Platymonas subcordiformis吸附镍离子的研究

分别研究了不同生长期海洋绿藻Platymonas subcordiformis对不同浓度Ni2+的吸附能力,以及藻液pH、光照强度和共存金属阳离子对藻细胞吸附能力的影响。对数生长前期藻细胞藻液和Ni2+的初始浓度为80 mg/L时的吸附能力较强,分别为7.76×10-5μg/个细胞和7.85×10-5μg/个细胞。当藻液pH介于9~10,光照强度为4 500 Lx时,藻细胞吸附Ni2+能力较强。此外,共存金属阳离子会抑制藻细胞对Ni2+的吸附。     

Solid state reaction synthesis and photoluminescence properties of Dy3+ doped NaGd(MoO4)2 phosphor

Dy³⁺ doped NaGd(MoO₄)₂ phosphors were synthesized by a traditional solid-state reaction route using NH₄HF₂ as a flux. The influence of calcination temperature on the crystal structure and spectral properties was studied, and the optimum calcination temperature for producing Dy³⁺ doped NaGd(MoO₄)₂ phosphor was experimentally confirmed. The concentration quenching of Dy³⁺ fluorescence and excitation-wavelength dependent spectroscopic properties were studied. On the base of both the Van Uitert's and I-H models, the electric dipole–dipole (D–D) interaction was ascribed to be the main physical mechanism responsible for energy transfer between Dy³⁺ ions. It was also discovered that the color coordinates of the Dy³⁺ doped NaGd(MoO₄)₂ phosphor depends on the Dy³⁺ doping concentration and the excitation wavelength.     

中国食品会展业的发展现状及其在食品品牌打造中的作用

本文就作为会展业的一个分支,中国食品博览会或中国食品博览会暨交易会(以下简称"食品会展业")发展现状、科学策划与实施、发展对策分析以及在食品品牌打造中的作用等进行了综述,提出了我国食品会展业发展的新思路、新对策等可行性建议。     

核-壳型脂质体基因载体的研究进展

脂质体作为一种重要的非病毒基因载体,在核酸和药物转运方面有着巨大的优势和潜力。近年来脂质体基因载体的研究基础上,主要介绍了脂质体-聚阳离子-DNA复合载体(LPD)和脂质体-磷酸钙纳米粒子复合载体(LCP)两种核-壳型脂质体基因载体,展望了核-壳型脂质体基因载体的发展方向及其在基因治疗领域的应用前景。     

超分子络合物β-环糊精-苯甲醚/苯甲酸乙酯/间甲酚的核磁共振氢谱分析

以β-环糊精与苯甲酸乙酯、苯甲醚和间甲酚在水相中通过范德华力发生包合反应形成了主客体超分子络合物,并用核磁共振氢谱对络合物进行了表征.同时通过分子模拟计算,证实了发生包合反应的可行性.通过核磁共振分析,给出了客体分子在β-环糊精空腔的可能构象.     

市售水基切削液成分分析及绿色优化策略

对国内市售水基切削液进行成分结构分析,结果初步鉴定市售水基切削液为黄色透明黏稠状液体,无刺激性气味,长期放置无分层、无相变、高低温均稳定;pH为8~9;固含量约为36%;通过红外光谱、核磁共振检测分析,市售水基切削液主要含有酯、烯烃、醚。经过原子吸收光谱法鉴定切削液中含有极微量的Na。并提出了合成绿色切削液的优化措施,在防锈剂、防腐剂、极压润滑剂和消泡剂等添加剂的选择上进行了讨论。     

氯化钙处理对鲜切芹菜生理与品质的影响

目的研究不同浓度的氯化钙处理对室温下贮藏的鲜切芹菜生理品质的影响。方法分别采用化学滴定法、紫外分光光度法、称重法分析测定了鲜切芹菜可滴定酸、可溶性蛋白、还原糖、总糖、Vc、失重率等多项生理生化指标。结果芹菜经切割后在室温贮藏期间,可滴定酸、可溶性蛋白、还原糖、总糖、Vc含量呈现前期上升后期下降的趋势,失重率随贮藏期的延长逐渐上升;较低浓度氯化钙处理的可滴定酸、还原糖、总糖、Vc含量明显地高于对照和其他处理组,可溶性蛋白含量、失重率却低于对照组。结论氯化钙处理有效地保持了鲜切芹菜良好的生理品质,是一种简单、安全、有效的果蔬保鲜方法。     

市售食用植物油中矿物质元素含量的比较研究

采用微波消解处理,原子吸收光谱法测定食用植物油中Mg、K、Na、Ca、Fe、Cu、Zn、Sr、Mn含量.各待测元素的检出限依次为0.00280、0.0338、0.0523、0.00945、0.00539、0.00148、0.00289、0.0845、0.00516 μg/mL,加标回收率在96.6％ ～ 103.9％之间.购于自由市场植物油待测元素的含量之和,散装豆油为967.75 μg/mL和969.06μg/mL,瓶装豆油为847.52μg/mL,明显高于超市购置的豆油、花生油和葵花籽油,其中溶剂浸出油的金属总量低于压榨油.购于自由市场植物油金属元素总合量相似度大,与超市植物油间的相似度小,其Na/K范围为1.63 ～ 1.68,而购于大超市浸出豆油的Na/K最小为0.82,压榨油为1.11～1.56.本文可为植物油的鉴定和选择提供参考.     

Bio-conjugation of CaF2:Eu/chitosan nanoparticles with BSA and photoluminescent properties

CaF₂:Eu nanoparticles capped with chitosan and bio-conjugation of CaF₂:Eu/chitosan nanoparticles with bovine serum albumin (BSA) were synthesized via microemulsion method. As a surfactant, chitosan was employed to cap the nanoparticles during the synthesis process and provided functional groups, such as amino group for further bio-conjunction with BSA. CaF₂:Eu and CaF₂:Eu/chitosan–BSA nanoparticles were characterized by means of X-ray powder diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), ultraviolet spectrophotometer (UV), infrared spectrophotometer (IR) and photoluminescence spectrophotometer (PL). The XRD results indicated that the CaF₂:Eu and CaF₂:Eu/chitosan-BSA nanoparticles have crystallized well and the average sizes were about 16 and 19 nm, respectively. Images of FE-SEM showed that the average grain sizes of the CaF₂:Eu and bio-conjunction of CaF₂:Eu/chitosan nanoparticles with BSA were about 19 and 20 nm. The patterns of UV spectra and IR spectra showed that BSA was linked to CaF₂:Eu/chitosan nanoparticles. In the emission spectrum of the CaF₂:Eu/chitosan–BSA nanoparticles, characteristic emission peaks of Eu³⁺ within the wavelength ranging from 500 to 700 nm were observed, corresponding to the transitions from the excited ⁵D₀ levels to ⁷F_J levels. This confirmed that the Eu³⁺dopant ion is located in a Ca²⁺ crystal site with Td symmetry.