Bioeffects of chromium(III) on the growth of Spirulina platensis and its biotransformation

BACKGROUND: In this study the bioeffects of chromium(III) (Cr(III)) on the growth of Spirulina platensis and its biotransformation were investigated. Spirulina platensis was batch cultured in Zarrouk medium containing different concentrations of CrCl₃ · 6H₂O. Total and organic Cr contents in S. platensis were determined by inductively coupled plasma mass spectrometry (ICP‐MS), and Cr speciation was assayed by high‐performance liquid chromatography/ICP‐MS. RESULTS: Results based on the dry weight, growth curve, chlorophyll yield and morphology change of S. platensis indicated that the growth of S. platensis was facilitated by Cr(III) below 4.51 mol L^?1 and inhibited by a higher concentration of Cr(III). It was found that Cr(III) could be accumulated efficiently in S. platensis, with a highest Cr yield of 173.17 g kg^?1 and a highest organic Cr proportion of 50.19 g kg^?1 (96.04% of the total concentration of Cr). No evidence of oxidation of Cr(III) to Cr(VI) in S. platensis cells was found. CONCLUSION: The results of this study suggest that S. platensis could potentially be used as a safe food carrier to accumulate Cr(III) through some metabolic process. Copyright © 2009 Society of Chemical Industry     

Development of an assay for rapid identification of meat from yak and cattle using polymerase chain reaction technique

Yak meat is of good quality with fine texture, high protein and low fat content, and rich in amino acids compared with that of cattle, and it lacks anabolic steroids or other drugs. In general terms, however, the meat yield of yak is relatively low compared with that of the cattle. In order to prevent possible adulteration of yak meat with cattle meat, based on the sequence of mitochondrial 12S rRNA gene, a multiplex PCR-based approach was proposed for rapid identification of the meat from yak and cattle using three primers designed in this work. Through the combinatorial usage of three primers with a single reaction set, two fragments of 290 and 159 bp were amplified from the cattle meat DNA, whereas only a fragment of 290 bp was obtained from the yak meat DNA. Using the assay described, satisfactory amplification was accomplished in the analysis of raw and heat-treated binary meat mixtures of yak/cattle with a detection limit of 0.1% for cattle meat. The technique is fast and straightforward. It might be a useful tool in the quality control of yak meat and meat products.     

Microstructure, Mechanical Properties and Oxidation Behavior of a Hot-Extruded TiAl Containing Ta

对热挤压后新型Ti Al合金Ti-46.5Al-3Ta-2Cr-0.2W的微观结构,力学性能及氧化行为进行了研究。结果表明,该合金挤压后微观组织主要由γ和α2相组成近片层组织,其片层晶粒尺寸为50~70μm。通过不同冷却速率获得了等轴,近片层及全片层的结构,尤其是在油淬后的组织中发现了大量的块状相。拉伸试验结果表明,挤压后的合金室温屈服强度和抗拉伸强度分别从807和846 MPa,降至800℃的620和760 MPa,而其伸长率从2.16%提高至3%左右,说明该合金在高温条件下依然具有较高的强度。断口观察表明,与其他合金相比,该合金的裂纹长度较小,而且Ta的添加有利于合金塑性的提高。最后对新型Ti Al基合金在800℃氧化行为进行了讨论,发现Ta的加入可以降低氧在Ti Al合金的溶解度,同时因其本身具有低的扩散率,在升高温度时能抑制Ti O2的生长。     

快速凝固制备La2Mg0．9Ni7．5Co1．5Al0.1贮氢合金的相结构及电化学性能

采用感应熔铸＋退火处理及快速凝固方法制备了La2Mg0．9Ni7．5Co1．5Al0.1贮氢合金。系统研究了快速凝固对合金的相结构、微观组织及电化学性能的影响。XRD分析表明，随着冷却速率的增加，La2Mg0．9Ni7．5Co1．5Al0.1合金的相组成发生了明显变化。退火合金由αLa2Ni7主相（Ce2Ni7型结构）和少量LaNi3相（PuNi3型结构）组成。随着冷却速率的增加，合金中出现LaNi5相（CaCu5型结构）和LaMgNi4（MgCu4Sn型结构）相，且新相的相丰度增加，aLa2Ni7相和LaNi3相的丰度减少。EPMA分析表明，快速凝固方法制备的La2Mg0．9Ni7．5Co1．5Al0.1贮氢合金为柱状晶组织且晶粒细小。合金电极的电化学测试表明，冷却速率对合金的活化性能影响不大。随冷却速率的增加，合金的最大放电容量减少、高倍率放电性能下降。在较低的冷却速率下（5m／s），合金电极的循环稳定性改善不明显，而随着凝固速度的进一步增加（20m／s），合金电极表现出较好的循环稳定性。     

自然山区大气景观模拟显示方法初探

提出了一个模拟大气、云雾等自然环境的照明模型，对视线距离较大，视野开阔的自然景物造型，如山体造型，更具有真实感效果，可获得模拟云、雾等天气特征的三维地形风景图。实验效果令人满意，并具有简单实用之特点。     

便携式地面测控系统

为适应无人机地面测控技术的发展要求,设计一种便携式无人机地面控制系统。分析便携式无人机控制系统的基本技术和原理,着重探究便携式地面测控系统的工作原理,通过采用操纵杆和键盘指令由测控计算机完成向无人机靶机发送遥控指令。试验和测试结果表明,所设计的无人机靶机地面测控系统具有一定的可行性。     

下游梯级河川式水库冲淤计算与预测

本文考虑到下游梯级水库形态的变化同时受到上游梯级水库和其自身水库调蓄运用的影响,提出下游梯级河川式水库冲淤计算的方法。后经紫兰坝水库河工模型验证,表明该法精度良好,计算结果与实验比较一致。     

有界随机噪声参数激励下碰撞系统的矩稳定性

研究了单自由度线性单边碰撞系统在有界随机噪声参数激励下系统的矩稳定性问题.用Zhuravlev变换将碰撞系统转化为连续的非碰撞系统,然后用随机平均法得到了关于慢变量的随机微分方程.利用伊藤法则给出了系统一、二阶矩满足的常微分方程,根据微分方程的稳定性理论得到了系统一阶矩稳定充分必要条件的解析表达式和二阶矩稳定充分必要条件的数值算法,并对理论结果用数值方法进行了仿真计算.理论分析和数值仿真表明,无论是相对于一阶矩还是二阶矩的稳定性,随着随机激励振幅变大,系统的稳定性区域变小从而使得系统变得不稳定.而当调谐参数趋于零系统达到参数主共振情形时,系统的稳定性区域变得最小.当随机噪声强度逐渐变小趋于零时,由二种矩稳定性给出的稳定性区域变得一致.在一定的参数区域内,随机噪声使得系统稳定化.     

WPT—S有机硅改性防水加脂复鞣剂应用工艺研究

使用WPT-S有机硅改性防水加脂复鞣剂进行防水处理,可以制得柔软、滑爽、丝光感强的防水猪反绒服装革和猪正水染服装革,其两小时动态吸水率低于25％,并且具有良好的卫生性能。但需要严格控制温度、时间和pH值等工艺条件,而且要注意前后工艺平衡。     

纯相磷酸铁锂PLD靶材合成和表征

本研究着眼于确定制备纯相Li Fe PO4脉冲激光沉积靶材的合成条件。通过TG-DTA实验分析合成过程,XRD检测确定晶相,SEM观察表面形貌。结果表明,采用液相法在800℃、通有氩气(93%)和氢气(7%)的混合气体中焙烧制得纯相的Li Fe PO4粉末,经压合焙烧获得了纯相、高结晶度、大晶粒的Li Fe PO4靶材。利用脉冲激光技术沉积Li Fe PO4薄膜,薄膜结构致密,晶粒粒径达纳米级别。