitated by adsorption. The modeling of the adsorption coupled with concentration polarization is presented based on the mathematical approach developed by Gekas et al. (Gekas et al. Chem Eng Sci. 1993;48:2753–2765), from the first principles. However, extensive modifications were included in theoretical development including those suggested by Ruiz‐Bevia et al. (Ruiz‐Bevia et al. Chem Eng Sci. 1997;52:2343–2352). The developed model captured the rejection dynamics with the help of retention factor. The model equations were solved under the framework of boundary layer analysis, using the integral approach. Effects of the adsorption isotherm and the different parameters affecting the system performance were also investigated. Further, experimental validation of the model results with two different mixed matrix ultrafiltration studies was also elucidated. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2354–2364, 2014     

Tough hyperbranched epoxy/poly(amido‐amine) modified bentonite thermosetting nanocomposites

A tough and highly flexible hyperbranched epoxy and poly(amido‐amine) modified bentonite based thermosetting nanocomposite was demonstrated. The FTIR, XRD, and TGA analyses confirmed the modification of bentonite. The formation of partially exfoliated structure of the nanocomposite with good physicochemical interactions among the hyperbranched epoxy, poly(amido‐amine) hardener and modified clay was investigated by the FTIR, XRD, SEM, and TEM analyses. Significant improvements of 750% toughness, 300% elongation at break, 50% tensile strength, 300% modulus, and 250% adhesive strength of the pristine epoxy were achieved by the formation of nanocomposites with 3 wt % of modified clay. The experimental modulus values of the nanocomposites were compared with three theoretical models to account the interactions between filler and matrix. Thus, the studied epoxy nanocomposite has great potential to be used as an advanced epoxy thermoset. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40327.     

How Different Characterization Techniques Elucidate the Nature of the Gold Species in a Polycrystalline Au/TiO2 Catalyst

TiO₂‐supported gold species were prepared via the deposition‐precipitation route, with conservation of the initial speciation by freeze‐drying. The structural and electronic properties of the Au species were investigated by X‐ray absorption spectroscopy, electron microscopy, and IR spectroscopy of adsorbed CO in four states. Exclusively Au^III was deposited on the TiO₂ surface in patches ranging from isolated Au ions to three‐dimensional clusters. This paper illustrates in detail the unique contributions of all characterization techniques to this structural model.     

Regenerated cellulose nanocomposites reinforced with exfoliated graphite nanosheets using BMIMCL ionic liquid

Green nanocomposites of regenerated cellulose/exfoliated graphite nanosheets films with low nanofiller loadings were prepared using environmentally benign 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid. X-ray diffraction revealed well developed intercalated nanocomposites. The tensile strength and Young's modulus of the prepared nanocomposites were increased by 97.5% and 172% respectively when 0.75 wt.% and 1 wt.% exfoliated graphite nanosheets were added. The results were validated using the Halpin–Tsai model. The exfoliated graphite nanosheets were unidirectionally aligned in the regenerated cellulose parallel to the surface of the nanocomposites as revealed by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Also, the TEM and FESEM revealed uniform dispersion of the exfoliated graphite nanosheets and good interaction between the nanofillers and the matrix. The addition of the exfoliated graphite nanosheets enhanced the thermal stability and reduced the water absorption and diffusivity of the nanocomposites.     

高效液相色谱法同时测定多种杀虫剂的有效成分

建立了用高效液相色谱法测定农药市场上常见的8种杀虫剂及2种禁限用农药有效成分的分析方法。采用C18柱(150L×4.6mm),以乙腈-水为流动相,紫外检测器检测,外标法定量。结果表明,样品的加标回收率为90.0%¹02.0%,相对标准偏差为0.01%102.0%,相对标准偏差为0.01%¹.47%。该方法简单、快速、结果准确,可作为单剂、复配制剂同时测定其有效成分的方法。     

Tracking the Molecular Fingerprint of Head and Neck Cancer for Recurrence Detection in Liquid Biopsies

The 5-year relative survival for patients with head and neck cancer, the seventh most common form of cancer worldwide, was reported as 67% in developed countries in the second decade of the new millennium. Although surgery, radiotherapy, chemotherapy, or combined treatment often elicits an initial satisfactory response, relapses are frequently observed within two years. Current surveillance methods, including clinical exams and imaging evaluations, have not unambiguously demonstrated a survival benefit, most probably due to a lack of sensitivity in detecting very early recurrence. Recently, liquid biopsy monitoring of the molecular fingerprint of head and neck squamous cell carcinoma has been proposed and investigated as a strategy for longitudinal patient care. These innovative methods offer rapid, safe, and highly informative genetic analysis that can identify small tumors not yet visible by advanced imaging techniques, thus potentially shortening the time to treatment and improving survival outcomes. In this review, we provide insights into the available evidence that the molecular tumor fingerprint can be used in the surveillance of head and neck squamous cell carcinoma. Challenges to overcome, prior to clinical implementation, are also discussed.     

射频识别技术在智能交通信息采集中的设计与应用

提出了一种基于射频识别技术获取交通信息的新方法,完成了射频识别读卡器的设计方案,整个系统以MSP430微处理器为核心,包括发射、接收模块,通过串口与交通控制机通信。